Eager to buy a new instant water heater and not sure what you should be looking for? Firstly, check out part one of this article. Then, understand that there are basic features in every single model, ensuring you are safe while taking a nice hot shower.
These include:
- splash-proof casing – prevents water from getting into the circuits. It should be rated as IP25 standard.
- circuit breaker – cuts the power within 0.1 seconds if it detects an electrical leakage.
- rust-free heating elements – prevent a buildup of rust or sediment that could catch fire.
- surge protection – protects the system from lightning strikes and current leakage.
- flow sensor – enables the heater to keep working even with low water pressure. It also shuts off the heater if the water flow is too low, to prevent overheating.
- non-conductive hose – since 2000, instant water heaters in Malaysia have come with non-conductive hoses. Older models may have used stainless steel hoses – an electrocution hazard.
- thermostat cut-off – cuts the power in case the temperature goes above 75°C, to prevent scalding.
- improved circuit breakers – older models used an earth leakage circuit breaker (ELCB), but newer models use a residual current device (RCD) or residual current circuit breaker (RCCB), which are much better at detecting electrical faults.
To pump or not to pump?
Nobody likes a dribbling shower. Some residences, such as low-level condominium units or landed property, suffer from low water pressure.
Water pressure tends to run even lower when it goes through an instant water heater, as the water needs to flow through the heat exchanger. This is unlike a storage water heater, where the water is already pre-heated and flows directly to your showerhead.
To counter this effect, many instant shower heaters come with a built-in pump to force more water through the showerhead. There are two types of pumps:
- AC pump – adds much more water pressure and is suitable if you want a rain shower that delivers a lot of water at once. However, these pumps are noisy when in use.
- DC pump – adds comparatively less water pressure than AC pumps, but it is suitable for regular showerheads. DC pumps are much quieter and usually more efficient.
An instant water heater with a pump could double the cost of the heating unit. So you don’t need to spend money on one if your water pressure is already good enough, or if you already have a pump installed for the entire house.
Monthly costs
How much does running an instant water heater cost per month? Here’s a simple calculation for a small family with one child. Assume each family member takes an eight-minute shower every day using an instant water heater:
Electricity cost
- Total shower time per month = 8 minutes x 3 people x 30 days = 12 hours
- Typical instant water heater = 3.6kW
- Total energy usage per month = 3.6kW x 12 hours = 43.2kWh
- Malaysia energy tariff = RM0.218
- Total energy bill per month = RM0.218 x 43.2kWh = RM9.42 monthly
Water cost
- Total shower time per month = 8 minutes x 3 people x 30 days = 12 hours
- Typical water flow rate = 5 litres per minute
- Total water usage = 3,600 litres per month
- Malaysia water tariff = RM1.38 per 1,000 litres
- Total water bill per month = 3,600 litres x RM1.38 = RM4.97 monthly
If you add the electricity cost of a DC pump (36W), it would increase the bill by 10 extra sen per month. With an AC pump (120W), it would increase the energy bill by 30 sen per month.
Installation cost
The cost of installing an instant water heater ranges from RM80 to RM150 right out of the box. This assumes no new piping is needed, and power supply is readily available.
This article originally appeared on Recommend.my – Malaysia’s #1 Home Improvement Services Platform. Recommend.my offers a safer and more convenient way to hire the best home improvement and home maintenance professionals. From flooring to interior design to air-conditioner servicing, get access to thousands of the best local contractors and professionals at your fingertips.