How Long Should a Bathroom Extractor Fan Stay On For?

Have you recently installed an extractor fan in your bathroom but you aren’t sure how long it should stay on for? No problem at all! We will detail the best amount of time your bathroom extractor fan should stay on for. For those in a hurry here is the answer:

For an average domestic bathroom, a bathroom extractor fan should stay on for between 10 to 15 minutes. This gives it enough time to extract the air in your bathroom, toilet or shower so that there is no mould buildup and the room is ready for the next user.

How long can a bathroom extractor fan stay on for?

The amount of time a bathroom extractor fan can stay on for is usually between 20 seconds to 20 minutes, depending on the extractor fan you have and its different control options. For most extractor fans, this is something that can be configured at the time of installation, usually with a screwdriver.

Depending on your application, extractors fans can be run continuously as well but people usually opt to do this with a fan that has a much lower extraction rate. This would ensure that humidity and moisture in the air is constantly extracted and would benefit somewhere like a busy restaurant toilet that is constantly in use, versus a small domestic bathroom.

Related: Best Continuous Running Extractor Fan

What triggers an extractor fan to activate?

There are a number of different control modules that trigger an extractor fan to activate, they include:

  • Light Switch (light switch activated)
  • Pull Cord (often connected to the light)
  • Timer/Over-run Timer (typically after you turn the light off it activates for a specified amount of time)
  • Humidity Sensor/Humidistat (activates when the room reaches a specific temperature)
  • PIR/Motion Sensor (motion causes activation)
  • Different combinations of all the above (in some models multiple controls can trigger activation)

The most common activation type is via a light switch or timer. The Airflow iCON series (15, 30 and 60), for example, is one of the few extractor fan ranges that lets you essentially “plug and play” different control options to suit whatever mode of activation you’d like, which is great.

Factors that determine how long a bathroom extractor fan should stay on for

There are a number of different factors that will determine how long you should your bathroom extractor fan should stay on for.

  • How often it needs to be activated
  • The size or volume of the room
  • The size of the extractor fan
  • The extraction rate of the fan
  • The cost to run the fan/your electricity budget
  • The level of existing ventilation in the room

These are important factors to consider when thinking about how long you want to keep the fan on for.

Can I leave my bathroom extractor fan on continuously?

As mentioned earlier, it is possible to have your extractor fan run continuously, but it is unlikely to be suitable for a domestic application. This can be done via the wiring as opposed to a control module, like the ones listed earlier. It occurs when you go for a non-timer module fan and connect it to the permanent live wiring configuration. That way it will stay on all the time.


Ultimately, how long you should leave your Bathroom Fan on depends on a number of factors.

For your bathroom, shower, or toilet, 10 to 15 minutes should suffice.

If you feel you need a time outside of these ranges then you have the option to adjust it from 20 seconds up to 20 minutes, and sometimes longer, if required. For wet rooms or larger, heavy-use bathrooms, this may be necessary.


Should a bathroom fan run all the time?

For most domestic applications your bathroom fan should not need to run all the time. If you have a heavy-use bathroom or wet room then it may be necessary to run it all the time.

How long can you keep a bathroom fan on?

Most bathroom fans can stay on for up to 20 minutes or so, though some models can be wired in a specific way to run constantly.

How long should an extractor fan timer be?

Ideally, you want the extractor fan timer to run for 10 to 15 minutes after you have finished in the room – whether this is when you turn off the light switch, or when the room reaches a specific humidity, etc – this all depends on your choice of activation. 10 to 15 minutes is usually enough time in most bathrooms to clear the moisture and extract the air for the next person to use the bathroom, shower or toilet.

When should I turn my bathroom fan off?

You shouldn’t ever need to turn your bathroom fan off. The only time you should turn it off would be if you are trying to repair, replace, or install the extractor fan – for safety reasons. The purpose of an extractor fan is to ensure the air in your bathroom is always being extracted after use so turning it off may mean it won’t be doing its job.

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