In this article we'll be looking at a couple of frequently asked questions:
- How long should you run your bathroom exhaust fan?
- Do Bathroom extractor fans use much electricity?
Before we go into detail here are a couple of fans that as designed to ensure your bathroom remains fresh and free from condensation and remove any guesswork.
Tornado ST100HT Silent 100mm Bathroom Fan Humidistat & Timer
Tornado ST100DMEVHT Silent dMEV Continuous Running Extractor Fan
Let's look at the first question.
How long should you run your bathroom exhaust fan?
Most bathroom extractor fans will be triggered by the light switch when you enter the bathroom, with others triggered by humidity levels or movement. When you leave your bathroom and turn the light out, your fan will also turn off unless your fan has an over-run timer function or a humidistat.
Think about your normal morning routine. You step out of the shower and leave the bathroom, turning the light off, and get dressed before rushing off to work. If your fan also turns off at the same time as the light, the remaining humid air will be left to cool and condense on your bathroom ceiling, walls, and surfaces.
It is advised, where possible, to install a fan with an over-run timer option as this will allow the fan unit to continue to run for a pre-set amount of time after the light has been turned out.
It is suggested for most bathrooms that you set the timer to allow the fan to run for 10-15 minutes after the light has been turned off or longer for heavy use bathrooms and wet rooms.
Fans with humidity sensors will of course be triggered when the relative humidity in the room rises and will turn off again when it detects the humidity has dropped below the level the fan is set to detect. Most humidistat fans also come equipped with an over-run timer to ensure the humidity level in the room has dropped sufficiently, some kicking in when the humidity drops below that trigger level while others are attached to the lighting circuit like a regular timer fan.
It is worth noting that you should check with your electrician as to whether you have the required wiring in place to install a timer or humidistat fan unit as these require an additional constant live feed to function.
Now, let's look at the second question.
Do Bathroom extractor fans use much electricity?
Bathroom Extractor fans use very little power to operate, generally consuming between 5 - 36 watts depending on the make and model. This in comparison to a single 100w lightbulb is clearly far more conservative.
There are some fans that can run on a constant trickle flow, these fans are ideal for bathrooms without windows or that are prone to damp and mould. They allow a constant circulation of air throughout the day and night and boost up to a higher extraction rate when needed.
Trickle flow fans are efficient to run as constant use units, and can cost as little as £1.50 per year depending on your suppliers electrical unit cost.
Well I hope you found this article useful.
Thank you for the article. I've often thought about how costly extractor fans are to run and the savings of turning it off vs humidity getting into the house. People should probably use them for longer if they have them. Most helpful!