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Natural Ventilation for Infection Control in Healthcare

Ventilation moves outside air into a building or a room in the building. It also distributes the air throughout the facility or room. The general purpose of ventilation in any building is to provide healthy air for breathing by both removing the pollutants from the air within the building or the room and removing pollutants originating from it too.

There are three essential elements to any building ventilation –

Airflow direction, this is the overall airflow direction within the building. This will be from clean zones to dirty zones.
Ventilation right, this is the amount of outdoor air that will be provided to a room, and it will be the quality of the outdoor air too.
Airflow pattern and airflow distribution, the external air should be delivered to each part of the room or building in the most efficient way. All of the airborne pollutants are generated in each part of the building or room; should also be removed, in the most efficient way.

The three methods of ventilation are natural, mechanical and hybrid. Hybrid ventilation is called mixed mode.

What is Natural Ventilation

As mentioned above, there are three methods of ventilation. Natural ventilation is when a purpose-built opening is placed in various places through a building. These are doors, solar chimneys, wind towers, trickle ventilators, and windows.

Natural forces, known as wind (thermal buoyancy forces), indoors and outdoor air density differences will push out the door through or other purpose-built envelope openings within the building.

Read also: Natural Ventilation Types and Benefits

This is what we know as natural ventilation. The natural ventilation of any building will depend on the building’s design, human behaviour, and the climate.

What is Mechanical Ventilation

Mechanical ventilation is where a mechanical fan will drive into or out of a building. You will find these are fans, and they can be installed in windows or walls, or into air ducts for supplying into or exhausting air from a room.

The type of mechanical ventilation that you need to use will depend on the climate. In humid and warmer climates, infiltration might need to be used in order to prevent or minimise Interstitial condensation. Interstitial condensation is when warm, moist air from inside a building penetrates a wall, floor, or a roof and meets a cold surface.

In these cases, a positive pressure mechanical ventilation system is the best option.

However, in cold climates, exfiltration needs to be prevented. This will help reduce interstitial condensation.

For a room like a bathroom, toilet or kitchen, but have locally generated pollutants, and a negative pressure system is the best option.

In a positive pressure system, the room is in positive pressure, and the room air is leaked out through envelope leakages or another opening. In a negative pressure system, the roof is in negative pressure, and the room air is compensated by sucking air from outside.

A balanced mechanical ventilation system is a system where air supplies and exhaust have both been tested and adjusted in order to meet any design specifications.

This will mean the room pressure will be maintained at either slightly positive or slightly negative pressures. This is achieved by using slightly on the equal supply of exhaust ventilation rates.

Comparing Mechanical and Natural Ventilation

natural ventilation working guide

There are advantages to both systems. For example, when a mechanical ventilation system is well designed, maintained and installed by professionals, you can expect a high-quality ventilation system.

  • Filtration systems may be installed in mechanical ventilation, so that harmful microorganisms, gases, particulars, odours and vapours can be removed.
  • Mechanical ventilation can work everywhere where electricity is available.
  • An airflow path and mechanical ventilation systems can be controlled entirely. For example, this can allow air to flow from areas where there is a source, for example, a patient with an airborne infection, towards areas where there are no susceptible individuals.
  • In general mechanical ventilation systems are considered to be among the most reliable in delivering the designed air flow rate. This is regardless of the impact of all variables and the ambient temperatures. Mechanical ventilation can be quickly and easily Integrated into air-conditioning systems. Not only this but the indoor air temperature and humidity are also easy to control.

There are a number of issues with mechanical ventilation systems, and it is essential to understand these before making any decisions.

  • Installation and maintenance costs for mechanical ventilation systems can be relatively high. If a mechanical system cannot be installed appropriately or maintenance, due to a shortage of funds, the performance will be compromised, and this can cause catastrophic consequences.
  • Mechanical ventilation systems occasionally have interruptions for a wide range of reasons. These can include utility service interruptions, poor design, incorrect management, reduced/poor maintenance, and equipment failure. If the mechanical ventilation system fails at a critical point, this can be expensive to fix.

Natural ventilation systems have several advantages, compared with mechanical ventilation systems.

  • Natural ventilation can be more energy-efficient, more so if heating is not required
  • Well designed natural ventilation system that could be used to access higher levels of daylight
  • A natural ventilation system can generally provide a higher ventilation rate more economically, simply due to the use of natural forces and large openings, like windows.

There are a number of drawbacks for natural ventilation systems to

  • Other maintenance costs of natural ventilation systems are quite low, if a natural ventilation system cannot be installed correctly, or poorly maintained, the performance cannot be compromised and can increase the risk of airborne pathogens being transmitted.
  • Natural ventilation only works for natural forces are available; for example, if there is no wind, there are no natural forces.
  • It is difficult to control the airflow direction of natural ventilation systems, as well as sustained negative pressure or positive pressure. This means there is a risk of contamination for corridors and other rooms.
  • Natural ventilation is a variable and very heavily dependent on external climatic conditions. The two driving forces generate the airflow, wind and temperature difference, can vary widely. Natural ventilation, therefore, it is difficult to control, with airflow high in some locations and stagnant in others. This causes the possibility of having a low air change rate during certain on favourable climate conditions.

Mechanical Ventilation vs Natural Ventilation for Infection Control

The decision to use and natural ventilation or mechanical ventilation for infection control should be based on the needs of the patients. As well as of the availability of resources, and the cost of the system.

The NHS policy tends to limit the adoption of mechanical ventilation, to the principle of medical treatment areas such as airborne infection isolation rooms. As well as operating theatres and associated rooms.

ventilation healthcare

This means that patient wards are usually not required to be mechanically ventilated, and then a natural ventilation system should be in place. Opening windows is usually the most common solution used within the NHS.

One of the most significant energy users in hospitals is air treatment. The low energy hospital study identified this as an area for saving by naturally ventilating or non-clinical areas, and current NHS guidelines have been adopted at this conclusion.

Mechanical ventilation is costly to install and maintain in isolation rooms. It also does not deliver the recommended ventilation right, and they failed to maintain negative pressure. Furthermore, in fact, might be on the positive pressure.

