If I'm not mistaken, most enamel-coated storage water heaters uses mild steel underneath the enamel-coating.


I believe u can conceal it anywhere as long as that area provides sufficient space, water pressure, and electrical component & wiring that caters to the storage water heater's minimum spec requirement.

But make sure to provide sufficient access opening (eg. manhole) for future maintenance, enough room for the storage water heater's dismantling process or servicing work, or else u will be charged for breaking and reinstalling of your concealed area (eg. plaster ceiling).

This post has been edited by Selene Yeo: Aug 19 2024, 10:41 PM

Potential costs involved are:
- Cutting and replacing plaster ceiling, or making a manhole (recommended for future servicing needs)
- Checking / replacing electrical wiring / components that have been worn off
- Removing old storage water heater
- Installing new storage water heater
- Connecting pipings

Costs vary according to what is needed. Sellers of storage water heaters should be able to recommend u installers, so do ask them for it. But don't expect it to be cheap. U should be spending bout RM400 to RM500+ on average.

Again, don't cheap out and find one installer that is priced super low, as they might not be qualified / certified to install, and u might end up with dangerous leaking (hot water) pipings, or worst electrical shock hazards.

Few points to consider when choosing between getting a storage water heater for each bathroom, or just getting 1 to share between few bathrooms:

1. Heat Loss - The further the hot water are required to travel (aka bathrooms that are further apart from the storage water heaters), the more heat loss since hot water has to travel further.

2. Waiting Time - The further the hot water are required to travel (aka bathrooms that are further apart from the storage water heaters), users will take a longer time to get the hot water after turning on the mixer.

3. Under-utilized Hot Water - Getting only 1 x 90L to share between few bathrooms while not fully utilizing the hot water is generally not efficient, since u mentioned that the extra bathrooms won't be utilized most of the time. The more efficient way is to install 1 for each bathroom with a smaller capacity storage water heater, and only turn on the storage water heater at the extra bathroom only when it is required.

4. Servicing Down Time - After a span of time, if u have multiple storage water heaters and 1 storage water heaters goes down (out of service), at least u still can use others. If u only have 1 for the whole house, and that one goes out of service, u will not have hot water to shower until it is fixed.


My suggestion is to get 1 storage water heater for each bathroom (unless they are right next to each other), and get an instant water heater for that extra bathroom that is not in used most of the time.

For master / powder room / doggie shower room / jacuzzi, suggest u to go for 90L, since there's a jacuzzi involved.


Underutilized means on an daily basis, maybe at most u will only be using 50L of hot water, but u are boiling 90L of hot water. So u are not fully utilizing the remaining 40L of hot water.

Disadvantage is you are wasting electricity, but not significant if u are constantly using the hot water in the tank daily.


IMHO, no issue if u do not want to turn it off if u are using it on a daily basis. If the switch is kept turned on, the thermostat in the storage water heater turns on and off to keep the hot water in the tank (usually at bout 70 to 80°C, depending on brands), but temperature doesn't drop much due to the insulation around the tank to keep the heat in. If u turn off the switch, this thermostat turning on / off to keep the temperature constant won't happen, n u will save more energy at that point of time, but when u turn it on again on the same day, u have to wait for the water to boil again and require the close to the same amount of energy to boil it up. So the energy saving u'll get for turning off the switch is insignificant (again, if u use it on a daily basis), with the downside of having to wait for the water to boil up again.

But do turn it off if you won't be using it for a period of time, eg. the one in your guest room, or if u are away for a holiday.

Doesn't look like its SIRIM and Suruhanjaya Tenaga certified. Do not use, for your own safety.

Do u mean your wall plug is outside of the bathroom? Then u should replace that wall plug with a switch instead and u do not need the water heater connector, since the water heater connector does not have an ON / OFF switch.

Just make sure your switch specification and your electrical cable size specification is correct, as stated in the Suruhanjaya Tenaga guideline table shared above, according to your water heater's power rating (kW).

