Quick answers
The calculator's answer for the most common homes, for a vertical geyser. The same arithmetic, just pre-worked.
| Use | Mild winter | Cold winter |
|---|---|---|
| Kitchen sink | 6 L | 10 L |
| 1 bucket bath | 15 L | 25 L |
| 2 bucket baths in a row | 25 L | 35 L |
| 1 shower, 5 min | 25 L | 35 L |
| 1 shower, 10 min | 50 L | 70 L |
| 2 showers in a row, 5 min each | 35 L | 70 L |
| 3 showers in a row, 5 min each | 50 L | 100 L |
| 1 rain shower, 8 min | 50 L | 70 L |
| A bathtub | 50 L | 100 L |
Mild winter means Mumbai, the coast and the south; cold winter means north and central India, where tap water can fall to about 12 °C.
How the calculator works
It adds up the warm water your busiest spell needs, then finds the smallest standard tank that delivers it. A tank delivers more than its own size, because hot water at 60 °C is mixed with cold at the tap. It also delivers a little less than the full mix would suggest, because cold water flows in as hot flows out, so the last part of the tank comes out tepid. And the element keeps heating while water runs, which adds a few litres per minute.
In one line:
warm water = tank litres × usable share × (stored − tap) ÷ (use − tap) + what the element reheats while water runs
Worked through for one 5-minute shower in Mumbai: the shower needs 5 × 8 = 40 litres at 40 °C. A 25 litre tank gives 25 × 0.7 × (60 − 25) ÷ (40 − 25) ≈ 41 litres, plus about 10 litres reheated over the five minutes, which is enough. A 15 litre tank gives about 34, which is not.
The assumptions
| Assumption | Value |
|---|---|
| Water stored at | 60 °C |
| Shower or bath at | 40 °C |
| Bucket, washing-up at | 45 °C |
| Tap water, mild winter | 25 °C |
| Tap water, cold winter | 12 °C |
| Shower flow | 8 L/min |
| Rain shower flow | 12 L/min |
| Bucket bath | 20 L |
| Bathtub | 100 L |
| Gap between baths | 3 min |
| Usable share, vertical | 70% |
| Usable share, horizontal | 65% |
| Heating element | 2 kW to 50 L, 3 kW above |
Bucket water and washing-up are taken at 45 °C because they cool while you use them. The usable share is lower for a horizontal tank because hot and cold mix more in a short, wide tank. All the figures are deliberately on the cautious side: running out of hot water is the complaint we hear most about geysers, and it is never fixed by a bigger element, only by a bigger tank.
What each size costs
Lowest price for each storage size we stock, from our live catalogue:
| Size | Models | From |
|---|---|---|
| 6 litres | 8 | ₹7,000 |
| 10 litres | 9 | ₹7,600 |
| 15 litres | 12 | ₹8,129 |
| 25 litres | 12 | ₹9,350 |
| 35 litres | 4 | ₹11,550 |
| 50 litres | 4 | ₹12,650 |
| 70 litres | 4 | ₹17,300 |
| 100 litres | 4 | ₹19,650 |
| 140 litres | 2 | ₹37,129 |
| 200 litres | 2 | ₹46,059 |
For which model to pick at each size, see the best Jaquar geyser for 2026 and Jaquar vs Venus. For the reasoning behind the sizes, read the geyser capacity guide.