For example, Pavelcek et al. 2000, evaluated 140 designated airborne infection isolation rooms in 38 facilities. This was from 1992 to 1998, and they found that unwonted directional airflow out of the patient room was observed in 38% of the facilities. Some of the primary factors that were associated with the incorrect operation of the airborne infection isolation rooms included –

  • Shared anterooms 14%
  • Turbulent airflow patterns 11%
  • Automated control systems and accuracy is 10%
  • The ventilation system is not balanced 54% of failed rooms

Not only this but a number of problems related to the use of mechanical ventilation can arise if there is a lack of active collaboration between technical and medical staff. This could also occur with natural ventilation. However, mechanical ventilation does need more attention.

It was found that medical staff often have poor knowledge of how the intended operational performance of a ventilation system should work. Even with regard to the protective functions, the systems that were originally adequately designed can be misused, and the intended function will be reduced, and this leads to an increased risk.

Expensive and sophisticated ventilation systems are often not adequately integrated into the building design, or used and maintained correctly.

A building repair without adequate control may adversely affect nearby areas via mechanical ventilation.

Many of these issues can also occur with natural ventilation, however.

A comparative analysis of natural ventilation systems and mechanical ventilation systems looked at eight hospitals in Lima, Peru. Out of this hospital is five had an old fashion design, and three had a modern design. Seventy of the naturally ventilated infection patient rooms were included in the study.

These rooms were compared with 12 that we are mechanically ventilated. Negative pressure respiratory isolation room built after 2000, and this is what the analysis found.

  • Facilities built more than 50 years ago, which have large windows and high ceilings, with windows and doors open, had higher ventilation right then modern naturally ventilator dreams.
  • Opening windows and doors provided medium ventilation of 28 ACH, which is more than double the recommended 12 ACH in mechanically ventilated, negative pressure rooms. However, this relies on the right door and window operation. None of the rooms was normally operated with windows and doors open.

These results should, however, be used with caution, as the ventilation rates in the analysis were reported without detailed information and climatic conditions. For example, how fast was the wind blowing, and in what direction was it blowing?

Carbon dioxide measurement devices also impacted the right ventilation measurements.

Moreover, the fact that these measurements were taken in buildings that have multiple, interconnected spaces would have affected the outcome.

Testing Ventilation Performance

Ventilation performance in buildings can be evaluated with the following four aspects. These four aspects are linked to three basic elements of ventilation.

  • Is the overall airflow direction in a building from clean to dirty zones? For example, isolation rooms or areas of containment, such as a laboratory?
  • How efficient is the system in removing any airborne pollutants from each location in the room or building?
  • Does the system provide sufficient ventilation at the rate required?
  • How efficient is a system in delivering outdoor air to each location within the room, or building?

Two overall performance indices are often used. The ventilation effectiveness indicates how efficiently the airborne pollutants are being removed from the room, and the exchange efficiency indicates how efficiently the fresh air is being distributed in the room.

Engineers will define the local mean age of air as the average time the air takes to travel at the point at first entering the room, and the room means the age of air is the average age of the air at all points in the room.

The age of the air can be measured using tracer gas techniques.

Exchange efficiency is calculated from the air change per hour, and the room means the age of the air. In the case of a piston-type of ventilation, the exchange efficiency is 100%. For fully mixing ventilation, the air exchange efficiency is 50%. Exchange efficiency for the displacement of ventilation is in between the two; however, for short-circuiting the exchange efficiency is less than 50%.

The measurement or simulation can evaluate the effectiveness of ventilation. This means the ventilation of flow rate can be measured by measuring how quickly injected tracer gas is decayed within a room. It can also be by measuring the air velocity through ventilation openings, or adults within a room.

As well as the floor area. Airflow direction can be visualised using smoke. Computational fluid dynamics, and particle image velocimetry techniques will allow the distribution performance in a room to be modelled.

How to Keep a Room Well Ventilated with the Windows Closed

If you are completing a DIY project that exposes you to fumes, you can ventilate the room without opening any windows at all. The same applies if you are trying to replace stale air with fresh air simply.

Most of us consider windows the best way and the easiest way to ventilate rooms, as they do provide a healthy flow of air throughout the room and your home. However, it is possible to keep a room well ventilated with the windows closed.

Focus on the doors

Rather than opening any windows, where possible you can open the doors in the room. If those doors lead to other spare spaces that can significantly improve the airflow. Well, focusing on doors, it is important that you close any doors that lead to nowhere, such as pantries or closets.

This can keep air moving out of the other door rather than being trapped in any enclosed spaces. If you happen to have any doors that open to the outside of that have screens keep these open, even for just 10 minutes as it can drastically improve the ventilation within the room.

Turn on ceiling and table fans

If you have any standing funds or ceiling fans within the room, keep these turned on to a medium-high setting. This will promote the air movement in circulation around the room. Ceiling fans rotate the air between the topsides and bottom of the room and are able to cause a breeze that can be strong enough to push stale air and fumes out of a doorway.

Tabletop and standing fans are not quite as strong as ceiling fans; however, they can produce a similar result. Placement of these fans will make a difference to the air circulation within the room.

Have box fans in the entrances

Construction workers and professional painters will often have a box fan in the entrance. These powerful, relatively cheap devices, when used in the doorway, can pull air from outside of the room and push it in.

This displacement will remove style and fumes. This can make a significant difference when you are working on a project that involves fumes, paint, stains, and where the windows are unable to be opened.

Turn on the air

If you have an Aircon unit, then make sure you have it on. An air-conditioning unit can help to keep your room well ventilated as well. Air-conditioners remove the heat from the air and continuously circulate air in the home, this constant exchange of air gets rid of stale air, fumes and pollutants.

It is vital that you regularly replace the filter on your air-conditioner, as this can help reduce allergens and odours.

