These days you can buy an extractor fan for virtually any commercial or domestic application that you need a fan for. There are simple traditional through wall fans in a variety of sizes, commonly 6 inch or 9 inch ones. These types of fans can be of the simple on/off variety, or you can get ones with timers in them, or even temperature or humidity controlled ones bathroom exhaust fan
These types of extractor fans can commonly be found in use in kitchens and bathrooms, although certain regulations apply about where extractor fans can be fitted in relation to how near they are to water sources. You can now also buy them with PIR sensors in them. These are ideal for office toilets where the fan only comes on when someone enters the room, but goes off immediately they have left the room. Thus saving companies money on electricity.
There are now airflow quiet air fans with very high outputs that are virtually impossible to hear running, yet they use nominal amounts of electricity due to their innovative design.
You can also buy inline extractor fans for use in shower rooms or bathrooms, where modern regulations in some countries mean that a through wall fan cannot be fitted. This is to ensure electrical safety in a damp environment.
For larger requirements where a long run of ducting may be required, there are centrifugal fans, which offer a higher-powered form of air extraction compared to a normal inline fan or through wall fan.
So as you can see there is a range of fans to suit just about all of your requirements. However given this choice it may be a good idea to think about contacting a specialist for advice, as different fans are made for very different purposes.
As an example a commercial kitchen extractor fan would be simply deafening and total overkill for use in an office environment. Yet the same considerations have to be made when choosing through wall fans. If you fit one that is too small for your bathroom or shower room, then it will not extract the damp fast enough, and the mirror will always be unusable after a shower.
The same, if not more so applies when buying an extractor fan for a toilet. A six-inch fan may suffice at home but it will not do so for a toilet in an office that is in regular use.
A good extractor fan supplier will be able to provide advice on ensuring you buy the right one for the job.