Extractor fans are more important than you might think, and choosing among them can be a challenge.

They are important in homes -- particularly in washrooms -- because they remove humidity and help prevent damp. Mould growing in bathrooms is believed by many experts to cause a variety of illnesses, and it can be prevented by simply eliminating humidity as soon as it is produced.

These fans, also called vent fans or suction fans, serve other purposes and can be used in other rooms.

Homeowners often put very little effort into choosing these fans because they are largely unseen -- if installed and located correctly -- and because consumers do not understand the vital role they play in keeping homes safe and disease-free.

With a few facts at hand, it is easy to make the right choice of extractor fans for a new or existing home. Here are a few things to keep in mind.

First, consider the location. While the bathroom is the most common location for these types of fans in homes, they can be used in any room. Extractor fans can remove cooking heat from a kitchen, humidity and smells from a laundry room or cigarette smoke from a sitting room. They’re useful in workshops or garages where paints or chemicals produce toxic odours that can harm users and other household members.

Second, consider a fan with a housing that compliments a home’s décor or blends into it rather than one that makes its presence obvious because of a striking colour or pattern on the case. Some fan manufacturers make fans that draw attention to themselves, but customers almost always want fans that are barely noticed.

Third, noise matters. While your first inclination may be to choose the quietest fan you can get, surveys and tests have repeatedly shown that many users prefer noisier fans. Why? Bathrooms, where these fans are commonly used, can sometimes be the location of unattractive and unpleasant sounds that people do not want heard outside the room. Noisier fans increase a user’s sense of privacy even if the fan’s noise can only be heard inside the room.

Finally, consider size and number. While a small bath may be well served by only one fan, longer, larger rooms may need more than one fan. A larger fan, one with more powerful suction or better outside venting might be adequate in many cases, but two smaller, less powerful fans may do the job better if they are well placed.

While the choice of fans is ultimate up to the consumer, keeping these bits of information in mind may well help those considering buying an extractor fan.