Solar water heater vs electric geyser: the Kerala arithmetic

Before rooftop PV became the star, solar water heating was the original rooftop solar in Kerala, and it is still one of the fastest-payback purchases a household can make. We have supplied and installed them alongside power plants since 2009.

What a geyser really costs

A 2 kW electric geyser running an hour a day consumes around 60 units a month. At domestic tariffs that is real money every month, forever, and it lands in the higher slabs of your bill where units cost the most. A solar water heater removes most of that load permanently.

Sizing and what to check

For a family of four, a 200 LPD (litres per day) system is the usual fit; smaller homes manage with 100 to 150 LPD. Check the tank's inner material and insulation, and make sure the installer includes a backup heating element for the darkest monsoon weeks, when water arrives warm rather than hot.

A quality system lasts well beyond fifteen years, which is several electric geysers' worth of lifetime. Combined with rooftop PV, the arithmetic gets even simpler: heat the water directly from the sun, and let your panels cover what remains.