Exhaust Fan FAQ’s

How do I know how powerful my fan should be?

For the most common application (a bathroom) our base recommendation is 15 air changes per hour. For rooms that are prone to steaming up / condensation then you may wish to go for more like 20 or even up to 30 air changes. Depending on the application this number will vary, for example a small toilet cubicle will only require an extraction rate of 5-7 air changes. Other scenarios can have higher extraction rate requirements.

What do you mean by air changes per hour?

Air changes per hour is the number of times per hour the entire volume of the room will be extracted. For example 15 air changes per hour will mean the overall volume of the room will be extracted 15 times within 1 hour. Different applications require different amounts of air changes, for example a toilet cubicle will require less air changes per hour than a full bathroom as it does not have the demands that a shower and or bath provide with the generation of excess steam, moisture etc.

I want to replace my old exhaust fan – How do I do that?

Ceiling Exhaust Fan
If you are replacing an old exhaust fan in the ceiling the first thing to do is remove the old unit and measure the hole size (diameter) in mm. Measuring the cover is not suitable, we are not able to offer an alternative based on the size of a cover as they can be varying sizes that do not tell us how big the hole in the ceiling is. Once you have measured the hole size you can then go through our range of ceiling mounted fans to find a suitable replacement. If you cant find an exact replacement you can always go for something bigger and make the hole in the plasterboard larger to accommodate the fan.

Other factors to consider are the height of the ceiling cavity or the space that you have available to install the exhaust fan. Many ceiling mounted fans will require at least 220mm of space (some more and some less, this is a generalisation). To be sure measure the cavity space and cross reference this with the information we have on each product listing. If you have a large roofspace above the room then this is not a concern!

If the ceiling fan is ducted and the duct is already in place then you may wish to look at models that have the same diameter duct outlet. The majority of modern ceiling mounted fans are designed to be ductable and the suitable duct size will be available on the listing. If you plan on running new ducting from your fan then we sell a wide range of accessories including ducting and external vents. Just be mindful that ideally your duct run will be as short and direct as possible to increase the efficiency of the fan.

Window Exhaust Fan
The issue with a window exhaust fan is by removing your old fan you are left with a big hole in the window! With a window its necessary to find an exact size replacement, thankfully our website makes that easy for you! Simply go to the window exhaust fan category and select your hole size (diameter in mm) from the options on the sidebar. If we do not have your exact size then chances are we may not have an exact replacement, however you can always send us an email enquiry and we can double check.

Most window fans will sandwich between the glass. So you will have the motor on the inside with a vent on the outside. Connecting these two components creates a seal in the window.

Wall Exhaust Fan
You guessed it, remove the old unit and measure the hole size in the wall! Another factor to consider is the depth of the wall. It may be single brick, double brick or even thicker. Once you have measured the thickness of the wall you can begin looking at our range of wall exhaust fans. Most fans will have listed the wall thickness, in some instances it will not be a fixed value (it will have a tolerance). As long as your thickness is within that tolerance and the hole size matches you should be fine.

Depending on the model it may or may not come with an external wall vent / ducting. If you require a vent to go on the outside and some ducting we sell all of these parts in our accessories section.

I want something quiet!

This is a common request. The first thing to mention is noise is very difficult to quantify and is subjective! What one person considers noisy another will find tolerable etc. Whilst we strive to include all technical data and information on our website a decibel rating does not take factors such as the acoustics and size of your room into consideration. Generally speaking with exhaust fans the larger and more powerful the motor then the more of a component of noise associated with the fan.

A wonderful solution for the noise conscious is an inline system. This involves an inline fan situated in the roofspace. Firstly as the fan is located in the roof it can be positioned a little further away than directly above you. Secondly we sell a model called the TT Silent. This fan has been engineered to operate very quietly, for more information please click here. For more information on inline fans visit our inline kit section here.