Product price, installation price, servicing / maintenance cost, all I would say instant water heaters are generally cheaper than storage water heaters.

It is also the fact that storage water heaters are usually installed above the ceiling (plus hidden behind plaster ceiling) while instant water heaters are usually installed at just slightly above eye level, which makes installation and servicing for storage water heaters much more tougher, requires more manpower, and with a higher risk of injuries for the technicians, compared to instant water heaters, hence the higher cost.



U can try external pumps like Grundfos (link here: Shopee / Lazada), but do note that they are very strong and will give u very high water pressure, strong enough to burst / wear out your water piping joints.


On how external pumps affect instant water heaters:

1. Higher water pressure / flow = lower output water temperature | So u might want to get instant water heaters with much higher power ratings than your usual 3.6kW ones to compensate for the output water temperature reduction due to higher water pressure, such as this CENTON Serene Highlands with 5.4kW (link here: Shopee / Lazada). If even 5.4kW is not hot enough for u, then u better stick to storage water heaters. Also note that with higher power rating, make sure to use the higher spec electrical components and wiring (4mm cable, refer to Suruhanjaya Tenaga guideline below). And never ever use 3-pin socket to power your water heaters.



2. Risk of Damage | Instant water heaters are usually equipped with plastic tanks (as opposed to storage water heaters that use steel tanks), hence cannot withstand water pressure more than 55psi / 3.8bars, before they leak / burst. So minimize the output power of your external pump to prevent damage to the instant water heaters. And make sure the stop valve is installed at the instant water heaters' inlet, not outlet, to protect the instant water heaters from excessive water pressure when not in use.



No reason u can't, but keep the external pump pressure to not more than 55psi / 3.8bars to prevent damage to the instant water heaters, as stated above.



1. Warranty | Your instant water heaters' warranties are usually voided if u don't use the shower accessories provided with the instant water heaters.

2. Lackluster shower experience | Aftermarket rainshower set usually have much larger nozzles (meant to be paired with external pumps with much more water flow) compared to those provided with instant water heaters (meant for slower water flow). So if u use instant water heaters and their built-in pump with aftermarket rainshower (without external pump), u will get lackluster water flow, worst case water won't even flow out of some of the aftermarket rainshower's nozzles.

3. Piping compatibility | Aftermarket rainshowers usually come with a mixer (to mix cold and hot water, eg. to be used with storage water heaters). Instant water heaters' output water temperature is not hot enough to require u to mix cold water, so u will have to do some piping work to close 1 of the mixer's inlet point.

This post has been edited by Selene Yeo: Dec 14 2024, 09:53 PM

Unless u get the exact same instant water heater model as your current defective one, u will have to expect new holes to be drilled. If you are paranoid about damaging internal pipings, get the piping schematics from your management office / developer.


This is a common practice amongst installers. In terms of warranty, it is a grey area I guess - if hole is small and not causing any waterproofing issue or damage, then it shouldn't be an issue (if the hole is too big, water or maybe insects might sipped in and cause damage).


Suruhanjaya Tenaga guidelines and all instant water heaters' instruction manuals state that all water heaters below 5.711kW power ratings need to be installed with 4mm wire. You are taking your own risk if u do not comply, and might face issues with warranty / insurance / liability claims if (touch wood) incidents happen. Especially true if your wire is wayyy under-spec'ed, eg. 1.5mm wire, definitely prone to electrical / fire hazard and risking the lives of the users.


Don't expect instant water heater's built-in pump to give u super powerful water flow like those external Grundfos / Tsunami water pump kind. If your bathroom's water flow is already fast, u may not even notice any differences after installing an instant water heater with built-in pump; but if your water flow is slow, then yes u will notice a difference.

If you have the budget, then no harm getting an instant water heater with built-in pump. Get those with pump that can be controlled / turn off, as some instant water heater models may not have the function to turn off the pump during showers.

