Your bathroom is on the inside of the building and so has no windows at all. This is more common in flats An overrun timer gives it time to complete the job. You can set how long it runs for when the fan is installed, but most models offer settings from 30 seconds to 30 minutes. If you’re going to use this feature, it makes sense to leave it running for as long as possible to make sure it removes as much humidity as possible. Range of 100mm domestic centrifugal extract fans for wall or ceiling installations, designed to work in accordance with two different operating modes: Extractors come in two sizes: 100mm/4 inches and 150mm/6 inches. In most cases, the 4-inch fan will remove moist air well enough to keep the bathroom smelling fresh and be less susceptible to mould. The only reasons you would need to consider a 6-inch extractor fan is if:

Bathroom Extractor Fans | Extractor Fans | Screwfix

Two speed options are available of 15 and 21 litres per second. 15 is the lowest extractors fans should be, so you have the option of increasing to 21 if you need more power or have a bigger bathroom.Each extractor fan in our list is best for a different purpose. The Xpelair C4HTS is by far the quietest coming in at an incredible 20 dB (although advertised at 16 dB). Slightly harder to install than the other three, make sure you read the instructions carefully. The Xpelair offers two speeds depending on how powerful you’d like it to be. This will vary on bathrooms size, and will have an effect on noise level. The slower the fan needs to work, the quieter it will be. The timer can range from 30 seconds – 30 minutes, again this setting will depend on how hard you need the fan to work. The EBB-N centrifugal bathroom extractor fans are suitable for many domestic and commercial ventilation applications where higher system resistance pressures are encountered.

Extractor Fans | Ventilation | Screwfix Extractor Fans | Ventilation | Screwfix

How much extraction you’ll need depends on how large your bathroom is, how well it’s already ventilated, and how many people will be using it. As extractor fans don’t use a massive amount of power, it’s best to go for the most powerful one available within your budget. This could be a good combo with the overrun timer; if there’s still a lot of moisture, even after the overrun, the humidity sensor will activate and complete the job. Do be aware, though, that the sensor won’t work as well if it’s dirty. Wipe it down every couple of months to ensure it works as intended. Recorded at 26 dB, it’s on par with the Envirovent and louder than the Awenta, although the Awenta offers extraction of less litres per second. So, if you have a bigger bathroom or condensation is a problem, it might be better you go for a slightly louder model that has more power.If you have access to roof space, an inline extractor fan system would be quieter and more efficient. The Eco Hand drier uses a powerful high speed layer of clean air to eliminate all drops of water from the hands leaving them totally dry in 10 seconds. If you’re concerned anyone in your home might forget to turn on the extractor, then definitely consider getting a model that includes a humidity sensor. The sensor will detect if the bathroom’s humidity exceeds a certain level and automatically switch on the fan. Building regulations require that a domestic bathroom fan must extract a minimum of 15 litres per second. However, almost all extractors on the market exceed this and average 21-25 litres per second. There are even some models that go as high as 68 litres per second. The Xpelair C4HTS is a terrific extractor fan choice, coming in at 20 dB. Advertised at 16 dB we believe it’s closer to 20 dB, which is still the quietest we’ve tested.