Updated October 2026.
Every year, on the first properly cold morning in Delhi, our phone starts ringing about geysers that have "stopped working". The same geyser that gave a hot bath all through the warm months is suddenly slow, the water runs lukewarm halfway through, and somebody in the family is sure it's broken. Most of the time it isn't. It's doing exactly what it did in summer, with a much harder job to do.
So here's the conversation we have across the counter every winter, written down. Why a geyser in winter behaves differently, what to set it to, what it adds to the bill, whether it can share a circuit with a room heater, and the geysers we'd put in your bathroom.
Why does my geyser take longer to heat water in winter?
Because the water coming into it is much colder, so the same heating element has far more work to do before the water's hot. A slow geyser in winter usually isn't a faulty one. It's being asked to lift the water through more degrees than it was in summer.
It takes about 1.16 watt hours to warm one litre of water by one degree, a figure that falls straight out of water's specific heat (Engineering ToolBox). That's all you need to see why winter feels so different. Here's the sum for the two most common bathroom sizes, heating to 60°C with a standard 2,000 W element. We've used round numbers for the incoming water to show the gap, so treat them as an illustration rather than a reading from your tap.
| Tank | Energy, water in at 30°C | Time at 2,000 W | Energy, water in at 15°C | Time at 2,000 W |
|---|---|---|---|---|
| 15 litres | about 0.52 units | about 16 minutes | about 0.79 units | about 24 minutes |
| 25 litres | about 0.87 units | about 26 minutes | about 1.31 units | about 39 minutes |
That's the best case, with no heat lost through the tank wall, so the real time is a little longer. But look at the jump. Half as much again, just because the water came in colder.
That's the reason we ask people to switch on a little earlier in winter rather than book a service visit. If the geyser was fine in October and it's slow in January, the water's changed, not the geyser. If the heating light never goes off, or it trips the switch, that's worth a call.
What temperature should you set your geyser to in winter?
Keep the stored water at about 60°C and mix it down at the tap, rather than turning the geyser down to bath temperature. That's the setting public health bodies use for hot water tanks, and for a geyser in winter it matters as much as in summer.
The bacteria behind Legionnaires' disease grow in water between 20 and 50°C, best at around 35°C. The WHO's guidance for hot water systems is to keep the water above 50°C, which means water leaving the heater should be at 60°C or more (WHO, Legionellosis). The UK's Health and Safety Executive puts it the same way: store hot water at 60°C at least (HSE). A tank set to a lukewarm 40°C is sitting right inside the range those bacteria like. We'd rather you heard that from us than from nobody.
The flip side is scalding. Water at 60°C straight onto a child's skin or an elderly parent's is a real risk, and it's the reason some people turned the knob down in the first place. The answer is to mix, not to lower the tank. Open the cold tap first, then bring in the hot. If there's a small child in the house, a geyser with a child safety mode or a clear temperature display takes the guesswork out, and we've put one of those in the picks below.
Most people never touch the knob, and on a lot of geysers the manufacturer would rather you didn't. Racold's manual for its CDR range says the thermostat is set at the factory and recommends not changing it (Racold CDR manual). If yours has a knob or a display, use it. If it doesn't, leave it alone and use the mixer.
Does a geyser use more electricity in winter?
Yes, and usually a lot more, for three reasons that stack on top of each other. Every litre needs more energy, people use more hot litres, and a tank sitting in a cold bathroom loses its heat faster.
The first we've already shown. Water in at 15°C instead of 30°C needs half as much energy again to reach 60°C. The second is behaviour. In summer half the family showers cold. In winter everybody wants hot water, for longer, and the mix at the tap leans further towards the hot side because the cold side is so cold. The third is the tank itself. BEE's star rating for storage geysers is measured on standing loss, the energy a full tank uses in 24 hours just keeping its water warm, tested at 45°C above the room (BEE star rating plan, via NZEB). A colder bathroom widens that gap, so the tank leaks a little more heat than it would in summer.
That's why the geyser in winter is so often behind a bill that jumps, while the room heater takes all the blame.
How many units does a geyser use in a month in winter?
Roughly 24 units a month for every 15 litres of hot water you draw a day in winter, against about 16 in summer, before the tank's own standing loss. The chart below runs the same sum for bigger families.
The sum's easy to redo for your own house. Litres of hot water a day, times the degrees you're raising it, times 1.16, gives watt hours. Divide by 1,000 for units, then times 30. A unit is one kilowatt hour, the same unit on your bill.
