Hi all.

I need some clarification on the electricity consumption for water heater at my condo. Of recent, I noticed from the TNB app, my daily usage bill seems to keep increasing everyday. It is worrying, eventho my usage is pretty much the same. I have little appliances in the house.

One of the possible culprit that I suspect is the water heater. I don't know how to describe the type but my unit uses (I believe) the central water heating - where I have to turn on the switch outside of the toilet to get the hot water.

Now, my question is:

1. Do I turn ON only when I'm using it? Turn off after OR it is fine to leave it on (only turn off when away from home very long). Because I read somewhere, I can just leave it ON, because it only consume electricity when the shower is ON - when the water run thru the heating rod or something.

2. How do I figure out which type the condo is using? How do I check?

3. If turn off and on, will it use more electricity since it requires the water to be heated first?


I strongly believe other usage not effecting the bill - cause I only use 1 aircond with 1 hp at night for 7 hours. The rest is just fan, charging gadget, LED lights and fridge. Kitchen appliances rarely use.


Please help for those who knows this matter. Thanks a lot!

Check first what type of water heater you are using. Instant water heater or tank type.

How do I check that? I'm not exactly sure.

This type is it? The one that hide above your ceiling

https://www.joven-electric.com/my/products/...jsh-series.html

climb up open the ceiling panel, see what brand and model the tank

turn off when not using. Turn on 5 min before shower will do. Check the seal of your refrigerator, water heater won't suddenly consume large amount of electricity. Maybe be is also due to weather is hot, so AC work extra to cool down the room.

The tank type has a cutoff, if you leave it on all the time it only turns on the heating when the temperature drops below the set point.

I have a screenshot of mine from Home Assistant that should illustrate what I mean, I leave mine on all the time.

BTW mine uses a lot of energy because its a 90L tank, which is way overkill ... last time listened to the contractor who recommended this size but I think for my double storey with 3 baths even 30L would have been enough.

I have to check first and climb the ceiling.

Ok I will do that when I'm home

But mine is a condo. So I'm not exactly sure. Shouldn't mine uses the condo's tank?

If you got a switch it should mean you have a small tank in the ceiling of the bath.

Same principle just smaller size.

Based on your reply, meaning mine is tankless heater? And this suggest that I have to turn off when not in use to save electricity consumption?

Let me know if my understanding is wrong.

Just take a photo of your shower area. It will show whether you have a instant heater or a tank type. Funny that you cannot differentiate between the two.

Sorry that I don’t know. Not well versed in this matter. Here’s the photo of shower area. There’s no water heater unit


Attached thumbnail(s)

I have checked and confirmed that it is this type as per your link. What’s your advice?

Tank water heater will consume more. It heats up the water when the temp is below the threshold.

Instant only consume during first 10 mins. After that, very little.

After my WH died, I gave up replacing it. Now just bath using cold water. Nice and cooling. Of course, don't use the AC immediately. Wait like 30 mins then only turn on the AC.

You need to turn the switch OFF when not using

As the unit aged it will spoil fast so to prolong its lifetime best to switch off

Mine last more than 15 years and when I told the shop they say it’s impressive dy. Most start to spoilt at 6th year onwards

Ok got it. Thanks

Ok understand now. I should turn on only when showering. The reason why I turn on all the time was because someone told me it is more energy efficient and turn on/off all the time would spoil it.

I guess I got a wrong advice. Thanks for your input

Perhaps you can use the tank type until it finally konk out and change to instant water heater which to me is more practical, uses electricity only when water goes through the magnetic switch and hot water flows almost instantly. I guess the tank type is more when you need hot water for whole house such as kitchen also.