Updated October 2026.
Somebody comes up to our counter most weeks having read about tankless water heaters online. They've seen the American reviews, the "hot water forever" line and a figure saying tankless saves a quarter of your bill, and they want a tankless geyser for the bathroom. Then they look along our wall of geysers and ask, quite reasonably, which one of these is it.
It's a fair question. So here's the conversation we have across the counter, with the physics and the published figures behind it. What tankless really means, why almost nothing on an Indian shop wall is tankless at all, where the big savings figures come from, and what actually decides how much electricity your geyser uses. We'll also correct a few things the earlier version of this page got wrong.
Is a tankless geyser more energy efficient than a tank geyser?
Yes on paper, because a tankless geyser doesn't spend power keeping stored water hot, but in an Indian home the saving is smaller than the famous figures suggest and the geyser you'll actually use is still a tank. Both kinds turn electricity into heat in the water. The difference is what happens between showers. A tank sits there losing a little heat through its walls all day, and the element tops it up. A tankless unit has nothing stored to lose.
People ask us which one is more efficient when what they mean is which one gives them a lower bill. Those two questions have different answers here, because the efficient design comes with a power demand most flats can't supply. The choice nearly always comes down to a storage geyser with a good star rating, sized and switched sensibly.
Is an instant geyser the same as a tankless geyser?
No, an instant geyser is a small storage geyser with a powerful element, usually holding 1 to 6 litres. This is the single biggest mix-up in this aisle, and the old version of this page made it too.
Look at the paperwork. Racold's manual for its Pronto instant range lists 1, 3 and 5 litre capacities, a 3 kW or 4.5 kW element, and a pressure rating for the tank. The quick start steps tell you to fill the heater completely before switching it on, and the maintenance section asks you to check the anode within six months (Racold Pronto manual). You only fill and protect a tank. AO Smith describes its MiniBot instant geyser as having a glass lined tank with a wall thickness of 2 mm (AO Smith MiniBot 3kW).
So an instant geyser keeps a few litres hot, gives you those quickly, and then warms the water passing through as best its element can. It isn't a tankless geyser, and it doesn't escape standby loss. It just has less water to lose heat from.
A true electric tankless geyser does exist in India. AO Smith sells one, the ZIP, which it calls a digital tankless water heater with a 5,500 watt element and a 6 bar pressure rating (AO Smith ZIP). That 5,500 figure is the important part, and it's why you see so few of them.
Why don't most Indian homes use an electric tankless geyser for a shower?
Because heating a full shower as it flows takes far more power than a normal home circuit is built to deliver. It's simple arithmetic, and it settles the question.
Water needs about 4.18 kilojoules to warm one kilogram by one degree (Engineering ToolBox). A water saving showerhead certified under the US WaterSense scheme flows at no more than 2.0 gallons a minute, about 7.6 litres, and a standard one at 2.5 gallons, about 9.5 litres (US EPA WaterSense). Say your cold water comes in at 15°C and you want 40°C at the shower. Warming 7.6 litres a minute by 25 degrees, on the spot, needs about 13.2 kW. At 230 volts that's over 57 amps.
Now compare what's on the wall. A 3 kW instant geyser can lift that same shower by under 6 degrees once its stored litres run out. The 5,500 watt tankless unit lifts it by about 10 degrees. Turn the flow down to 3 litres a minute and the 5,500 watt unit manages about 26 degrees, which is a comfortable but gentle shower.
That's where the instant geyser fits. A 3 kW element is about as much as a single 16 amp power point is comfortable with. Racold's instant manual asks for a supply rated at 15 amps minimum for its 3 kW models and 20 amps for 4.5 kW. Rather than demand a supply your flat doesn't have, it stores a few litres to cover the gap. A bigger tankless unit needs its own heavy circuit, and we'd want your electrician to check the wiring and your sanctioned load before you buy one.
Where does the "tankless saves 25 to 34%" figure come from?
From American gas water heaters, not Indian electric geysers. The earlier version of this page told you a tankless geyser cuts energy costs by 25%. We've corrected that, because the research behind numbers like that measures something else, and we'd rather fix it than leave it standing.
The clearest primary source is a US Department of Energy Building America study. It compared a gas storage heater with a gas tankless heater in a real home. A typical tankless heater with an energy factor of 0.8 suggests about a 33% cut in gas use against a typical 0.6 storage heater, but actual savings vary a lot with the size of each draw. They're smaller for short draws, because the heat exchanger loses heat every time it cools down after use, and the greatest savings came at about 50 gallons a day (US Department of Energy, Building America).
Here's why that doesn't carry across. A gas storage heater wastes heat up its flue and through its tank all day, so there's a lot of waste to cut. An electric element in a well insulated tank has only one real loss, the heat leaking through the walls between uses. Take that away and you save that leak, nothing more. With an electric geyser, how much hot water you use matters far more than which type you buy.
How much electricity does a tank geyser waste keeping water hot?
Less than most people fear on a five star geyser, and that loss is exactly what the BEE star label measures. BEE rates storage geysers on standing loss, the energy a full tank uses over 24 hours just holding its water 45°C above the room, with no water drawn (BEE star rating plan, via NZEB). That's the very loss a tankless unit avoids, so the star label is a direct read on the gap between them.
| Tank size | Five star ceiling, units a day | One star ceiling, units a day |
|---|---|---|
| 6 litres | 0.396 | 0.792 |
| 25 litres | 0.693 | 1.386 |
| 50 litres | 0.916 | 1.832 |
| 100 litres | 1.188 | 2.376 |
Ceilings from the BEE standing loss table, tested at a 45°C difference. Your real loss depends on the thermostat setting, the room and how long the geyser stays switched on.