Window Ventilation Company – Covid Prevention

2020 has taken us all by surprise. At the start of the year, very few could have predicted that the world would find itself in the grip of a global pandemic. Governments around the world have had to take a huge array of steps and measures to reduce the spread of coronavirus and Covid-19. Over the past four months, most countries have been in a lockdown state, with everyone but essential workers being encouraged to stay home. But more recently, restrictions are being lifted and increasing numbers of people are being able to do more of the things we usually do. This could include going to work and spending time in more social settings. Of course, the virus is still present. So, if you run a business that hosts staff or members of the public in a commercial premises, you’re still going to have to make some changes to the way you operate in order to prevent it from spreading further.

This will be a multi-step process, focusing on various different aspects of your business and operations. Most companies now have social distancing stickers placed on the floor, hand sanitiser readily available and face masks used where necessary. But one area that many businesses are forgetting is ventilation. Here’s a little information on how ventilation could impact levels of coronavirus and how to prevent covid-19 inside your business with clever ventilation solutions.

REHVA’s Research

Earlier this year, REHVA (the Federation of European Heating, Ventilation and Air Conditioning Associations) decided to conduct some research in order to provide interim guidance on how businesses should operate and use building services in order to combat the spread of coronavirus during the pandemic. This research focused on commercial buildings and public buildings, including:

  • Offices
  • Schools
  • Shopping areas
  • Sports premises
  • Other spaces where only occupation by infected people is expected

While information on coronavirus and Covid-19 is limited, the REHVA has done its utmost to find effective best-practice recommendations based on evidence from the SARS-CoV-1 outbreak in 2003 and 2004. The following information is based on their research and recommendations.

How Does Covid-19 Spread?


In order to prevent the spread of Covid-19, you first need to understand how it spreads. There are two dominant transmission routes of covid-19. The first is via large droplets (such as the droplets that we emit when sneezing, coughing or talking). The second is via surface transmission (touching hands, faces and so on). Let’s focus on air transmission through large and small droplets for now.

Large Droplets

Airborne transmission through large droplets tends to occur when these droplets are released (often through the acts of coughing and sneezing) and land on surfaces within a two metre range of the infected person. People standing within a two metre radius of this individual can then catch the virus themselves. Preventing the spread of the virus through large droplets is relatively simple. You just ensure that everyone stays at least two meters apart from one another. You can also encourage the use of face masks to block the projection of large droplets.

Small Droplets

Small droplets tend to be much more difficult to control. They can stay airborne for hours and can be transported long distances, circulating around enclosed spaces. The coronavirus particle, in particular, remains active in common indoor air conditions for up to three hours. As you can imagine, these particles and droplets can be spread around spaces through airflows and ventilation systems. A two metre distance isn’t sufficient to stop the spread of coronavirus through small droplets and particles. Instad, you’re going to have to take a look at your space’s filtration and ventilation systems.


Bearing the above information in mind, here are some of the recommended solutions provided by REHVA.

Increasing Air Supply and Exhaust Ventilation

Exhaust Ventilation

The most important piece of advice is to supply as much outside air as possible to your indoor space. This should now be deemed an essential for covid-19 office prevention, as well as covid-19 prevention in any other commercial or public premises. You should consider keeping your ventilation on 24/7. Simply use lower ventilation rates when there is nobody present in the building. Exhaust ventilation systems in toilets should also be left on 24/7. Just make sure to use relatively negative pressures to ensure that faecal-oral transmission is avoided in these spaces.

Use More Window-Driven Natural Ventilation

natural ventilation

If your building does not have a mechanical ventilation system, you should make sure to open any windows that you can. This can cause thermal discomfort, with your commercial or public space becoming too warm or too cold depending on the weather. But it is important for the prevention of Covid-19 in offices and other spaces. This is also an additional step you can take even if you do have a mechanical ventilation system. All in all, an open window will significantly increase natural ventilation in any given space.

The only room where windows should remain shut is the toilets or bathroom. This is because open windows in these spaces that have passive stack or mechanical exhaust systems could contaminate airflow from toilets into other spaces. If you do not have exhaust ventilation in your toilets and you do have to open windows in this space, it is recommended that you also keep windows in other rooms of your building open. This will help you to achieve cross flow throughout the building.

Humidification Is Not Effective

You may be familiar with the advice that humidification up to 30% is effective in preventing symptoms and cases of the common cold in the winter. This is because nasal systems and mucous membranes are more susceptible to infections at a low RH of 20%. But this isn’t really effective when it comes to Covid-19. This is because Covid-19 is highly resistant to environmental changes and is only impacted by humidity at levels of 80% and above, accompanied by a temperature above 30 degrees. This, of course, isn’t feasible in an office, commercial or public space, as all occupants would be too uncomfortable to complete any work.

Safe Use of Heat Recovery Devices

Heat Recovery Devices

It is recommended that you turn off rotary heat exchangers during the coronavirus pandemic. This is because heat-recovery devices can carry the virus attached to particles from the exhaust airside to the supply airside if there are leaks in your system. In rotary heat exchangers, particles deposit on the return airside of your heat exchanger surface and can be resuspended when the heat exchanger turns to the supply airside. Put simply, this all means that virus particles in extract air can re-enter your building while your heat recovery devices are in use.

REHVA advises that if leaks are suspected in your heat-recovery sections, pressure adjustment or bypassing can be another option. This will help to avoid a situation where higher pressure on the extract side can cause air leakages on the supply side.

It’s good to note that transmission through heat recovery devices isn’t an issue if your HVAC system has a twin coil, or “run around coil”. It is also not an issue if you have any other heat recovery device that guarantees air separation between the return and supply side.

No Use of Recirculation

It’s important to be aware that virus particles in return ducts are able to re-enter your building if your centralised air handling units have recirculation. So, it’s important that you do not use central recirculation during the pandemic when it comes to well managed covid-19 ventilation. You should ensure that you close recirculation dampers, even if there are return air filters present. REHVA notes that these return air filters do not usually filter out viruses like coronavirus.

If you have a decentralised system, such as a fan coil unit, these will use local circulation and should be turned off. This will prevent resuspension of particles at room level. If your unit cannot be turned off, you should at least make sure to clean your systems regularly.

Duct Cleaning is Not Effective

It is not likely that virus particles will deposit easily in ventilation ducts. Instead, they will generally be carried away by the airflow within the system. This means that you do not need to clean your ducts any more regularly than usual. Instad, focus should be laid on increasing fresh air supply and avoiding recirculation.

