Which Ventilation System is Most Environmentally Friendly

Good ventilation is essential in any home. Having fresh air and controlling humidity make your house a more pleasant place to be and help reduce the concentration of allergens in the air and stop condensation.  Modern ventilation systems are designed to be as energy efficient as possible. They feature multiple innovations that help reduce their impact on the environment and reduce your electricity bills.

Different types of ventilation

Mechanical ventilation systems can work in one of two ways. Either they actively push the air out of the building envelope and create a lower-pressure environment that draws air in from outside, or they actively draw air in from outside to create an higher-pressure climate that displaces the stale or humid air inside your house.

Extractor fans are the most common type of ventilation and work by installing a fan on the wall of your wet rooms (kitchens, utility rooms, WCs and bathrooms) to quickly remove humid air and prevent condensation from building up.  Whole house ventilation systems known as Mechanical Extract Ventilation (MEV) work similarly but use a central unit to remove air.

Alternatively, a positive input ventilation system (PIV) draws air into your home through a filter system into a central unit (typically installed in the loft of your dwelling). Then it disperses it through multiple rooms to displace the stale air.

A key point to note about whole-house ventilation is that it helps to spread warmth around your home, which can reduce your heating costs.

Measuring Environmental Impact

Extractor fans and other ventilation systems consume electricity when they are running.  In bathrooms, the fans are usually installed on the same circuit as your bathroom lights and so will run when the lights are on, although they can also be operated separately.  In kitchens, the fan may be separate  Modern extractor fans such as the EnviroVent Cyclone 8 include a humidity sensor which adjusts the power level of the fan to reduce moisture in the air as quickly as possible.

In typical usage, an extractor fan in a bathroom will use about 13-kilowatt hours of electricity over a year.  Depending on how the electricity was generated, this is the equivalent of around 2.5KG of CO₂ being emitted into the atmosphere.  Located in a kitchen, a fan will usually run for more extended periods and as such will use around 35Kwh over a year – resulting in CO₂ emissions of approximately 7KG.

Whole house ventilation systems run continuously to provide fresh air but consume much less energy than extractor fans in operation.  A PIV system without a heating system for incoming air will use approximately 29Kwh of electricity and have carbon emissions of 5.6Kg of CO₂, whereas a PIV system with a heater to warm incoming air will use 208Kwh and result in just 40.2Kg of carbon emissions over the course of a year.

Mechanical Ventilation with Heat Recovery (MVHR) systems incorporate a heat exchange to warm incoming air, and as such, will improve the overall efficiency of your home.  Such heat exchangers are highly effective, recovering up to 85% of the warmth from the outgoing air. A typical whole house system will less than 200KwH over a year equivalent to 38Kg of CO₂ emissions.

Find out more

Improving the ventilation in your home can help to reduce energy bills and your impact on the environment. Enter your postcode below to find a ventilation expert in your area who can advise on the most environmentally-friendly ventilation system for your home.