Read it like this. A five star 25 litre geyser left on round the clock is allowed to lose up to about 0.69 units a day keeping itself hot. A one star tank of the same size can lose twice that. The gap between a good tank and a poor tank is as big as the gap between a good tank and a tankless unit, and it costs you nothing extra to close at the counter. You'll find your slab rate on the BSES Delhi tariff schedule.
Which is cheaper to run, a storage geyser or an instant geyser?
The one sized for the job, which usually means instant for the kitchen and storage for the bathroom. Both are tanks. The small one wins where you want a few litres often, the big one wins where you want a bucket or a shower at once.
Over a kitchen sink you might run hot water ten times a day for a minute at a time. Keeping 25 litres hot for that is wasteful. A 3 or 5 litre instant geyser holds just enough, heats it fast, and has a much smaller surface to lose heat from. In a bathroom it's the other way round. A small instant geyser runs out of stored water partway through a shower, and the element on its own can't keep up, as the chart shows. A storage tank sized for your family heats once and delivers.
The cheapest habit with either kind is the switch. Turn the geyser on a while before you need it, and off when the last person's done. We cover how this changes when the weather turns in our guide to running a geyser in winter.
Do tankless geysers really last 20 to 30 years?
That figure belongs to American gas tankless heaters, and even there the maker we checked says about 20 years, not 30. The old version of this page said a tankless geyser lasts 20 to 30 years and a tank only 10 to 15. AO Smith's American site puts gas tankless heaters at about 20 years, roughly double a standard tank (A. O. Smith US). That describes a different machine on a different fuel, so we've taken the claim out rather than repeat it.
For the geysers you'll actually buy here, the better guide is the warranty and the maintenance. Racold gives seven years on the inner tank of its CDR storage range and five years on the tank of its Pronto Neo instant geyser. Its manuals for both ask for the anode, the sacrificial rod that protects the tank, to be checked within six months and replaced once it's worn below 7 mm. The storage manual makes the annual anode check a condition of the tank warranty (Racold CDR manual).
The earlier page also said tank geysers only need flushing twice a year while tankless ones need regular professional service. Neither is right as a rule. Both types here are tanks, and both want the same thing, an anode check and a flush. In our experience it's hard water, more than the design, that shortens a geyser's life in Delhi NCR. If your water's salty enough to scale the element quickly, it's probably the same water that makes some homes need an RO water purifier in the kitchen, and it's worth getting it tested once.
What about a gas tankless geyser?
Gas is the usual way to get true tankless hot water at full shower flow, but it has to be fitted with proper ventilation, and we don't sell gas geysers. A gas burner can put out far more heat than a household socket can.
The risk is the flue gas. Doctors in Ludhiana described young people collapsing while bathing in closed bathrooms with LPG geysers, with carbon monoxide the suspected cause (Annals of Indian Academy of Neurology). If you already have a gas tankless heater in a bathroom without a working vent, that's the first appliance we'd change.
Which geysers do we suggest at the counter?
An instant geyser for the kitchen and a five star storage geyser for the bathroom, and here are the four we reach for. The specs below are the makers' own.
Racold Pronto Neo 5 L Instant Water Heater
The one we fit over a kitchen sink when the family cooks a lot, under Rs 5,000. Racold lists a 3 kW element, a 6.5 bar pressure rating, three layers of safety with a thermostat, cut-out and safety valve, PUF insulation for heat retention, and a five year tank warranty. It's the closest thing to tankless convenience you can plug into a normal socket, and now you know why that's a small tank and not a tankless geyser.
AO Smith MiniBot 3 L Instant Water Heater
The one for a tight spot, also under Rs 5,000. AO Smith publishes a 3,000 watt glass coated element, a Blue Diamond glass lined tank with 2 mm walls, and an 8 bar pressure rating for high rise buildings. It's the pick when somebody wants hot water at a powder room basin or a small kitchen and there's very little wall to spare.
Racold CDR DLX Plus 35 L Storage Geyser
The one we suggest when someone's come in for efficiency and has a family to bathe, at around Rs 10,000. Racold rates the CDR DLX range five star, with a Titanium Plus enamelled tank, a magnesium anode, a rust proof body, three layers of safety and a seven year inner tank warranty. The Plus adds a temperature knob and a temperature indicator. If you came here looking for the lowest running cost in a bathroom, this is what that looks like in practice.
Racold Platinum NXT 50 L Storage Geyser
For a bigger household or a bathroom with a large shower, in the mid Rs teens. Racold lists high density PUF insulation for longer heat retention, a temperature display with a knob, a Children Care mode against scalding, a magnesium anode, a Titanium Plus tank and a seven year inner tank warranty. It's the one we point to when several people bathe back to back in the morning.
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 see them on the wall. Our full range, instant and storage, is in the geyser collection.
Our advice before you spend, and it costs us nothing to give it. Don't chase the tankless label. Decide where the hot water's needed, kitchen or bathroom, and how many people use it at once. Pick an instant geyser for the first and a five star storage geyser for the second, and switch it off when you're done. Do those three things and you'll get most of what a tankless geyser promises, on the wiring you already have.