It Is Not Necessary to Change Outdoor Air Filters

Fine outdoor air filters will provide reasonable protection against rare cases of low concentration, virus-contaminated outdoor air. It is important to be aware that clogged filters are not a source of contamination, so you do not need to change them any more frequently than usual for covid-19 prevention offices.

Hopefully, some of the above information will help you to implement good quality covid-19 prevention in your commercial or public space through the use of effective ventilation! All of the guidelines are easy to follow and each of the steps are relatively simple to implement. So, get started now for the best results!

Natural Ventilation | Types, Working and Benefits

Keeping your house cool and comfortable without impacting on the air quality can be challenging, especially in summer. While artificial methods of ventilation such as AC systems and fans have become increasingly popular over the last years, these have some downsides that are worth considering before picking a ventilation system for your hose.

Natural ventilation, instead, can reduce your energy consumption and leverage the force of nature to keep your living environment comfortable and ventilated. Strategically-placed openings in a building can encourage natural movements of wind without the need for mechanical means.

At its very core, natural ventilation works by making the most out of the difference in pressure created between the outside and the inside of your house by air temperature and wind. In turn, this airflow can decrease and increase the internal temperature and provide a suitable and enjoyable environment.

How Does Natural Ventilation Work?

As we have seen, natural ventilation leverages the difference in pressure created on opposite sides of the walls of your building. Such a big difference in pressure comes from different air temperatures and wind.

natural ventilation working guide

While this is the concept at the core of this passive ventilation system, a strategic natural ventilation system is a little more refined than this. The windows placed on the facade and roof of the building will open and close automatically, according to the settings desired.

The movements of the windows will happen by incremental amounts, for the system to reach the values of the settings regarding:

  • Room temperature
  • Humidity
  • CO2 levels

Natural ventilation systems or passive venting can achieve such precise levels thanks to meters that can read the exact external temperature, wind speed, rain potentials, and atmospheric conditions. These will be matched with internal room temperature, humidity levels, and CO2 levels. This cutting-edge technology allows a refined passive vent system to control the building’s internal climate.

Why Choose a Natural Ventilation System

Now that you have an answer to the “what is passive ventilation” question, let’s have a look into the benefits this type of ventilation in buildings can bring.

  • Cost Reduction

AC systems and fans can be effective in cooling down a room, but they can also significantly weigh on your monthly electricity bills. Such systems are not particularly energy-efficient, and they work through the use of artificial airflows. The level of maintenance required by such systems can only add to the average cost of such equipment.

For Natural Ventilation Systems – Contact us: 01702 826 267 or 0845 519 0560

  • Air Quality Improvements

Artificial air conditioning systems might reuse and recycle the airflow, which means that it is not always as fresh as you might think. Many individuals are also particularly susceptible to conditioned air, which can cause allergy-like symptoms and discomfort.

Instead, natural ventilation systems can improve the quality of indoor air by constantly providing a fresh stream of air coming through your building.

  • Reduced Carbon Emissions

Aside from consuming energy, some types of air conditioning systems can be detrimental to the environment and create carbon emissions. Natural ventilation systems, instead, work thanks to the natural air and pressure movements. Therefore, there won’t be any type of emission involved – making them the optimal choice for anybody who wishes to live a low-waste, sustainable lifestyle.

  • Consistency

One of the biggest downsides of air conditioning systems and fans is the fact that they will only keep your home or building cool when they are on.

However, if you decide to save on energy and switch them off, your living space is likely to heat up rapidly. Instead, due to the incremental movement of natural ventilation systems, you can enjoy a constant temperature level, set at a pleasant level.

  • Internal Temperatures Control

This type of natural internal control is ideal for enjoying a pleasant level of temperature without much effort. The customized settings allow you to pick the temperature level and airflow you prefer and keep it at a constant standard.

  • Creates Indoor Air Movement

Certain AC systems recycle the air, creating a direct flow toward the user. Instead, this natural ventilation system creates an air movement that is entirely natural and homogenous. This is ideal to avoid temperature drops or spikes during the day while adapting the climate to your requirements.

  • Humidity Control

Increased humidity levels or dry environment can have serious consequences on the structural wellbeing of a building. It is common to see humidity stains on the ceilings of today’s houses. These can be due to poor air circulation or condensation. Instead, passive vents allow for a constant airflow that reduces this unbalance.

Wind-Driven and Buoyancy-Driven Stack Ventilation

natural ventilation types

Two types of systems characterize natural ventilation, Wind-Driven and Buoyancy-Driven stacked ventilation.


Also called wind-induced cross ventilation, this system leverages the pressure difference between the two sides of the building’s wall. The two different flows will cause the air to be drawn in from the high-pressure side of the wall, and be released out on the low-pressure side.


Also called the stack-effect, a buoyancy-driven stack ventilation system works by allowing the cooler air to enter the building at a low level. The low levels of a building are where occupants and equipment usually is. In turn, the movement of people and the use of machines and devices will heat the air up, which will become more buoyant. As it does so, it will rise through the building and escape through openings at the higher levels of it.

Suitable Building Types for Natural Ventilation

While they are ideal for anybody who wishes to live a sustainable lifestyle, the efficiency of these passive ventilation strategies varies depending on a series of variables.

Therefore, while it is sometimes the perfect building ventilation system, in some other cases, it might not be as efficient.
Ideally, cross or natural ventilation is perfect for those buildings that are:

  • 12m to 15m in depth
  • Five times deeper than the floor to ceiling height
  • 2.5 times deeper than the floor to ceiling height is ventilation can happen only on one side
  • If droughts are created, buildings might need to have courtyards and atriums to moderate them

Other environmental factors that influence the effectiveness of this system are:

  • How large the openings (windows) are
  • The stack’s height
  • The difference in temperature between the building’s top and bottom
  • The difference in pressure between the outside and inside of the building

During hot but still days, the effectiveness of natural ventilation systems can significantly decrease. This is a significant disadvantage of the system as these are the days in which you will need your house to be cool the most.