Side note, if there's extreme water disruption (not water at all), having a built-in pump will not help at all, since there is no or minimal water to pump in the first place.


I've got a CENTON Serene too, got it online as it is definitely cheaper than physical stores (link here - Shopee / Lazada). I chose to go with CENTON because of their impressive 5 star ratings on Shopee.

Serviced once because my lousy installer (totally my fault for finding a cheap one) didn't tighten the wire inside the water heater's terminal block properly, causing it to burn / melt. CENTON's technician took the time to explain to me in detail what was wrong with my water heater, very satisfied with their service. It is still working well till this day, and it has been about 4 years+.

Most electrical appliances stores or online stores should have installers to recommend to you. I purchased my water heater from this Shopee store (link here - https://s.shopee.com.my/40PwhHfyVj) and they even recommended me up to 4 installers within Klang Valley for me to compare installation prices with.

It means that your original water pressure (without the water heater's built-in pump) is already strong, close or even surpassing what the water heater's built-in pump can generate.

Note that regardless of whichever water heater brands u purchase, water heaters' built-in pumps are way smaller in comparison with the lights of external booster pumps, such as those Grundfos (https://s.shopee.com.my/BDMfj7nW6) or Tsunami (https://s.shopee.com.my/1B6Sj91TNJ) which cost way more as well and way more powerful.

So for example, if your house has one of these external booster pumps installed at your main water supply, u will not feel any difference between turning on and off your water heater's built-in pump during showers.

Correct. Similar reasons why external booster pumps (or basically houses / condos with high water pressure) are normally paired with storage water heaters (example here - https://s.shopee.com.my/9zhBPf4sNC) rather than instant water heaters, since storage water heaters can generate much hotter water.

Higher water pressure / water flow equals to lesser contact time between incoming water and the instant water heaters' heating element, hence lesser heating which then equals to lower output water temperature for instant water heaters. Hence like what u say, if the water pressure is higher than average, then regular instant water heaters won't be powerful enough to heat up the incoming water.

I am assuming you are referring to instant water heaters, not storage water heaters, correct?

Firstly, all SIRIM certified common instant water heaters should have a thermostat to turn off the water heaters if the output water temperature exceed around 50°C to 55°C, and very seldom this thermostat will malfunction.

Next, the instant water heater's output water temperature is affected by:
1. Inlet water temperature | The lower the original water source's temperature, the lower the output water temperature.
2. Power rating | The higher it is, the hotter the output water temperature (but higher electrical components' specs required).
3. Water flow | The higher it is, the lower the output water temperature.

The most logical possibility is that your water flow is very low (but still sufficient to turn on your water heater's flow switch), but your output water temperature is still not high enough to trigger the thermostat to turn off the water heater.

Also, test the water heater's input water supply to see if it is originally hot or not, as maybe for some reason it is using a water source different from your basin (eg. directly from your water tank that is under the hot sun for the longest time). This test is easy to perform, just quickly do it to rule out this possibility.

Based on your picture, it does look like leaking. The only way to confirm is to get a JOVEN technician to verify. If it is really leaking, it is usually close to impossible to repair, and more cost worthy to just get a new one.

With my limited info, I believe currently there are 2 types of storage water heater tank technology available in Malaysia,
a. Enamel-coated tank technology - newer technology, better leak resistance, and cheaper. CENTON and ALPHA brands are using this new technology.
b. Stainless-steel tank technology - old technology, more prone to leaking, and more expensive. JOVEN and ELTON brands are using this old technology.

For your new one, I suggest u to get one with the enamel-coated tank technology, hence better leak resistance compared to your current JOVEN one that uses the old stainless steel tank technology. CENTON is a good choice, as if u do a quick search on Shopee / Lazada, this CENTON storage water heater (link here) looks like the best storage water heater on Shopee with the highest sold count and with the most 5 star reviews as compared with other brands. U can read the reviews to make an educated decision on whether to proceed with your purchase or not.

