Ventillation and Extractor Fans

What is ventilation for?

Ventilation is the exchange of fresh air from the outside and stale air and moisture from the inside of a property. Poor ventilation can result in harmful pollutants and moisture being trapped in the property which, in turn, can damage the health of people and the house itself.

Reducing condensation and mould growth

Through household activities such as showering, washing dishes and clothes, cooking and even just by breathing, we generate a lot of moisture that enters the air inside our homes. Without effective ventilation, this moisture can be trapped in the home and turn into condensation, particularly in the winter when surfaces such as walls are cold. The condensation can lead to damp and mould growth which can cause damage to your home and lead to respiratory illnesses for you and your family.

Protecting health

Without good ventilation, there will be more substances in the air that can cause harm to you and your family. This includes pollutants from cooking, cleaning products, hygiene products and fabric furnishings.

Why is ventilation important?

We spend most of our time (80-90%) inside buildings, so ensuring we’re in a healthy environment to live and work in is very important.

Ventilation improves indoor air quality by removing potentially harmful pollutants including cooking fumes, carbon monoxide, pollen and other allergens, and chemicals from paints, carpets, furniture and household items. It also removes particulate matter – tiny particles suspended in the air from sources like solid fuel fires, wood-burning stoves, mould and dust mites.

Ventilation also regulates internal moisture levels. Water vapour within buildings is mostly produced by human activities such as breathing, washing, cooking and drying clothes, and in some instances, moisture may also enter through the building fabric. When moisture in the air comes into contact with cold surfaces such as single-glazed window panes, it condenses and forms water droplets, known as condensation.

Condensation can lead to the appearance of black mould, which produces spores harmful to our lungs. Over time, damp and condensation can cause structural damage such as wood rot and cause damage to plaster.

Ventilation also helps prevent overheating, which is more likely to occur in cities, in top-floor flats or in well-insulated but poorly ventilated buildings. Overheating is an increasingly significant problem due to the effects of climate change.

Which rooms need ventilating?

Ventilation is particularly important for high-moisture areas such as the kitchen, bathroom or utility room. Using extractor fans and opening windows will help stop moisture from spreading to other areas of the house where it may condense on cold surfaces and lead to damp. Closing the doors to these rooms while they’re in use (and after) will also help.

Drier areas like bedrooms and living rooms still need ventilating. Leaving doors and trickle vents on window units open can help fresh air get around the room.

If you’re installing a mechanical ventilation system (see ventilation types below), background vents are required. This allows air to flow around the home as extractor fans in the wet rooms can pull fresh air through the dry rooms, and out through the wet rooms.

Bear in mind that all homes have some spaces without good airflow where damp can build up. Where necessary, pull furniture away from the walls by a few inches to allow passage of air, or drill ventilation holes into cupboards and wardrobes and avoid overfilling them with clothing.

Additional ventilation is required for certain types of room heaters. Gas and solid fuel heaters often require either a direct air feed or an air brick in the exterior wall to prevent the build-up of carbon monoxide. Ideally, a carbon monoxide monitor and alarm should be installed if you have one of these heaters.

Ensuring the walls, loft and sub-floor spaces are properly ventilated is another important consideration, particularly if insulation is being added which may block existing ventilation points, reduce breathability or trap moisture.

Following link provides more information from the Centre for Sustainable Energy