Also check: Home Ventilation Guide


Guide to Home Ventilation

Ventilation systems are such an important factor of our homes that more and more of us are becoming aware of. A good ventilation system means cleaner, fresher air which is vital for your health and the look and feel of your home. So what is available? There are lots of options with different prices. A standard heat recovery system with all the necessary work and labour can cost around £1000 or above, but this is for a house that is no more than 150 m2.

What is ventilation and why do we need it?

Ventilation involves the removal of stale air in the interior of a home as well as moist air, and replaces all the air with the replacement of clean, fresh air from the outside, which means that it can provide you with clean air. Adequate ventilation is essential and can assist with:

It prevents the build-up of excess levels of humidity, which helps with any type of respiratory conditions that you may have.
Provides air for fuel-burning appliances, such as woodburners.

Removes bad smells, such as food, smoke and sometimes even allergens.

House ventilation

When we live inside our homes, we are exposed to many types of air that can be difficult. Ventilation refers to the exchange of indoor and outdoor air. Even the most potent toxins in the house, such as carbon monoxide, and moisture can damage a house and good ventilation helps keep a home energy-efficient, safe, and healthy. Here are two types of ventilation systems that you need to look at. Uncontrolled ventilation is one type of system that you will need to look at. This is where you have natural ventilation in your home which you can’t turn on and off. For example air flows around poor-fitting windows, pipes and doors.

However, the best way to tackle this is by looking at controlled ventilation instead and eliminating the issues that come along with uncontrolled ventilation, such as sealing up the holes and cracks around doors and windows. Good design is vital when looking into ventilation systems, as well as looking at maintaining comfortable temperatures which includes your heating systems. If you have a heating system without adequate ventilation, you may end up with a home that’s warm but not as healthy or comfortable to live in as it could be and the air can become dry and even stale.

Controlled ventilation

The most common form however, is known as controlled ventilation. There are many different kinds so let’s run through some to give you a deeper insight into how they all work.

Exhaust ventilation systems

Exhaust ventilation systems

These work by depressurizing your home. The system exhausts air from the house through passive vents and is best for those living in colder climates. In climates with warm humid summers, depressurization can draw moist air back into building wall cavities, where it causes moisture damage, so this is a good system to the northern hemisphere. They are relatively inexpensive and easy to install. Usually, an exhaust ventilation system uses a single fan and it is connected to a centrally located source point in the house. Or, in other designs, the fan is connected to ducts from several rooms, and adjustable, passive vents are installed into all rooms to promote fresh air. Passive vents may need larger pressure differences than those created by the ventilation fan to work to maximum potential.

Supply Ventilation Systems

Supply Ventilation Systems

Supply ventilation systems use a fan to pressurize your home. This forces air from outside into the building as air leaks back out through holes in a shell, bath, or fan ducts. Supply ventilation systems allow exceptional control of the air coming in and out of the house. It works to pressurize the house, and the ventilation systems minimize any outdoor pollutants and toxins in the living space. It will also prevent any issues with combustion gases with fires and other gas appliances. It can be used to dehumidify also. An in-line duct heater is another option for this type of system but it will increase the operating costs of the system.

There are three types of whole-house mechanical ventilation systems which you will commonly see as:

  • Exhaust-only
  • Supply-only
  • Balanced

Each of the above will use ducts, fans, dampers and controls and your home will need to be evaluated to look at the path in and out of the home.

Mechanical Ventilation with Heat Recovery

Whole-house MVHR systems extract warm, damp air from inside your home and draw in fresh air from the outside. The warm stale air is passed through a heat exchanger and then is fed outside. The cool, fresh outside air is also passed through the heat exchanger, separate to the passage outside and is pre-warmed before it’s pumped back in. It captures and recycles heat but doesn’t produce it.

Some of these systems will have an automatic or manual setting and an air filtration is commonly built into all MVHR systems to prevent pollen and other particles from entering the home which would be counterproductive. Systems typically run continually at 80% efficiency and you can’t hear the system running at all. The general cost of a MVHR system can cost in anything from £1,500 to £3,000 but this may differ depending on your house size, and intricacies of the installation.

An HRV can recover up to 5 times more energy than it costs to operate it which means it’s an incredibly efficient appliance and they work well even when conditions outside are at their worst and HRVs ventilate, 24 hours a day, every day. You need an exceptional installer for a Heat Recovery System which has been well designed and is fit for purpose for your house size and more. A heat recovery unit can be placed in your loft, in a cupboard or even a ceiling void. It is best to look at installing it in an area where the heat is most enveloped. If you live in a particularly built up area with traffic, then passive systems may not work as well and this system will ensure that you get the clean air that you desire.

Alternative Controlled Ventilation Systems

If it’s not possible to fit a new network of ducting into your home, then you want to look at a central ventilation system which come as:
Positive input ventilation (PIV) – It works by drawing in fresh, filtered air into a property from outside, works well in an apartment block for example.

Mechanical extract ventilation (MEV) – This is a centralised system which gives clean ventilation by reducing the excess moisture using a multi point extract.

The difference between MEV and MVHR is that MVHR offers a balanced system which provides you with extract and supply, and MEV merely extracts the heat, such as wet heat from kitchens and appliances.

There are some other systems that are known as passive ventilation systems. These systems typically combine one of a variety of exhaust methods (wind, thermal or mechanical), with a separate passive air system. Typical components are likely to include humidity-controlled air inlets and outlets as well as passive air inlets located on exterior walls or windows, which automatically regulate airflow. This won’t be at all affected by any variations in wind pressure outside. The incoming fresh air can be passed through a special heat exchanger. This will work to try and recover heat from the extracted air. Some of the advantages are:

  • Greater simplicity.
  • Lower first cost.
  • Reduced electric usage.

Passive Ventilation

Passive ventilation is a natural ventilation system that makes use of natural forces, which may include wind and thermal buoyancy. This will help circulate the air and keep it clean, working to regulate the internal air temperature whilst maintaining fresh air and keeping stale air away. This usually occurs by the opening and closing of windows and vents which act as an air supply. Here are some reasons why passive ventilation works well:

  • Reduced costs: You are only relying on nature and the natural outdoor forces, so you’ll save significantly on your energy consumption.
  • Low maintenance: Passive ventilation does not require costly maintenance.
  • Cleaner air: Passive ventilation systems ensure that clean air is flowing constantly which will improve your general health and improve any other conditions relating to poor air quality.

