if the original water flow is already very slow, i think it will barely make a noticeable difference.


Instant water heaters usually require water flow of at minimum 2 litres / minute to turn on, regardless of whether they have built-in pumps or not. So if your existing instant water heater is currently not able to operate due to low water flow, getting a new instant water heater with a built-in pump will not solve your problem too, since the water heater is still not able to be turned on.

But if assuming your bathroom has at minimum consistent 2 litres / minute water flow, yes water heater with built-in pumps will slightly increase your water flow. A water heater with built-in AC Pump is stronger than built-in DC Pump, but AC use more electric, is noisier, and has a shorter lifespan. N instant water heater's built-in pumps are small too, so don't expect hotel-like water pressure, just a minor increase in water flow.

Best option is to get a booster pump like Grundfos (example here: Lazada/Shopee) that is installed at your main water supply, to boost water pressure throughout your house.


Agree with @keanutan's explanation above. The older the water heater, the higher potential it has more dirt / scale buildup on the heating element surface, hence minorly reducing heating efficiency. This is especially true since your angle valve doesn't look like it has a mesh filter to reduce larger dirt / particles from entering into the water heater. Your water heater definitely looks more than a decade old, good time to change if u want an upgrade.

Since your instant water heater is older than millennials, u might want to double check and make sure your bathroom electrical infrastructure is up to standards when reinstalling a new instant water heater.




1. Use the correct cable size | most common instant water heaters in the market have power ratings between 3.6kW to 4.2kW, which means u should be using 4mm² cables to connect to these water heaters, according to the Suruhanjaya Tenaga guideline table shared above. Under-spec cables (especially those below 2.5mm²) might melt / catch fire. A good brand to go for is Fajar Cable. U can get the 4mm² cables here - Lazada / Shopee




2. DO NOT use plug + socket connection in the bathroom | They are not water proof & increase your risk of getting electrocution, and the 3-pin plug fuse might burn, especially for higher power water heaters, eg. brands like Deka & Rubine now have higher powered 4.5kW instant water heaters, which increase the chances of 3-pin plugs to burn if used together. U can overcome these electrocution and fire risk by either connecting the cable directly to the water heater without going thru and plug + socket connection, or replacing the 3-pin socket with a water heater connector using this same junction box. U can get the water heater connector here - Lazada / Shopee




3. Make sure there is a 10mA RCCB / ELCB for your water heater's electrical connection | As stated in the Suruhanjaya Tenaga guideline shown above, and as shared by @mushigen. Its purpose is to protect u from dangerous voltage in the event of short circuit / electrical overload. Here are some RCCB brands u can get:

- Schneider | Lazada / Shopee
- Hager | Lazada / Shopee
- ABB | Shopee