Check the water pressure. As mentioned above, if it is below 5 bar, then it is the product's quality problem, as in general storage water heaters should be able to sustain basic operation below 5 bar.

And the instant water heater's rated heating power is equal to its power usage only if u keep using it its max (power / temperature knob is always turned to the maximum).

Hence if u are concern about energy usage, but also worry that your instant water heater is not giving u hot enough water (especially during raining season when the water supply is much colder than normal days), better to get higher kW instant water heater.

eg. if u get a 4.2kW but your power / temperature knob is not turned to the maximum, it is equivalent to using the same energy as a 3.6kW instant water heater, yet u still have the option to turn to the maximum to increase heating when u need it. Likewise, if u get a 3.6kW instant water heater, u won't have to option to increase heating further comparing with a 4.2kW instant water heater.

I think most instant water heaters in Malaysia use water flow switches instead of water pressure switches. Brands such as Joven, Alpha, Centon, etc. will state in their specification what minimum / rated flow rate you will need to be able to use the instant water heaters, most commonly it is a CONSISTENT 2 litres / minute water flow, not fluctuating. Anything lower than that (which is already very low), your instant water heater's flow switch might not be triggered / switched on, and it will not generate hot water (but the low water flow room temperature water will still flow through).

U can purchase a water flow meter to measure your water flow rate of the water source that will be connected to your instant water heater, or just get a plumber to check it for u. Make sure you place the water flow meter at the exact height and curve of the pipings to where the instant water heater inlet piping will be, to simulate the exact condition, since different height will generate different water flow rate due to gravity.

Always get certified electrician to handle the electrical connection, and if u need major piping connection works, get a certified plumber to handle to piping part. Just make sure that the plumber check that your water pressure / water flow is sufficient as all water heaters will need a minimum flow rate for it to work, even if the water heater has a built-in pump. If not, install those external pumps like Grundfos to beef up your house's water pressure.


One benefit of buying from e-Commerce sites is that you can refer to product reviews and ratings to provide yourself with an educated estimation on whether the product is good or not, as those people that wrote the reviews are those that actually have experience using those products already.

There is already a thread discussing on storage water heater. U can refer to this one - https://forum.lowyat.net/index.php?showtopi...ost&p=105300393

Like what mini orchard has commented, showing us your installation picture will better help us understand what problems u are facing.

Regardless, just backtrack and investigate which component is slowing down your water flow, assuming your original water source has good water flow, as what u have mentioned.

1. Remove pipings from water source to water heater, double check if your original water source is still strong. If yes,
2. Connect water source to stop valve, remove stop valve from water heater's inlet, check if your original water source is still strong. If no, the stop valve is what slowing down the water flow. If yes,
3. Connect stop valve back to water heater's inlet, remove water heater's outlet hose, check if your original water source is still strong. If no, the water heater is what slowing down the water flow, maybe something stuck inside. Get Midea service team to check. If yes,
4. Connect water heater's outlet hose, remove shower handset. Check if your original water source is still strong. If no, the shower handset is what slowing down the water flow, maybe something stuck inside.

In the situation where the water heater is the same, and constantly set at the maximum temperature setting,

1. Higher water flow = lower output temperature
2. Lower input temperature (eg. raining season) = lower output temperature


So in your case, if you have recently increase your house's water pressure, your output temperature will definitely drop. Also due to the current raining season where input water temperature is colder, the output water temperature will definitely be colder as well.


So if your current ALPHA water heater is not hot enough for u, better to check its power rating (displayed in kW) and get a higher power rating water heater. Higher kW = higher output temperature. In the market these are the usual range (if I'm not mistaken):

3.6 - 3.8kW | The most common ones, ALL water heater brands should have models within these ranges, including ALPHA and PANASONIC.
4.2kW | CENTON models are famous for these ranges.
5.xkW | JOVEN and CENTON have these ranges. Mostly used in colder places such as Cameron and Genting, or condominiums with high water pressure.
7.xkW | CENTON and BEEBEST have these ranges. Mostly installed above the ceiling or under the sink, storage water heater replacement (but definitely cannot achieve output water heater as hot as storage water heater, but way hotter than the lower kW instant water heater ranges).