There may be factors that will hinder your passive cenatilion such as the direction of the wind and the temperature including the position of windows and doors, which can affect air flow. You can keep on top of your air flow rate with some simple equations, however.

The air flow rate through a ventilation inlet opening forced by wind can be calculated using the formula Q = Cv x A x v where:
Q = air flow rate (m3/s)
Cv = effectiveness of the openings (assumed to be 0.5–0.6 for perpendicular winds and 0.25–0.36 for diagonal winds)
A = free area of inlet openings (m2)
v = wind velocity (m/s)

Investing in good quality ventilation is going to vastly improve your air quality as well as the value of your home, so be sure to do your research and look at how you can change the quality of your air.

Window Styles: All Different Types of Windows

Windows are not only a large financial investment, but they play a significant part when it comes to the aesthetics of your home as well. Windows are both functional and can make your home appear more stylish and beautiful. It’s a big decision that will require you to consider factors such as your home’s style, your budget, and what you’re trying to achieve throughout your space.

Shopping for new windows can be a challenging task. It’ll help if you educate yourself about the different types of window styles before you invest any money into the project. There are a variety of UK window styles to choose from that may peak your interest. Review the details and benefits of each option so you can determine the best fit for your home.

Casement Windows


Casement windows crank open horizontally on hinges mounted on one side at the top and bottom. One side will pivot open like a door whilst the other side remains stationary. They are a very common and popular choice among homeowners. They are a bit more modern visually and can catch and direct a nice burst of fresh air into your home. A side hung casement window is the most common in the UK.


  • Good at keeping out drafts since the window seal is generally quite tight.
  • Excellent ventilation, which makes them useful in directing cooling outside air into the house.
  • They tend to be relatively secure against intruders since the open space is fairly narrow when the windows are open.

Tilt & Turn Windows


Tilt and turn windows are practical choices that fit modern window styles nicely. They’re extremely popular in homes throughout continental Europe. Since they’re typically tailored to each customer, you may find the costs tend to be a bit higher. It’s an excellent choice if your home is more modern in style. These versatile sashes have a hinge on one side and usually a hinge on the bottom side. Each sash is operated by a different angle of the handle, which is great if you want variety.


  • Very secure against roaming kids, pets, and protection from possible intruders.
  • They are good space savers.
  • Good at keeping out drafts since the window seal is generally quite tight.

Sash Windows


Sash windows operate through a sliding mechanism, either vertically or horizontally, which is different from casement windows that have a crank and hinge. They can be either double or single hung if you choose the vertical sliding type of sash window. These windows are popular in mid-century modern homes styles. Sash or slider windows are a good choice when you need to constantly open and close windows.


  • Sliders have no cranks or mechanisms, so they are very durable and space-saving. 
  • They have good ventilation and flexibility.
  • The windows tend to be cheaper than other styles due to the simplicity of their design.

Bow or Bay Windows


A bow or bay window is a combination of windows that together form a unit that extends outward from the wall surface of the house. A bay window will be more of a square shape, whilst the shape of a bow window will be more curved. They’re excellent for creating a unique visual effect in living rooms, family rooms, and parlors.


  • Bay or bow windows are gorgeous and create a design statement like no other home feature. 
  • These windows are ideal where you want a constant view of the outdoors. 
  • These windows provide you with extra interior space by offering shelf space for growing plants or displaying decorative items. 
  • Small bay windows draw in a lot of light and can serve as greenhouse windows for growing herbs and other plants.

Fixed Windows


You might think of a classic picture window when visualizing a fixed window. A fixed window refers to any window that uses a glass pane fixed within a window frame that does not open or close. They come in many different shapes and sizes. You can even buy pre-made stained glass that draws in colorful light and is very pleasing to look at. They’re perfect for providing view and light where ventilation and egress are not needed.


  • Fixed windows are permanently sealed, so they offer better energy savings than other windows types. 
  • The simple design lends itself to modern home styles. 
  • Allow for light in hard-to-reach spaces.
  • Infinite decorative possibilities.
  • Fixed windows tend to be cheaper than other window styles.

Georgian Windows


Georgian windows offer a historic and distinctive design for any home. They’re one of the most iconic window styles in Ireland and a classic choice that never gets old. They can be either sash or casement windows, with their distinctive characteristic of six (or more) glass panes divided by narrow profiled glazing bars. Traditionally, Georgian windows were made from wood, though nowadays, uPVC Georgian windows are attractive and can look fairly authentic.


  • Energy-efficient.
  • Secure.
  • Gorgeous and timeless.

French Windows


French windows are similar to standard casement windows, which are attached by a hinge to the window frame on one side only, but they don’t have a central post. Instead, they create one large opening, without any structural elements obstructing the view from the window. They are full-length hinged double sashes that generally open inwards instead of being equipped with a sliding mechanism.


  • Allow for a lot of light and fresh air.
  • Grants you an excellent panoramic view to your front yard or patio.
  • Help save energy and cut down on electricity bills.
  • Work well as an additional safe exit or entrance to your home in case of an emergency.

Skylight or Roof Windows


A skylight is defined as a fixed window installed in a roofline, while a roof window refers to a similar window that can be opened and closed to provide ventilation. They’re excellent for introducing light in dim spaces and where window space is limited. You might find them in attics or upstairs bathrooms.


  • It can add light to the attic and second-story spaces that are usually dark. 
  • Venting roof windows can help exhaust hot air in summer.
  • Constant, direct exposure to the sun means these windows can help heat spaces in winter.

Double-Hung Windows


Double-hung windows feature two large sashes (frame units surrounding glass panels) that slide up and down within vertical tracks. It is common for the sashes to be counterbalanced by springs hidden in the side tracks in modern double-hung windows. You’ll often find them in homes with classic traditional styling.