Just a heads up too, there's a few noticeable issues with your current installation:
1. U didn't install Isolation Barriers at both inlet / outlet, compulsory as per the Suruhanjaya Tenaga guideline (screenshot below), increasing the risk of being electrocuted.
2. U didn't connect a discharge pipe to your Pressure Relief Valve. Water (and possibly hot water) might get discharge from the Pressure Relief Valve when there's abnormal high pressure spike, and will flow out directly below it, damaging the ceiling directly below it / endangering anyone below.




I believe all storage water heaters, regardless of brands have sufficient insulation to keep the water in the tank hot throughout the day, like a thermoflask (eg. when u heat it up in the morning, if it is unused, it should still be hot enough for shower at night with minimal heat loss thanks to the insulation). This shouldn't be the cause of the leaking.

All SIRIM certified storage water heaters also should have thermostats that will auto cut off the heating (electricity usage) when the water in the tank reaches a certain maximum temperature and it will auto on back to heat up the water when the temperature drops to a certain minimum temperature (via heat loss over time). Hence, storage water heaters will not continuously heat the water even if u keep the switch on, and no harm just keeping the switch on, unless you are away for holidays. Storage water heaters' electricity usage will definitely be higher than instant water heaters, since their output water temperature is wayyy higher (laws of thermodynamics), but I don't think it will be drastic enough to affect your electricity bills as compared to appliances like fridges or aircons.


IMHO all these energy savings are just plain marketing / nice to hear. Heating technology are already quite mature for the past decades (as mentioned above by @Hastebreak), and I believe no one has actually did a proper test to verify these marketing claims. What should matter more is the tank technology and the likelihood of leakage, as shared above.

This post has been edited by Selene Yeo: Apr 2 2025, 11:27 AM

Usually I'll just ask the Shopee / Lazada sellers I purchased from to recommend me an installer. The Shopee seller from the link I shared earlier (here) should be able to recommend u one, with such a good sales volume I expect experience sellers like these to have some installers' contacts.

Just curious, do u know if your JOVEN storage water heater that was installed without the Isolation Barriers was provided by the developer, or it was installed by the previous owner? If it was provided by the developer, then that's quite bad, as the same installation mistakes may occur for the whole township / condo units as well. Best to give your neighbors a heads up if that's the case.



This post has been edited by Selene Yeo: Apr 3 2025, 12:13 AM

Not too sure what's the market price for storage water heaters' installation, but it is definitely expensive (sometimes even close to the price of the storage water heater itself), as storage water heaters are very heavy and sometimes multiple installers are required for larger capacity ones, plus the risk of injury due to the installation height and the appliance's weight.

I know people who had opt for way cheaper installers (eg. unlicensed foreigners), which ended up badly regretting their decision as similar wrong installations like your current storage water heaters may occur, some even damaging their storage water heaters beyond repair even before using for the 1st time (such as installing it in an inversed direction, or turning on the switch before water fill the tank, both causing dry burn in the tank due to the heating element heating air rather than water).

IMHO, don't cheap out on high risk appliances' installation cost.


Best to get it checked and fixed if unsure.

Most likely because your water flow is too strong for the water heater to handle.

Your instant water heater's output water temperature is affected by:
1. Inlet water temperature | The lower the original water source's temperature, the lower the output water temperature.
2. Power rating | The higher it is, the hotter the output water temperature (but higher electrical components' specs required).
3. Water flow | The higher it is, the lower the output water temperature.

If I am not mistaken, your Toshiba model (and most, if not all Toshiba instant water heaters) are only 3.8kW. In comparison, other brands like CENTON, DEKA, RUBINE, etc. are higher, in the 4.xkW range.

And if your water flow is high, your Toshiba water heater will not be able to achieve the temperature that u want, even at maximum capacity. Hence, the blinking is to notify u that it is already at this maximum capacity and cannot achieve the temperature that u want.