Yeah 10 years better just invest in a new one.




This is taken from Suruhanjaya Tenaga's guidebook.


Basically all water heaters (both instant and storage water heaters) with power ratings:

Below 5.7kW | should be using 4mm cable (most reputable residential property is following this requirement, while those not reputable ones and irresponsible installers / technicians / contractors will try to save cost and use underspec cables instead, which results in overheated / burnt cables). 1.5mm cable is DEFINITELY wayyy underspec and a big no-no (those used for lightings), and anything between (such as 2.5mm) is not recommended, use it at your own risk.

5.7 to 7.1kW | should be using 6mm cable, and anything lesser (such as 4.0mm) is not recommended, use it at your own risk.

Better to ask the electrician what cable u are currently using or what will he be using for your installation.


Make your decision based on your previous water heater's kW (before it breaks down). If you were previously satisfied with that output temperature, then u can get a new one with similar kW.

Yeah it is the same as all instant water heaters in the market. Output water temperature is affected by:


1. Input water temperature

- the colder the input water temperature (eg. raining season), the output water temperature will be colder as well,

- unless the water heater models have the output water temperature stabilizer function that is found in expensive models.


2. Power Rating

- the higher the power rating, the hotter the output temperature.

- Most common power rating in Malaysia is 3.6kW and 3.8kW (nearly all brands), followed by 4.2kW and 4.5kW (Centon, Deka, etc.), even up to 7kW (Centon, Beebest).

- The higher the power rating, the higher specification is required for your electrical components, eg. MCB, wirings, switch. For example, all water heaters with power rating below 5.7kW u should use 4mm wiring cables, while power rating above 5.7kW to 7.2kW should use 6mm wiring cables (which is much more expensive compared to 4mm).


3. Water Flow

- The faster the water flow, the lower the output temperature.

- Water flow can be affected by:

i. Your original bathroom water flow (eg. condos are usually much faster than landed properties, unless it is installed with powerful booster pump at the water source piping).

ii. Flow restrictor / regulator found in water heater parts such as stop valves.

iii. Shower handset nozzles size and quantity.
Eg. Panasonic nozzles are much smaller than most brands, so overall water flow is slower with shaper spray (sometimes quite painful haha) and nozzles tend to get clogged much faster than other brands and need cleaning, but with the benefit that output water temperature is hotter.
Eg. Joven's shower handset I think has lesser quantity of nozzles compared to other Malaysian brands like Alpha and Centon too, which results in lesser output water spray, but hotter output temperature.


- - - - -


So if you have issue with your water heater's output water temperature being not hot enough, either:

1. Get a new water heater with higher power rating, or

2. Lower your water flow by adjusting your stop valve (most brand's stop valve has a regulator function to reduce water flow), or

3. Get a new shower handset with smaller nozzles or lesser nozzles quantity.

This post has been edited by Selene Yeo: Jan 18 2023, 12:27 PM

Of course it is different. Instant water heater's heat generation has 3 factors, mentioned in my previous post. But regardless, even the most powerful instant water heater available in Malaysia cannot achieve the hot water temperature generated by a storage water heater.

Both instant water heater and storage water heater are different technologies, and they have their own advantages and disadvantages. Comparing both of then is like comparing a plane and a ship.

Many people in this thread are using instant water heaters, including myself, and are satisfied enough with instant water heaters, or hot water is "proper" enough for us.

Even if you go for the hottest instant water heaters available in Malaysia, eg. 7kW ones by CENTON / BEEBEST, those can generated on average about 50°C hot water (depending on water flow & input water temperature), while storage water heater is about 70°C hot water. See the stark differences?

And not forgetting 7kW instant water heaters u will have to reinstall high spec 6mm cable / 40A MCB / 40A switches, which might cost quite a lot, and may end up similar to the cost of installing a storage water heater. Cost vs. output, if u want hotter water similar like your previous storage water heater, then u should have budgeted to install a new storage water heater, not an instant water heater.