  • They’re made by many manufacturers, so your selection is very wide. 
  • Prices are generally reasonable, due to the wide availability of this window type.
  • Typically easy to open and close, thanks to springs or weights. 
  • Tracks are vertical, so they generally don’t fill up with dirt.

Glass Block Windows


Glass block windows are fixed windows made with architectural glass blocks, usually mortared in place. They can block views whilst still allowing light to pass through because of the semi-opaque glass construction. They’re best for areas such as bathrooms, showers, and basements where you may want some light to shine through but to obstruct visibility. Some styles include ventilating panels built into the unit.


  • They’re the most secure of all windows since the heavy, thick blocks are mortared in place permanently.
  • Work well in areas where privacy is important.
  • These windows have very good insulating properties.
  • They’re durable and rarely need replacement.

Choosing the Right Window for Your Home

You should now have a better idea of your window options, which style might look best in your home, and the benefits of each. There are many window styles out there and on the market. This reality can be good because you have options but also challenging because it may cause you some stress and confusion as you think about all the possibilities.

Although most homes will include more than one style of window, designers don’t recommend mixing too many different styles in a single home. It may create a disjointed and disorganized look that will be unappealing. You want your window of choice to fit the style and architecture of your home, so keep this in mind as you shop around.


The right windows will be pleasing to look at and use and can boost the attractiveness of your home. Spend some time reviewing these window styles so that you can begin to narrow down your list of options and what may be suitable in your home. It’s a juggling act between considering how much you want to spend, what look you’re going for, and what benefits are most important to you. Give yourself plenty of time to think about your choices and try to picture what each style will look like in your home before investing any money. Remember that it’s best to stick with a primary style and add in some variation if you choose but not to overdo it.

What Are The Different Parts Of A Window Called?

Understanding the different parts of a window can aid you in choosing the ideal set of windows for you, as well as helping you to care for your windows and ensure that they can stay in tip top condition for as long as possible. You may be under the false impression that a window consists of nothing more than a frame and some glass, but this couldn’t be further from the truth. Luckily it needn’t be difficult to get to grips with the different parts that contribute to creating a window, as it’s simple to understand the features that make up the perfect set!

Most of the common windows that you are able to source consist of two main components – the outer frame and the sash. The outer frame is essentially the surface area, or the external casing of your window, and inside of the frame is the aforementioned sash as well as the glass too. The inside area of the frame is known as the wash, and it’s the feature of your window that holds the glass in place. A great example could be a single-hung window, as sash is the piece that you use to slide the window open. 

Contact Us for Cost Effective Ventilation Solutions

When it comes to the windows frame, there are 3 main features that come together to create a strong and sturdy perimeter that can support the weight of the glass. First of all you have the sill, which is the horizontal strip that is placed along the bottom line of your window frame. Second comes the jamb, which offers vertical support for the window frame, followed by the final feature, the head, which lines the top of frame to complete the square or rectangle. 

The sash is made up of several different components, each of which are equal in their importance. The stiles make up the vertical sections of your windows sash, whilst the horizontal sections are commonly known as rails. 

The sash outlines the most important feature of your windows – the glass. The glass inside a window is often referred to as the windowpane, which references the different glass sections that come together to complete the piece.

A very common decorative concept that can take your windows to a whole new level are features called grilles. These grilles are essentially an option that allows you to add some lines that can divide your glass, both inside the windows glass itself (known as GBG’s or grilles between glass) or actually on top of the glass’ exterior surface (referred to as SDL’s or simulated divided lites). You can get many other decorative features to upgrade the individuality of your windows, so you needn’t stick with a simplistic approach if this isn’t for you. 

Windows can come in many shapes, sizes and styles, but they all consist of the same main features that have been detailed above. Now that you have been able to familiarise yourself with the different components that contribute to the creation of a window, you can explore our amazing ranges that will no doubt fit your every need. 

How Do Greenhouse Window Openers Work

Making sure that your greenhouse has enough ventilation really is crucial if you want to keep your plants healthy in the middle of the summer. If your greenhouse doesn’t have enough ventilation, then you may find that the lack of humidity and the extreme heat harms your produce and that it also stops them from growing. A fantastic way for you to make sure that your plants are growing as they should, would be for you to provide them with the perfect environment. This can be done by investing in electric greenhouse window opener.

What are Greenhouse Vents?

Automatic greenhouse vents have a piston which gives them the ability to either open or close automatically. When the warmer weather hits, your vents will open and when the temperature drops, the vents will stay closed. Greenhouse vents are very easy to install. The pistons have a specially designed wax which when heated, expands. The greenhouse window openers can be installed onto any greenhouse and you don’t need to operate them at all. The type of vent that you invest in will largely depend on where you would like your greenhouse vent to be. You can have it on the roof, or as a side vent if you want. The vent that you do decide to invest in will largely depend on the plants that you have and the amount of sun you get.

If you are concerned about your vent not being in the right place, then you may want to try and install it where the sun hits the most. That way it will open up whenever the hottest part of the greenhouse exceeds a certain temperature. This is ideal if you have plants that don’t require as much heat. If you are growing plants that do require a large amount of heat on the other hand then installing it on the coldest window in the greenhouse would work because in this instance, it only works when the coolest part exceeds the heat threshold you’d like. Ideally, having a vent at either side would work well if you have a large greenhouse because that way you can control both sides of the greenhouse at the same time depending on the amount of sun each side is getting.

Benefits of Greenhouse Vents

  • There are many benefits of greenhouse vents. If you were to fit one in your greenhouse then you will easily be able to save yourself a huge amount of time and effort. As the weather and the temperature in your greenhouse fluctuates, you won’t have to worry about opening the vents.
  • Automatic vents are the way to go if you feel as though you are constantly having to visit your greenhouse every single day just to open the window and they are also ideal if you work and don’t have the time to visit your greenhouse every single day.
  • A greenhouse that has a fantastic level of ventilation will easily keep your plants healthy and it will also make them more resistant to pest attacks as well. The main reason for this is because pests thrive on plants that are dried out or without adequate water. Vents will stop this from happening because they let cool air in, therefore stopping your plants from dehydrating as much.
  • If you’re concerned about pollinating insects then you’ll be glad to know that automatic vent openers let these types of bugs in, so that you can speed up the process of pollination without having to worry about manually controlling the temperature of your greenhouse.
  • Another benefit of an automatic vent opener is that it will ensure positive oxygen and carbon levels within your greenhouse to make sure that the environment is much more suited to plant growth.

