Installing an Exhaust Fan

SAFETY WARNING: Some parts of this blog post involves working with live electricity.
Please engage a certified electrician for electrical works, especially if you have no idea what you are doing. Always ensure that power is cut at the DB box to be safe. Test with a test pen before touching any life parts or life wire!

The neighbours agree, too!

We knew we needed our bathroom to be well ventilated. The tiny window and the lack of open space means that the bathroom is very likely to be damp and most. True enough, in December 2019, when the mercury stayed below 27°C for a good month (what joy that was, no?), a wet patch on our floor stayed wet for 2 days! Can you imagine that? Neighbours within the estate reported the same problem:

When I removed the exhaust fan for a minor modification project (we’ll come to that later), I, as fate would have it, needed to go urgently. Over the course of my “business”, I noticed that the toilet was significantly more stuffy than usual. While we knew that the exhaust fan was pulling in air from the room into the toilet, I hadn’t realized it was making the whole toilet less stuffy, too. So, all in all, not only does it help keep your toilet humidity low (and hence less likely for moss and other yucky stuff to grow), it also keeps you a little more comfortable when nature calls.


First, you’ll need to lay the silicon ring around the cutout of the glass panel. Some overlap will be necessary. While I was told by the window installer to apply silicon sealant around the ring, it is not necessary because it wasn’t going to fall and complete air-seal wasn’t necessary.

Going back to the fan – remove the 2 screws shown before fitting the fan onto the glass panel. Make sure you keep the 2 small screws well, because you will need them later!

On the exhaust side of the fan, you will notice that there are 3 features that are shown below. These are the features that holds the fan in place. They are also responsible for making the fan installation a little more complicated.

That brand looks suspicious..

If your window contractor got it right, the opening of the hole on your glass panel would just be slightly larger than the translucent black cover, but not big enough that you can fit the fan through dead-on. The 3 stopper features should prevent that from happening. Here’s a step by step sequence on how to fit it correctly:

Step-by-step visual guide to fan installation (excluding wiring).

Complete the 4 steps above and you’re ready to secure the fascia. Put the 2 screws back in place, connect the wires up (brown to brown, blue to blue, yellow/green to yellow/green) and you’ll be good to go!

Note: the above is only true for dumb switches.


I’m not too sure what the reason is, but I suspect the back-current from the fan (i.e. the current that is generated when the fan turns due to external winds when there is no power flows back into the smart switch) fries the PCBA. Whatever the reason is, it is a known fact – trust me, I’ve been there.

There is, however, a way to use a smart switch with an exhaust fan, but that is a story for another day.

Getting Started

Like all good things, episode 1 comes after episodes 4, 5 and 6… Anyway! The reason why this bit is right at the end because I wouldn’t expect someone to be able to DIY the window. You may have an exhaust fan you’d like to remove for cleaning or replacing, but windows isn’t exactly DIY territory in Singapore. If you’re renovating, then read on:

You’ll need to remove the default windows. Note that exhaust fans are technically not approved by HDB, and for Condos you’re most likely required to get approval from the management. You will need to engage a HDB certified window contractor (tip: you can get it done together with your service yard windows). I would leave a name for you, however the guy who did mine doesn’t do residential jobs (he was doing his friend a favour when he did mine), so I’m not of much help here. What I can tell you is it should cost about $580 (inclusive of 2 x KDK 20WUD fans) for glass. There is a company called D2 Services that provides Acrylic panels – I suggest to stay away from them.

Either way, your window guy cuts the hole, your electrician will install the fan. We bought our own fans from Parisilk at $70 each.

Note: 2019 prices.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.