Then add the standing loss. Under BEE's star plan, a 15 litre tank earns five stars only if it loses no more than 0.569 units in 24 hours, while a one star 15 litre tank can lose up to 1.138. For 25 litres the five star ceiling is 0.693 units a day and one star goes up to 1.386 (BEE star rating plan, via NZEB). Over a month that's up to about 21 units for a five star 25 litre geyser left on round the clock, against up to about 42 for a one star tank of the same size. Your slab rate is on the BSES Delhi tariff schedule, and remember that extra units can push the whole bill into a dearer slab.
So the star rating matters most for what it costs to keep water hot while nobody's using it. If you heat it, use it and switch off, the stars matter less than the habit.
Is it OK to keep the geyser on all day in winter?
It's safe on a sound, properly fitted geyser, but it isn't free, and on an old tank it's the most expensive habit in the bathroom. The thermostat stops the element running nonstop, so all day costs you the standing loss, not the full wattage.
On a five star tank that's the half unit to seven tenths of a unit a day we've just shown. On a tired one star tank it can be twice that. The habit we suggest is the simple one. Switch it on before the first bath of the morning, wait for the heating light to go off, and switch it off once the family's done. With a geyser in winter that wait is longer, as the table at the top shows.
People also ask us whether to switch the geyser off while they're in the shower. A modern ISI marked geyser, properly earthed, with its safety valve and cut-out working, is designed to stay on. Our honest advice is still to switch it off once the light shows the water's hot. It costs you nothing, and in an older flat where nobody's sure about the earthing, it takes the doubt away.
One winter specific thing from Racold's manual that we pass on to anyone who's been away. If a water heater hasn't been used for 15 days or more, the water inside can smell for a while (Racold CDR manual). Back from a winter wedding trip? Run the hot tap through before anyone bathes.
Can I run a geyser and a room heater at the same time?
Yes, but not off the same socket circuit, because together they can draw more current than a single 16 amp point is meant to carry. Of everything people ask about a geyser in winter, this is the one that matters for safety.
A 2,000 W geyser draws about 8.7 amps at 230 volts. A 2,900 W oil-filled radiator draws about 12.6 amps. Together that's over 21 amps. A 3,000 W instant geyser on its own draws about 13 amps, and Racold's instant geyser manual asks for a supply of at least 15 amps for its 3 kW models (Racold Pronto manual). Racold's storage geyser manual says to use a 16 amp plug and make sure the three pin point is properly earthed (Racold CDR manual).
What we see go wrong is the extension board. The bedroom heater goes into a multi plug that shares a circuit with the bathroom, and the trip switch goes every morning at bath time. Each appliance on its own 16 amp point, never on an extension board, and the problem disappears. If the switch keeps tripping even then, get an electrician to look at the board before winter, not during it.
As for which heater to pair with your geyser, we've covered that properly in our guide to the best room heater for home, with running costs for each type and the five we'd recommend room by room. The short version is an oil-filled radiator for a room you'll sit or sleep in, and never any portable heater inside a wet bathroom.
Instant or storage: which geyser works better in winter?
A storage geyser for the bathroom, and an instant geyser for the kitchen sink. Running a geyser in winter is where the difference shows most.
An instant geyser has a small tank, usually 1 to 5 litres, and a powerful element. It gives you its small tank of hot water quickly and then heats the water as it flows. At 3,000 W and 3 litres a minute, which is the flow rate Racold's manuals quote for best hot water performance, the element can lift the water by about 14 degrees as it passes through. In summer, with water coming in warm, that's a comfortable shower. On a cold morning, with water coming in at 15°C, it's lukewarm once the stored litres run out. We've had plenty of customers bring an instant geyser back to the counter in January for exactly that reason, and it wasn't faulty. It was the wrong geyser for a winter bath.
In a kitchen, where you want a few litres of hot water to wash a pan, an instant geyser is ideal. In a bathroom where someone wants a full bucket or a proper shower, a storage tank of 15 litres or more is the one that keeps up.
Is a gas geyser safe in a bathroom in winter?
Only if it's installed outside the bathroom or the room is properly ventilated, and winter is when people close the ventilation. An electric geyser burns nothing and carries none of this risk.
A neurology team at Dayanand Medical College in Ludhiana described 14 young people who collapsed while bathing with LPG gas geysers in poorly ventilated bathrooms. The cases clustered in the winter months, and in one the small ventilator had been shut because of the cold (Annals of Indian Academy of Neurology). The suspected cause was carbon monoxide and other gases from incomplete burning of the LPG.