All About Electric Greenhouse Vents

If you have an electric vent, then this will use some kind of power to open the vent. This can be in the form of a solar cell, battery or even line power. A lot of systems have a backup source so that the vents can be opened if the power should fail. Electric systems are much more advanced and reliable so if you want a long-term solution then they are certainly worth looking into. If you are on a budget on the other hand, then you may want to try and invest in an automatic one as this will do the same job but without the additional benefits. This is a great way for you to have a vent system without going over budget.

Greenhouse Window Openers

Top 10 Window Opening Types

Windows play an integral role in any home, and it is important that you do as much as possible to make the most of this. You need to look at what you can do to make sure you get the best possible windows for your home. Believe it or not, there are quite a few different types of windows to choose from, and each of them operates in a slightly different way.

This is why it is important to make sure you look at some of the different windows that are available and the different ways in which they open. Understanding the different windows you want for your home is really important to sort out before you get a quote. And this is something that you need to think about as much as possible. Here are some of the top 10 opening types of window you should definitely know about.

 1. Side Hung

Side hung windows are one of the most popular types, with hinges on one side, and a handle on the other. Simple and effective, these side opening windows offer maximum practicality, can be opened fully, and offer great security. The only drawback with side hung windows is that they can sometimes move with enough pressure, and this is something to consider with gale-force winds.

 2. Top & Bottom Hung

Top hung and bottom hung windows are of a similar ilk to side hung windows, except that they have a horizontal axis on either the top or the bottom. These windows are designed specifically for ventilation, without the windows being opened completely, generally for safety reasons. Ideal choices for top and bottom hung windows to be used would be classrooms and schools, where they offer great security as well as airing the rooms.

 3. Side Guided

Side guided windows share a lot of similarities with the side hung windows. However, the main difference here is to do with the hinges that are used. Side guided windows tend to have the window sash move across when opened, so this lends an aesthetic without visible hinges. This is a fine choice for those looking to improve and boost the aesthetic appeal of a home.

 4. Top Guided

Top guided is a very popular design for those sorts of top opening windows that are wide and short, and these windows open out and up, with a handle at the bottom. These windows are a simple yet effective design, and this is something to keep in mind when making your choice. They are stylish, but they are not necessarily the most practical choice for homeowners.

 5. Top Swing

Similar to the top guided windows, but with much more to offer, the top swing windows can pivot almost 180 degrees, allowing you to experience the full impact of the window. It lets you air the room much better while at the same time being much easier to clean. Top swing windows are not overly common, as not all window manufacturers can create them. So it would be worth enquiring about these in advance.

 6. Tilt Turn

Tilt turn windows rank among the best and most popular of the window types in the UK due to their versatility. These windows operate on two separate axis; tilting and turning, and this is something that makes them so appealing to consumers. This is basically a design that combines the best parts of side hung and bottom hung windows, and this is something you need to keep in mind right now.

 7. Fixed

Fixed windows are not exactly a type that opens, but, instead, do what the name suggests. They remain fixed in place, and this makes them a much cheaper and more cost-effective option for a lot of property owners. There are a lot of things to consider here; of course, not every window in the home should be fixed, as this isn’t practical. But for aesthetic purposes, you might choose to have a couple of windows that are fixed.

 8. Folding

Folding windows are an excellent design for those property owners for whom space is a premium. The great thing about these windows is that they fold like a book and this allows them to free up the entirety of the window’s opening.

 9. Sliding

Sliding windows do exactly what they say on the tin, and this is one of the reasons why people like them so much. Sure, they might feel a little old-fashioned, but they can serve a practical purpose, especially as interior windows.

 10. Guillotine

Guillotine windows move along separate rails in the opposite direction of their separation, and this gives homeowners two different types of window. They don’t require space to be opened, but they do only open 50%, and this can be a drawback for a lot of people.

Make sure you understand what it takes to enjoy the best possible windows in your home, and this means you should focus on what it takes to make the right choice. Understanding the best possible window type for your home is important, and this means looking at the different types of window openings that are available.

window opening types

Window Openers For Large Roof Vents


Window Openers For Large Roof Vents

Why do I need two openers on one roof vent?

To give an example, while working with one of our roof light customers we selected some Mingardi Micro XL window openers to automate eight large and heavy roof vents in a school in Ilford.

These roof vents each weigh approximately 100 kg and have an opening edge which is 2050mm wide

We chose the Mingardi Micro XL window openers because each one has a 400N force and large 420mm opening distance.

The openers were coupled with the synchronising control box, which ensures both openers work together and at the same speed.

The combined pushing force for both window openers together is 80 kg which exceeds the required 50 kg needed

How do I calculate the force needed to open my roof vent?

For roof windows or roof vents the calculation you would use is:

Force = 0.54 x Window Weight

In the example we are using this would mean the force required would be 54 kg

Please note this calculation is not the same as top hung or bottom hung windows on a vertical wall where you need to take into account the height of the window and the distance you are pushing it as well

Why do I need two window openers on my roof vent?

The other aspect is the width across the opening face of the window.

When a window is wide and heavy you should use two or more window openers, this adds stability and balance pushing force as well as better compression when the window or roof vent is closed.

It is important to have some communication between window openers when you use more than one on the same opening.

This protects the roof vent from damage or twisting while opening, and if one of the window openers stops so will the other one


If you have a large or heavy roof vent please get in touch with one of our team to discuss the best options



Smoke Shaft ‘Lock-Out’ Clarified In Approved Document B


Approved Document B: Fire Safety sets out the regulations for providing a safe means of warning escape in the event of a fire.

There have been some areas that can be interpreted in different ways which has affected the smoke ventilation industry specifically,

One area that has been clarified in the 2019 amendments is how the smoke vents are triggered when smoke is detected in the common corridor and lobby