And if u take the time to read the thread, there is already a few answers to your question on how to make the output of instant water heaters hotter (also resent to u below), if u decide to stick with instant water heaters.

Usually warranty of a water heater will be voided if the water heater is used with shower accessories not provided by the same brand, with the reason that maybe it will cause complications to the expected output of the water heater. An example, if u buy a standalone rainshower from Shopee, those China made ones usually have much larger nozzles compared to the rainshower set that comes with the water heater, which will give u lower output temperature (large nozzles = larger water flow = lower contact time between input water and heating element = lower output temperature).

So IMHO, better to get the complete set (water heater that comes with the rainshower).

Never DIY repairs for high-risk / high-powered appliances like water heaters, unless you are qualified to do so. Either get the brand's certified technician to service it, or if you are not willing to pay for the servicing fee / spare part replacement fee, then I suggest you to just get a new one.

U can just go on Shopee / Lazada to check the product reviews and ratings from previous buyers, and make an educated decision using those data.

By far I see that CENTON EcoSerene has the best ratings and reviews, this one. Price looks very economical as well, and its 4.2kW, so it'll generate hotter water compared to other brands (other brands r usually only 3.6kW to 3.8kW).

If u have a bathtub, definitely need to use storage water heater, as instant water heater won't be hot enough.

If u are using rainshower, warm water travelling up from the instant water heater to the rainshower head will pass thru the rainshower metal pipings, which cause quite a bit of heat loss. So better to get instant water heaters with higher power ratings (higher power rating generates hotter output water), eg. above 4kW range like CENTON models. I'm using CENTON Serene 4.2kW with rainshower, output water temperature is satisfactory, but do not expect storage water heater kind of hot water temperature.

All instant water heaters between 3.57kW to 4.462kW (which is the power rating range of majority of the water heaters sold in the Malaysian market) have the same requirements according to Suruhanjaya Tenaga's guideline, as shown above. So it is not just 4.2kW, but 3.6kW and 3.8kW too. Definitely recommended to follow, but some people unfortunately chose to save cost and use underspec cables, RCDs, or switches, risking their own lives.

And yes agree with u that plug + socket connection is a big NO for bathroom, also as mentioned in Suruhanjaya Tenaga's guideline, as shown below.



I am using this CENTON Splashproof Connector to replace my existing 3-pin socket (using the same junction box, just replace the front cover), bought from Shopee here.

I remember this Shopee Store Onsenmy has CENTON instant water heater models with power rating in the 5.xkW range and even 7.xkW range too, u can check with them. But do remember higher power rating means u need to use higher specs MCB / RCD, switches, and cables. U can refer to the Suruhanjaya Tenaga's guideline below for the correct electrical components specs to use.




If u don't want the hassle of upgrading your house's electrical components to cater for the higher power rating instant water heater, then just get a storage water heater like this. Storage water heaters are usually in the 3.xkW range or below, so u can use electrical components with standard specs for water heaters, but u might need modification to your piping setup (adding mixer, hot, and cold water pipings).

On the plus side, storage water heaters are definitely way sufficient for rainshower and even bathtub usage, and it is also hidden above the bathroom ceiling, similar like those found in hotels.

This post has been edited by Selene Yeo: Jan 3 2024, 11:07 PM

Last time Beebest has 7.xkW too. But nowadays I don't see this brand in stores anymore, not sure if they have closed down or not.

Reliable or not u can refer to Shopee / Lazada product reviews and make an educated decision based on other buyers' experience so far with the brand.

I used their after sales service before when I undersized cable that is connected to my water heater burned. The CENTON technician took his time to patiently explain to me clearly about the dangers of using undersized cable, and made sure cable setting is compliant to Suruhanjaya Tenaga standard. A very good experience for me.


Comparing these 3, CENTON's advantage is it has hotter 4.2kW heating element while Panasonic is only 3.6kW (though Panasonic's handset nozzles are much smaller, causing its output water temperature to be comparable with a 4.2kW water heater, but spray is much sharper and painful at times, and the smaller nozzle is more prone to get stuck from dirt).

PANASONIC's advantage is its push start button, users who use this before will usually get used to it won't change to use water heaters without push start button.