Review Window-Mounted Air Conditioner

There are many different types of extractor fans but they have one common purpose and that is to keep a bathroom or kitchen free from condensation and unpleasant odours.

They are relatively easy things to install and the type and size of fan that you need, will depend on the room that it is being used in and where it is being positioned.

Window-Mounted Air Conditioner

Fan Capacity or size

Fans come in different capacities and the size you need depends on the volume of the room.

- A kitchen fan must be capable of changing the air completely 10-15 times per hour

- A bathroom requires 8-10 changes per hour or 15-20 if the room contains a shower

- A cloak-room requires 6-10 changes per hour

Fan capacity = volume of room x required number of air changes per hour

Fan Position

Stale air needs to be replaced with fresh air so the fan should be positioned opposite the source of replacement air and as high as possible so that it extracts the hot air and draws in fresh cooler air.

Fan Types

Extractor fans come in four main types: window and wall mounted axial fans primarily intended for overall room extraction; ceiling fans which are often used above showers and extracting cooker hoods designed to be fitted directly above your cooker.

Window Mounted Axial Fans

Axial fans move air from the inlet side through to the outlet side of the fan. The blades work a bit like a wing of a plane. As they rotate the negative air pressure above the blade sucks in air and the positive pressure beneath the blade pushes it out.

This type of fan can only be fitted in a fixed window so is not suitable for a sash style window. They can be installed into a double glazed window but the glazing manufacturer will need to supply a pre-cut unit with sealed edges.

Window mounted fans are useful but they can look a little unsightly and there is always the issue of what to do with the supply cable.

Wall Mounted Axial Fans

These work in exactly the same way as a window mounted fan but instead of passing through glass, this type of fan is designed to be wall mounted with the expelled air being passed through a duct.

Ceiling Fans

As the name suggests, this fan type is designed to be fitted into a ceiling and is often used above showers. For this reason many shower fans also incorporate a halogen light and come with long lengths of flexible ducts that can be run through a loft or cavity.

Cooker Hoods

Some hoods filter the air, removing the odours and grease before re-circulating the air. Others suck out the stale smelly air, extracting it, before it is blown outside. Because the air is changed with extraction, this is the more efficient of the two methods.

An extracting cooker hood is installed by cutting a hole through the wall. 'Ducting' is fed through the hole, a grille is fixed to the outside of the house and the unit is wired in above the cooker. This type of fan expels moisture and filters out cooking odours and grease.

Re-circulating hoods are easy to install and just need to be wired in and attached to the wall above the cooker. They remove grease and odours but not moisture. To keep either type of cooker hood working properly, the filters need to be changed regularly or washed.

Fan Features to Look Out For

- Humidity controls - preset humidity levels trigger the fan to switch on automatically.

- Timer controls - enable the operating period to be set for a certain length of time.

- Ball bearing motors - help reduce motor noise.

- Back draught shutters - help prevent smells blowing back through the ducts.

- Multi speed motors - offer variable speed control, a useful feature to have in a well-used bathroom.

- Can be installed using flat 'ducting' - useful for concealed applications.

- Simultaneous fan and light operation - useful above showers.

- PIR motion sensor controls - useful in the dark and will ensure the extractor fan is always switched on when required.

Electrical Installations

Any electrical installation needs to comply with current regulations. If you are in any doubt always consult a qualified electrician.

Deciding on the Right Extractor Fan