How much your geyser really adds to the bill

A geyser is the single largest electrical load in most Indian homes. It is also the one people worry about most and understand least — including the widespread belief that switching it off between baths saves money.

The arithmetic, once

Heating water takes a fixed, knowable amount of energy. Raising 25 litres by 40 °C — cold tap to comfortable bathing temperature — takes roughly 1.16 units of electricity.

At ₹7.50 a unit, that is about ₹8.70 for a full tank. Heat two tanks a day for a month and you are at roughly ₹520, plus a little for standing loss.

Should you switch it off between baths?

Usually no, and this surprises people.

A geyser only consumes power when the element is on. Once the water is at temperature, the thermostat switches off and the unit draws nothing. It comes back on briefly to top up the heat lost through the insulation — that loss is called standing loss, and on a well-insulated tank it is small.

Switching off completely means the water cools all the way down, and next time you need it you pay to heat the whole tank from cold again. Leaving it on means paying only for the standing loss. Over a day, leaving it on generally costs less, and it certainly costs less waiting.

The exception is genuine long absence. Going away for a week? Switch it off — there is no point maintaining temperature for nobody.

Why insulation is the thing to care about

Standing loss is decided entirely by insulation quality, and it is the easiest thing for a manufacturer to cheapen because a customer cannot check it in a shop.

A poorly insulated tank loses so much overnight that you are effectively reheating from cold every morning. That is not a small difference — it is potentially double the running cost, every day, for the life of the unit. High-density PUF foam is what you want, and it is worth asking about.

Three habits that genuinely reduce consumption

1. Do not run the thermostat at maximum

Setting it to the highest position does not heat water faster. It heats the same water to a higher temperature, which you then dilute with cold at the tap. You have paid to heat water you did not need heated. Around 55–60 °C is plenty, and it deposits scale more slowly too.

2. Heat once, use in sequence

Four people bathing across two hours means the geyser reheats several times. The same four bathing within 40 minutes means one heating cycle and a top-up. Same water, noticeably less electricity.

3. Descale on schedule

A scaled element takes longer to heat the same water, which means more units for the same result. In hard-water areas this is quietly one of the biggest contributors to a rising bill, and people almost never connect the two.

What does not help

• A stabiliser. It does not reduce consumption. Our water heaters do not require one.
• Switching off at the switchboard rather than the unit. Identical outcome, and you will forget.
• Buying a smaller tank to save power. Energy depends on how much water you heat, not how big the tank is. Too small just means reheating more often.

Working out your own number

Every product page on this site has a calculator: enter your capacity, how many tanks a day you heat and your actual tariff, and it estimates the monthly cost. Using your own tariff matters — rates vary widely by state and slab.