Choosing Instantaneous vs Storage Water Heaters


Which heater is for you and your home? Ask yourself which is your priority...cost and space saving or showering pleasure...

If space is limited and a single water line is provided like in some condominiums or old houses, a instantaneous water heater is a good choice. If you've invested in a good quality bathroom fixtures and fittings, getting a storage type water heater is more ideal.

Here are some facts and comparison between the two...

Energy consumption:
* wattage may vary depending on brand

1. Instantaneous water heater:
-3.5 kilowatts for single point water heaters
-6.5 kilowatts for multi point water heaters

2. Storage type water heater:
-2.5 kilowatts for 8-26 gals. or 30-100 liters
-4.5 x 2 kilowatts for 40-50 gals. or 152-190 liters
-5.5 x 2 kilowatts for 65-120 gals. or 247-456 liters

Advantages of Multi Point / Single Point Water Heaters
(single point heaters have only one line outlet and usually includes a shower set while the multi point is for 2 outlets, has a higher wattage & can be used for both the lavatory and shower but not recommended for bathtubs)

1. instant heating of water (therefore no pre-heating required and heats only exact amount consumed)
2. saves on space - small and therefore can be located under the sink or beside the shower
3. saves on piping because you only split hot and water pipes starting from the water heater
4. installed only on selected areas of the house or for public and industrial washrooms where hot water is needed on lavatories only.

Disadvantages of Multi Point / Single Point Water Heaters
1. sensitive to water and pressure fluctuation
(too high a pressure will not heat the water properly, too low and the heater shuts down so as not to overheat the unit)
2. distance of heater to mixers should not exceed 3 meters or will result in heat loss
3. reduces water flow in half (not recommended for rain and massage showers)
4. high maintenance, while warranty usually covers the unit itself, it does not cover spare parts that need to be replaced due to wear and tear. Check with the supplier before you buy your heaters, usually they include installation for free, after sales service and spare parts are of a different matter.
5. if there are a lot of water impurities, the pressure will drop every so often and the filter will need to be cleaned regularly. So ask your plumber where it is located so you can clean it yourself, otherwise, your water heater will not work properly.

Advantages of Storage Type Water Heaters

1. gives you the pleasure of equal hot & cold water flow
2. Some brands like Rheem automatically shut down when the water reaches 90 degrees and reheat if water temperature drops below default settings.
* some add a breaker to switch heater off upon leaving the house or when not in use to save cost & energy
3. generally low maintenance, you need only to replace thermostat after a few years as long as unit is protected against outside elements.
4. one unit can supply hot water to the house (it is sometimes advisable to put 2 units on different locations especially if some rooms are too far from the heater where hot water has to travel a certain distance)
5. not water and pressure sensitive
6. even if the heater is off or during power outages, pre-heated water is kept warm for hours because of the insulated tank.

Disadvantages of Storage Type Water Heaters
1. space consuming
2. heat loss occurs on still water trapped in pipes between faucet and heater therefore will take time to be replaced by hot water from heater (wastage of energy over long centralized pipe works)

3. pre heating required...from 15 minutes onwards depending on tank capacity

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