What is the Best Way to Ventilate a Room with No Windows

What is the Best Way to Ventilate a Room with No Windows

By Ruth MacEachern

Product Manager

Modern homes are designed to be as energy efficient as possible and to maximise the use of internal space. This can result in the creation of rooms which do not have natural ventilation to the outside of the building. Many houses feature a WCs, storage areas, and utility spaces which do not have windows, and it is important to ensure that these rooms have adequate airflow.

Why do windowless rooms need ventilation

Our daily activities create substantial amounts of water vapour in the air of our homes. In a typical home, each resident will be responsible for more than 2.5 litres of water. As air temperatures cool during the evening or in colder rooms, the water vapour in the air will settle onto cold surfaces to form condensation.

Over time, condensation can soak through permeable surfaces such as paint and wood to create damp spots where mould will start to grow. The damp areas can cause damage to plaster work that is expensive to repair, and as mould develops it can damage soft furnishings, discolour paintwork, and release spores that may cause allergic reactions.

Windowless rooms such as storage areas and WCs where there is limited natural ventilation will often trap humid air, which can lead to damp and mould developing quickly.

If you live in an area of the country where the local geology gives rise to higher levels of radon, this too can build up in rooms with poor ventilation. Radon is an odourless, colourless radioactive gas that has an ionising effect on dust particles. High concentrations of radon in your home are dangerous to your health and are associated with several cancers.

By improving the ventilation of a room with no windows, you prevent that room from becoming a potential source of mould and stop the build up of radon gas to protect the health of your household.

Improving ventilation in rooms without windows

In rooms with an active source of moisture, such as a utility room, ensuite bathroom or WC, it is important to ensure that there is an appropriate extractor fan. According to current building regulations, there are stated requirements for the minimum extract rate for air:

• Sanitary Accommodation such as a WC should be equipped with an extractor fan with a minimum of six litres / second
• Utility Rooms require an extractor fan that can remove thirty litres of air per second
• Ensuite bathrooms should include an extractor with fifteen litres of air per second – this is the same flow rate as a regular bathroom as humidity levels can get quite high in an enclosed space

To ensure efficient operation, the extractor fan should be mounted high up on the wall or ceiling opposite the door and vent to the exterior of your property. This ensures that air is drawn through the room to remove water vapour as quickly as possible and stop condensation from forming.

Storage areas such as under stair cupboards are often in the centre of the building, and fitting an extractor fan is not always practical. Such rooms may not be regularly used so there is often little air movement.

To ensure that air flow in such spaces is sufficient to prevent a build up of moisture in the air, a whole house ventilation system is often the best option. Positive Input Ventilation Systems (PIV) such as EnviroVent ATMOS rely on a central unit mounted in the loft. This unit draws fresh filtered air into the building at roof level and then distributes it throughout your home to displace the stale air and reduce humidity.

PIV systems can be retrofitted into a home with minimal disruption and are highly efficient in operation. Because they reduce humidity levels in all areas, they prevent condensation, damp, and mould throughout the whole building.

Find out more

If you have enclosed spaces or windowless rooms in your home and are concerned about the health risks of damp and mould that they pose our local specialists can help. EnviroVent have ventilation experts across the UK who can visit your home to conduct a FREE survey that will identify causes of condensation and then provide advice about the best way to deal with them. Simply enter your postcode below to find an EnviroVent expert in your area.