Just out of curiosity. This is more of seeing if it is possible. In one of our bathrooms in our house we have a stacked 3-gang switch. One switch for the lights, one switch for an exhaust fan, and one switch for a heater, though that is not used currently at this moment.
I have not been able to see if there is any kind of relay or smart switch(s) that can be used for that setup. Any input. given it is in a bathroom.
There are plenty of 2-channel relais at least, e. g. I am using Shellys https://www.shelly.com/products/shelly-2pm-gen4 which can be easily integrated into Homeassistant
Assuming your switches are outside the bathroom and not in direct contact with humidity, you should be mostly* fine to use a 3 gang smart switch.
*By mostly, I mean that the lights & exhaust fan are definitely within the load thresholds of smart switches. The heater might be borderline or too much load, so you would need a contactor (a relay, basically) between the smart switch & the heater.
If those switches are inside the bathroom, I wouldn’t recommend anything except maybe smart relay modules hidden in the ceiling, one of which can be a 2 relay module and the other a single relay module rated for at least 25% over your heater load.
The switches are in the bathroom. I am US based I forgot to mention that in my initial post.
I’d play it safe and get smart modules then. No need to risk using a smart switch in a humid environment unless it specifically mentions it’s IP rated.
How much current does each device draw?
Amps or watts is fine for your answer, assuming single phase 110volts AC supply.
Post a photo of your existing switch. Is it a standard wall switch or have any special waterproof rating?
I was generally thinking along the same lines as ShadowFist (leave the “real” switches alone and use a smart module).
However it might be worth talking to an actual electrician (I am not one).
In all likelihood you could use low voltage through the switches themselves (so probably not an electrocution risk), however the mains voltage side (of the smart module) may not have GFCI protection (unless the module includes that) in such a scenario.
My concerns would be two fold:
Yes, there are switches where a dripping hand invites getting zapped, and a public bathroom that is hosed down twice a day for cleanliness, but I suspect this is an ordinary household bathroom, and a mains supply protected by safety switches.
Touch switches that are waterproof was my first thought, but switching capacity was my first concern. Hence asking for current draw.
Also the question to post the photo of what is currently there and presumably safely working for a while…
“Bathroom” or toilet room? Asking for those non-US readers.
While I am not entirely sure how else it would be described in other countries it contains the bathtub and toilet, Whatever that may be referred to as around the world I am not sure. Since asked here is a picture of the switch configuration. I am fairly certain it is just a standard switch, but I am not 100% certain about that.
Thanks for the photo. 1 pic=1000 words.
Given the ‘modification’ to the switch surround and lack of waterproofing sealant, would it be safe to assume electrical shock from moisture is not an issue?
Do you have some form of electrical leakage current protection for your home power supply? (Alluded to as GFCI by David, but known as RCD, RCBO elsewhere)
Can you post a photo of the light, fan and heater they connect to, including a rating label of the heater if one is visible on the side, or at least the make and model.
Do you have a neutral behind those switches as well?
I know about a lot of the devices available US & EU… Moes is one of the only devices I think could fit what you are looking for.
I have an extra Moes WiFi Star Feather Series Smart Switch - these are smooth sealed touch panels so no ‘open’ toggles for water to get in.
Alternative is to install smart relays behind the mechanical switch you already have installed.
I have a bunch of extra relays and a Moes (all new), LMK if you want anything, I’ll give you good deal 
Those Moes waterproof switches could probably be a dropin swap, as long as the neutral and current load issues are allowed for. If the new switch thickness is a little too high or low, a chisel job on the surround and some flexible sealant would leave a nice finish.
None of my family has mentioned anything about it, and when we bought the house we had a house inspection done and they did not mention about it being a safety risk. Of course that was like 10 years ago and I know electrical code changes quite a bit.
I do not know of electrical leakage current protection in our home power supply. Unfortunately I am unable to get a rating on the heater due to the whole unit being mounted in the ceiling.
I have not pulled the switches of so I do not know if there is any neutral wires back there.
Image of light, fan, and heater unit included.
find out what fuse amp rating you have going to the bathroom. That will tell you a lot. You need to pull out the unit and read the label also.
No one can safely make recommendations without knowing the details of all the items involved in the circuit. If you are not comfortable DIYing it, call in a licensed electrician.
A reverse image search on Google lens shows this unit:
If so, it requires 1500watts power for the heater, plus a tiny bit more for the light and fan.
Check if the Moes switch will drive it. 1600watts at 110volts is around 15amps draw. (Ohm’s law with rounding)
Your electrician will be able to confirm if a neutral is present at the back of your existing switch and if the Moes unit (often only rated at 10amps and needing a neutral connection) is suitable.
Your other choice is to have the Moes switch for the heater to drive a contactor/relay to act as a ‘current booster’ to switch the appropriate current. You can even fit it out of the way in the ceiling space adjacent to the heater, rather than try and shoehorn things behind the switch. The power requirement for the light and fan should be less than 200watts each (under 2amps) so usually switches rated for lights (around 2-3amps) should be suitable. This way you could re-use your existing wiring without having to pull out and run new wires in the wall.
There are many glass surface waterproof switches on the market. Finding a suitable one is sometimes a challenge.
Oh, please consider the GFCI safety switch - how valuable is your life, that of your family, and home?
Often bathroom ceiling combo units are fitted aftermarket, so the existing light circuit power supply to the light switch is lazily repurposed to power the fan and heater also instead of coming from a suitably fused and rated power circuit. Hence no markings on the electrical board and no certainity the fuse rating is still appropriate, or the isolator switch for power is actually switching off the heater circuit if the lights remain powered.
A real gotcha for DIYers - never assume the electricals are wired properly unless you did everything yourself.
Trust, but verify!
I didnt think we needed to parse all the different possibilities for his given situation… yea, they could have wired with bare copper, or 22 gauge or…or…or. just pull the stuff out and find out
All likely situations, based on my experiences in examining demolitions, collapses, and fire damaged dwellings. It is amazing what a bit of drywall can hide. The spiderwebs in the photo confirm this is not a recent installation.
The ceiling units often have half turn mounting toggle bolts and if heavy it can fall on you as you take it down, or be unexpectedly lopsided if balancing on a kitchen chair instead of a stable platform. Depending on how long the wires are and how well the connectors were tightened, you could have a swinging object hit you on the head or knock you sideways. All units come with fitting instructions, but I don’t recall seeing any removal instructions, ever.
The wiring colors are often wrong as you need multiple wires snaking into the ceiling, so often the black wires are reused for the extra active you need instead of red. Faced with two red and two black in the ceiling, which is the three active and one neutral for this circuit, or are the neutrals switched with only one active (both will theoretically work)? Why buy ten feet of expensive four core cable if two cheap two core cable runs will do the job? This shortcut is even used by a lot of electricians. Very common.
A meter or circuit tester should be used to verify live wires.
Call the sparky if you’re not sure. They (too) have seen it all.
