Bathroom extraction fans and what you need to know
Bathroom fans are by far the most over looked fixture in any bathroom build or renovation, but if not done properly they will take years off your bathrooms lifespan due to the moisture build up damaging what you can see like Paint peeling, mould forming, mirrors desilvering (linked to a great article from a glass company in case you don’t know what it is) and even cabinetry damage is really bad situations. These are all signs of damage that can be seen, but also mean you are damaging what you can’t see which is the far more concerning part
So, lets get into the 3 things that control a fan doing it’s job and stops moisture build up
Installation
Which is broken down into
Location
Allowing a vortex to form(air to be pulled out by the fan)
Ducting
Extraction power
How much power is needed based on room size
Heat lamps/heated floor(or heating in the bathroom in general)
If the moisture evaporates, none of that damage occurs
Installation
Location - The location of the extraction fan is really important. Think of it just like your rangehood, you don’t just chuck it into the ceiling anywhere. Having it close to where the steam from the shower or even directly above is where it needs to live. Don’t try to balance it between the toilet, those smells are already being dragged up 2 metres and another metre isn’t going to change how long the room isn’t usable (This odourless Toilet with inbuilt extraction fan does though!)
Allowing the vortex
Air doesn’t move in straight lines and also needs to come from somewhere (or you create a vaccum) so when the fan is installed there is a couple ways to do this
allow a 1cm gap at the bottom of the bathroom door for the air to be drawn from
Always have the window open just a smidge
If 1 of these are not done, you are creating a partial vaccum and burn out your fan motor in the process
Ducting
(Eave kits can normally be purchased for about $100)
There is no australian standards saying you must ducting your extraction fan or even have one, this is why it’s done wrong 95% of the time. Always duct any type of extraction to the atmosphere or otherwise you’re pumping all that humidity into your ceiling cavity. It makes no difference at all in summer, in winter though you’re reducing your insultation life span and effeciency
Extraction power
Lets say you have a larger than typical bathroom which is 4 metres x 4 metres and 2.7 metre ceilings, that makes the room 43 cubic metres of air. So a $25 bunnings fan like this will do the job? Actually yeah! As long as the installation steps are followed above. Power is never the issue, it’s always location, vortex and ducting
Heating (Light or flooring)
The whole point of a fan is to take the moisture out of the bathroom, this can also be achieved by heating too. Removing the moisture is to extend the life of the bathroom, so I would always recommend using a heat lamp or heated flooring. Even if you ducted heating in the room, it does a horrible job at heating up the floor which is where moisture naturally ends up. For their cost, they easily give bathrooms additional 5+ years of life span
Your consultant/designer/tradie should be taking the long term use and lifespan of your bathroom into consideration with these small and low cost additions
