How long should an extractor fan stay on for?
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Extractor fans are essential for diminishing heat hazards and the risks caused by indoor pollutants in the home. A modern household generally has at least two extractor fans - possibly more depending on the size of the property - but it can be difficult to know how long to leave them on for optimum effect.

How long should a bathroom extractor fan stay on?

Bathroom extractor fans reduce the humidity of your bathroom and are an excellent means of preventing mould growth

Ideally your bathroom extractor fan will be powerful enough to accommodate the size of your bathroom. For instance a bathroom of 70 square feet should be fitted with an extractor fan with a 70 cubic feet per minute (CFM) rating for optimum performance.

In this situation, the fan would execute a complete air change in the room in 15 minutes. If your fan has a CFM rating lower than the size of your room, a complete air change will take longer. A 40 CFM extractor fan in the same bathroom will take half an hour. You can also open your bathroom window to speed up the process.

When bathing or showering, the most efficient way of keeping your bathroom steam-free is to turn your extractor fan on before you turn on the water to get the air circulating before introducing any steam.

Keep the extractor fan running throughout your bath or shower and for a full cycle afterwards to make sure that the room is completely clear of moisture and humidity. You may also want to invest in constantly running axial fans or fans with built-in humidity setting.

If you love steamy showers and really can’t bear to do this, leave the extractor off while showering to let the steam accumulate. As soon as you finish your shower, open the windows wide to release as much steam as possible and then turn your extractor fan on. Set it to complete two full air changes.

How long should a kitchen extractor stay on for

By extracting harmful smoke and grease particles, a kitchen extractor fan increases the air purity in your home, especially during winter when most people keep their windows closed and less air escapes. But how long should you keep a kitchen extractor fan on for?

A kitchen extractor fan should execute a entire air change between 10 and 40 times per hour. There is always a trade-off between filtering speed and extraction capacity; extractors with a very fast air change speed do not filter grease as efficiently and are much more difficult to clean.

Regardless of power, the best thing to do is to turn the extractor fan in your kitchen on ten minutes before you begin cooking. This will ensure that there is a healthy air flow by the time you start to create any smoke or steam.

Keep your kitchen extractor fan on all the time while you are cooking. It is also helpful to leave it on for ten minutes to half an hour afterwards, depending on what sort of food you have been making and how much steam or smoke there is.

Frying strong-smelling foods such as fish can leave powerful odours - if you’ve been cooking with these, use your discretion and keep the extractor fan on for as long as you need. This continued air circulation will help to prevent lingering food smells.