If u want to achieve higher output water temperature, try lower the water flow and the output water temperature should increase slightly.

Whichever valves u use to control the incoming water, make sure to also install the stop valve that comes with the instant water heater, as it usually have a filter mesh to prevent dirt and particles from entering the instant water heater and causing damages internally.


Dry burn will only occur if u didn't let water run thru the instant water heater before switching it on for the first time when the heating element tank does not have any water inside, hence the heating element is heating up air, causing dry burn. Once u let water run thru the instant water heater for the first time, there will always be water remains in the heating element tank as long as u do not dismantle the water heater (eg. for servicing, and the water inside the heating element tank is poured out), and the heating element will not be heating up air since there's always water inside (unless the heating element tank is leaking due to defects), hence dry burn will most likely not happened.

Currently there are 2 types of storage water heater tank technology in Malaysia,

a. Enamel-coated technology - newer technology, better leak resistance, and cheaper. Brands such as CENTON, ALPHA, and MIDEA are using this technology. CENTON and ALPHA has higher power rating (3kW), while MIDEA is half of that, which means MIDEA's heating speed is much slower compared to CENTON and ALPHA.

b. Stainless-steel technology - old technology, more prone to leaking, and more expensive. Brands such as JOVEN, ELTON, and THETA are using this technology.


No doubt MIDEA's price might be cheap (Shopee link here), but requiring to wait double the time for it to heat up might be a bit of an inconvenience.

My suggestion is to go for CENTON, cheaper than other Malaysian brands; and also a quick scan on Shopee shows that this model is the highest selling storage water heaters and the most 5-star product reviews on Shopee (Shopee link here).

An instant water heater's output water temperature is affected by:

1. Inlet water temperature | The lower the original water source's temperature, the lower the output water temperature.
2. Water flow rate | The higher it is, the lower the output water temperature.
3. Power rating | The higher it is, the hotter the output water temperature (but higher electrical components' specs required).


I am assuming:
1. Your inlet water temperature should be the same since you are replacing your NATIONAL instant water heater with a new PANASONIC one in the same bathroom (hence possibly same water supply and piping connection).
2. Water pressure into the water heater is close to the same (since its the same water supply).

Hence, the remaining possible explanation is that your PANASONIC instant water heater's power rating (should be 3.6kW) is lesser compared to your old NATIONAL one. If that is also not the case (eg. if your NATIONAL instant water heater's power rating is equal or lesser than your new PANASONIC one), then I have to agree with ceo684's hypothesis, that your new PANASONIC instant water heater is giving you higher water flow compared to your NATIONAL one, what's more the new PANASONIC one comes with a built-in pump as well, which help boost the water flow rate.


So how to solve the issue you are facing? - Get an instant water heater with a much higher power rating.

PANASONIC instant water heaters' power ratings are usually only 3.6kW, one of the lowest in the market, and their their heating performance is compensated by also having one of the lowest water flow rate shower handset in the market (with very small nozzles that drastically reduce water flow rate, but with the downside of having sometimes painful sharp needle spray if the water pressure is high).

If u want something hotter, u can try:
a. one of the hottest instant water heaters in the market, CENTON Serene Highland with a 5.4kW power rating (usually meant for highlands like Genting or Cameron), Shopee link here, or
b. something in between, DEKA Miizu / Aquas with a 4.5kW power rating, Shopee link here / here.

This post has been edited by Selene Yeo: Jun 29 2025, 12:52 PM

You can read the reviews on Shopee and make an educated decision based on that. Here are the Shopee links:

- CENTON Storage Water Heater here
- RHEEM Storage Water Heater here


Based on a quick scan on Shopee, the best-selling (number of units sold) storage water heater on Shopee looks like is CENTON, even more than JOVEN or MIDEA, and they also have the highest numbers of 5 star reviews. Guess that speaks for itself.