15 Litre vs 25 Litre Geyser: Which Capacity Suits Your Home?

Choose a 15 litre geyser if baths in your home are spread across the morning, and a 25 litre geyser if two or more people bathe back to back or your winter tap water is very cold. The price gap is small. In the Orient Electric range, moving from 15L to 25L adds Rs. 500 to Rs. 1,160 depending on the model. What it buys is a bigger store of hot water at the start, not a faster heater. This guide compares 10L, 15L and 25L with worked numbers so you can see what each gives you.

10L, 15L and 25L side by side

Worked example: the tank is set to 55 degrees C, you bathe at 40 degrees C, the element is 2000W and no heat is lost. Bath water is capacity x (55 minus tap temperature) divided by (40 minus tap temperature).

Back-to-back baths in winter

This is where the two sizes part ways. All three sizes heat at the same rate, because the element is the same. At a 10 degree tap, a 2000W element warms about 1 litre of water a minute to bath temperature, and at a 20 degree tap about 1.4 litres a minute. The tank only decides how many litres are waiting before the wait begins. The table assumes each bath takes about 20 litres of bath-temperature water.

For two baths in a row, a 25L geyser nearly removes the wait. For four baths in a row, even a 25L needs about 45 minutes of heating on a cold morning, so spacing out the baths still helps. For a family of four, 25L is a clear step up from 15L, and it works best when baths are spaced a little. Our blog on why a 25L geyser suits a family of four goes further into household routines.

What each step costs

The price step between sizes depends on the model. The table shows the live price of the same geyser at three sizes, and the price per litre of tank.

The 25L is always the better price per litre of tank, and the step from 15L to 25L is never more than Rs. 1,160. On the Enamour Classic Pro it is just Rs. 500. If you are choosing between 15L and 25L and you have the wall space, price is rarely the reason to stay small. The Maverick also comes in 10L and 25L, at Rs. 7,940 and Rs. 9,570. Compare every 15 litre geyser and 25 litre geyser in our model guides.

Running cost: does 25L use more electricity?

A 25L tank uses more energy to heat once, because there is more water in it. But it also gives you more hot water, so the energy per litre of bath water is nearly the same. At a 15 degree tap, a full 15L tank uses about 0.70 units and gives about 24 litres of bath water. A full 25L tank uses about 1.16 units and gives about 40 litres. That is about 0.029 units a litre for both. You pay for the hot water you use, not for the size of the tank.

The one place a bigger tank can cost a little more is heat that leaks out while it sits idle, since it has more surface. Good insulation and a moderate thermostat setting reduce this, and switching the geyser off when no one needs hot water helps most. Our guide to how geyser power consumption is calculated shows the working for your own tariff, and tips to reduce winter water heating costs show where the savings are. 3 star vs 5 star geysers explains how the star rating relates to idle heat loss.

Space and wall load

A full 25L tank carries 25 kg of water, which is 10 kg more than a 15L tank, and the 25L geyser is also bigger. Before you choose, measure the wall space, check the wall type and look at the pipe positions. Solid brick or concrete takes the load well, while a hollow or panelled wall does not, and a technician can check it. If the space or the wall is the limit, 15L is the practical choice. Browse 15 litre and 25 litre geysers to see every size, and read our geyser safety guide for earthing and fitting.

Which to pick

Our geyser capacity guide explains how to size a geyser for any household, and the 10 litre geysers are the place to start for smaller homes.

Frequently asked questions

Q: Is a 15 litre or 25 litre geyser better for 4 people?

A: If baths are spread across the morning, a 15L is enough. If two people bathe back to back, a 25L is the better choice. In our worked example, two baths in a row on a 10 degree tap leave you waiting about 18 minutes with a 15L tank and about 3 minutes with a 25L tank.

Q: Is a 10 litre geyser enough for 2 people?

A: Yes, if they bathe at different times. A full 10L tank gives about 15 litres of bath water at a 10 degree tap, which is a little under one bucket bath. A second bath within the hour means about 26 minutes of heating. If you bathe together, choose 15L.

Q: Does a 25 litre geyser take longer to heat?

A: Yes, to heat a full tank. At 2000W, a 25L tank takes about 35 minutes from 15 degrees C to 55 degrees C, and a 15L tank takes about 21 minutes. But the 25L gives you more hot water to start with, so for a single bath you rarely wait for it. Switch it on a little earlier on winter mornings.

Q: Does a 25 litre geyser cost more to run?

A: It costs more to heat a full tank, about Rs. 9.30 against about Rs. 5.60 for 15L at Rs. 8 a unit, but it also gives about 40 litres of bath water against about 24. The cost per litre of bath water is nearly the same.

Q: Is a 15 litre geyser enough in winter?

A: For two or three people with baths spread out, yes. When the tap water drops towards 10 degrees C, a full 15L tank gives about 22 litres of bath water, which is about one bath. If more than one person bathes in a row, 25L is more comfortable.

Q: Can I upgrade from 15L to 25L later?

A: Yes, but check the wall first, since the 25L is heavier and bigger, and the pipe positions may differ. It is simpler to decide before you buy. If your old geyser is failing, see the signs it is time to replace it to pick the right time.

Browse all storage geysers or the vertical geysers range. Our geyser buying guide and storage geyser buying guide walk you through the rest.