If you've got a gas geyser in a closed bathroom, especially one used by a teenager who takes long showers, that's the appliance we'd change first. It's not a sales line. We'd say the same if you bought the replacement somewhere else.
What should you check on your geyser before winter starts?
The safety valve, the scale, the plug and point, and the ISI mark, in that order. Ten minutes of checking saves the morning nobody has hot water.
- The safety valve. Racold's manual asks owners to move the safety valve lever up and down a few times every six months so lime doesn't build up in it (Racold CDR manual). The valve is what lets pressure out if the thermostat ever fails, so it's worth keeping free.
- Scale. The same manual recommends descaling the pipes, element and valve at least once every six months. If your water's hard, scale builds up on the element, and a scaled element takes longer to heat, which people then put down to the cold.
- Plug and point. A 16 amp plug, a three pin point with a working earth, and no extension board in between.
- Water first. If the geyser's been drained or shut off at the valve, open the hot tap and let water run through before you switch on. Heating an empty tank damages the element and isn't covered by warranty.
- The ISI mark. Storage electric water heaters in India are certified to IS 2082 (BIS product manual for IS 2082). If you're buying a replacement, look for the ISI mark on the unit itself.
We should also put right two things the earlier version of this page got wrong. It called the Bajaj Majesty an oil-filled water heater, when it's a room heater. And it said a geyser's polyurethane insulation protects you from electric shock. It doesn't. The insulation keeps the heat in. Shock protection comes from the earthing, the thermostat and the cut-out. We'd rather correct it out loud than leave it standing.
Which geysers do we recommend for winter?
If you're replacing a geyser in winter, one of these five, depending on the bathroom, the family and whether there's a small child in the house. Every spec below comes from the manufacturer's own published sheet or manual.
AO Smith Elegance Prime 15 L
The one we hand to a couple or a small family who want a geyser they won't think about again, at around Rs 8,000. AO Smith publishes a 2,000 W Incoloy element, a Blue Diamond glass lined tank, an 8 bar pressure rating that suits high rise flats, a five star BEE rating and a seven year tank warranty. The earlier version of this page recommended it too, and we still would.
Racold CDR DLX Plus 25 L
The family size pick, at under Rs 10,000, and the one we suggest when a household of four shares one bathroom in winter. It's the updated version of the Racold the earlier page listed. Racold lists a Titanium Plus enamelled tank, a magnesium anode, three layers of safety with thermostat, cut-out and safety valve, a rating for high rise buildings and a seven year tank warranty. The Plus version adds a temperature knob and a temperature indicator, according to Racold's manual, so you can see what the tank's holding. If you're two people, the 15 litre version is the same geyser in a smaller tank.
Racold Omnis Slim 15 L Horizontal
The one we suggest when the words small child come up, just under Rs 10,000. Racold publishes a temperature display with a control knob, a Children Care mode meant to protect against skin burns, a shower ready light, three layers of safety, a seven year tank warranty and a four year element warranty. The horizontal body fits a low loft or the space over a door where a vertical tank won't go, which is a problem we solve at the counter more often than you'd think.
Racold CDR DLX Plus 15 L
The second bathroom pick, at around Rs 8,000. Same Titanium Plus tank, three layer safety, knob and indicator as the 25 litre above, in a size that's enough for one or two people. It's the sensible answer for a guest bathroom that sits empty most of the year and needs to be ready when family visits in winter.
Racold Pronto Neo 3 L Instant
For the kitchen, under Rs 5,000. Racold's Pronto manual lists 3 kW for the 3 litre model, a 6.5 bar pressure rating, a thermostat and a non self resetting thermal cut-out, and Racold's product page gives a five year tank warranty. It's the geyser we fit over a kitchen sink so nobody's washing oily pans in cold water through January. We'll steer you away from it for a bathroom, for the reason we gave above.
Where can I buy a geyser online in Delhi NCR?
You can buy any of these online from us and have it delivered across Delhi NCR, or come in and we'll talk it through with you. The full range sits in our geyser collection, storage and instant both.
Our advice before you spend anything, and it costs us nothing to give it. Count the people who bathe in that bathroom on a winter morning, check whether the point behind the geyser is a 16 amp socket, and measure the space, height and width, where it's going to hang. Bring those three things and we can tell you in two minutes whether you need 15 litres or 25, vertical or horizontal. Quite often we tell people their old geyser is fine and just needs descaling.
And if your geyser in winter is simply slower than it was in summer, give it a few extra minutes before you call anyone. That's the cold water, not a fault. A geyser in winter that never switches its heating light off, trips the switch or drips from the valve is the one to get looked at.