In the UK, building regulations specify that all new cooking areas, utility rooms, restrooms and toilets require you to set up an extractor fan. This is likewise real if you are transforming a space in your home to among the above spaces. As a standard guide, if you set up a fan into a kitchen area or utility room it need to be a 6 inch, or 150mm, fan, and for a restroom or toilet it should be 4 inch, or 100mm. This measurement describes the diameter of the spigot, or pipe, that protrudes of the back of the fan.As soon as you have actually decided exactly what size fan you need for the space in concern, you have lots of choices to make about the functions that the fan will carry out. Normally a restroom fan will be wired into the lighting circuit, so that it goes on and off with the light.