Instant vs Storage Geyser: Which One to Buy (3L, 5L, 10L, 15L or 25L)

Buy an instant geyser (3-6 litres) if you need hot water for a kitchen sink, washbasin or one quick bath at a time. Buy a storage geyser (10-25 litres) if two or more people bathe one after another in the morning, or if your bathroom wiring cannot take a 3 kW load. Instant models heat a small tank in about two minutes but run out fast. Storage models take 15-25 minutes to heat but give you enough hot water for several buckets.

This guide explains the trade-off with simple numbers, then matches each size to a household. Current verified prices for every model mentioned are on our live offers page.

What is the real difference?

In India, almost every "instant geyser" sold online is not tankless. It is a small tank of 3 to 6 litres with a powerful 3 kW element. A "storage geyser" is a larger insulated tank of 10 to 25 litres with a 2 kW element that heats more slowly and holds the heat.

	Instant geyser	Storage geyser
Tank size	3-6 L	10-25 L
Typical element	3,000 W	2,000 W
Current draw at 230 V	about 13 A	about 8.7 A
Time to heat a full tank (15°C to 45°C, ideal)	about 2-4 min	about 16 min (15 L) to 26 min (25 L)
Hot water per heating cycle	3-6 L	10-25 L
Best for	Kitchen, washbasin, one quick bath	Family bathroom, back-to-back baths
Wall space	Small	Larger, heavier when full

The heat-up times come from basic physics: heating 1 litre of water by 1°C takes about 4,186 joules. A 3 L tank at 3,000 W needs roughly 2 minutes for a 30°C rise. A 15 L tank at 2,000 W needs about 16 minutes. Real units take a little longer because of heat loss, but the ratio holds.

How much hot water does one bath need?

A bucket bath uses roughly 15-20 litres of water at around 40°C. You do not fill the bucket from the geyser alone. You mix hot water with cold tap water.

If your geyser stores water at 60°C and the tap gives 15°C, you need just over half the bucket from the geyser: about 10 litres of hot water per bucket. So:

• A 3 L instant geyser cannot fill a bucket in one go. It keeps reheating while you draw, so the water turns lukewarm partway through. It works for a short shower or a half-bucket, and it is ideal for a sink.
• A 5-6 L instant geyser gives a usable single bath if you are not in a hurry, especially in mild winters.
• A 10 L storage geyser covers about one full bucket bath per heating cycle.
• A 15 L storage geyser covers one to two baths back to back.
• A 25 L storage geyser covers two to three baths before it needs to reheat.

These are rough estimates. Colder tap water in north Indian winters means you draw more hot water per bucket.

Wiring: the question most buyers skip

A 3 kW instant geyser pulls about 13 amps. That needs a 16 A socket on a properly sized circuit, and the installer should check the wire gauge and the MCB rating. Plugging a 3 kW geyser into an old 6 A socket or a thin extension cord is a fire risk.

A 2 kW storage geyser pulls about 8.7 A. It also belongs on a 16 A socket, but it is gentler on older wiring.

If you live in an older flat or a rented home and are not sure about the wiring, the storage geyser is the safer default. Ask the installer to check before mounting either type.

Which one uses less electricity?

Neither is automatically cheaper. It depends on how you use it:

• Instant geysers waste less standby heat. The tank is small, so little stored water loses heat through the day. Switch it on, use it, switch it off, and it is efficient.
• Storage geysers lose some heat while sitting. A 5-star BEE rating means better insulation and lower standby loss. Switching it on 20 minutes before the bath and off afterwards cuts that loss further.
• The energy to heat a litre of water is the same. A 3 kW heater running 3 minutes and a 2 kW heater running 4.5 minutes use the same units. The difference is wasted standby heat, not the heater wattage.

Our geyser electricity bill guide works out the units per bath in detail.

Match the geyser to your home

Your situation	Pick	Size
Kitchen sink, dishes, washing hands	Instant	3 L
One person, short baths, small bathroom	Instant	5-6 L
One or two people, bucket baths	Storage	10-15 L
Family of three or four, one bathroom	Storage	15-25 L
Old wiring, rented flat	Storage	10-15 L
Hard water area	Either, with a glass-lined or SS tank and a magnesium anode	Any

On tank material, our glassline vs stainless steel tank guide explains which lasts longer in hard water. If you only bathe with one bucket a day and want the cheapest option, compare an immersion rod with a geyser first.

Current instant geyser deals

These are live deals on RichDeals. Each price was verified on the Amazon product page when the deal was posted. Prices change often, so confirm before you pay.

• Bajaj Aquaquick 3 L, 3 kW instant water heater at ₹2,999 (M.R.P. ₹5,720): rust-proof thermoplastic body and copper element. Rated 3.9 from 33 ratings. A good kitchen-sink pick.
• GM Fogo 5 L, 3 kW instant water heater at ₹2,799 (M.R.P. ₹6,390): 6.5 bar pressure rating and a magnesium anode.
• Milton 5 L, 3,000 W instant geyser at ₹3,749 (M.R.P. ₹8,999): SS304 stainless steel tank, thermostat and thermal cut-out. Rated 4.1 from 35 reviews.
• Orient Aura Rapid Pro 5.9 L instant water heater at ₹3,599 (M.R.P. ₹7,990): 3,000 W copper element.
• Crompton Arno Neo 5.9 L instant water heater at ₹3,999 (M.R.P. ₹7,999): 3 kW with a stainless steel tank.

Current storage geyser deals

• Longway 10 L storage geyser at ₹3,099 (M.R.P. ₹6,659): the budget pick for one person. Rated 3.8 from 25 ratings, so the review base is thin.
• Crompton Arno Plus 15 L 5-star storage geyser at ₹6,359 (M.R.P. ₹15,800): rated 3.9.
• Bajaj Armour Contempo 15 L 5-star storage geyser at ₹7,711 (M.R.P. ₹17,900): rust-proof tank and a 7-year tank warranty.
• Haier Aqualis 15 L 5-star storage geyser at ₹9,799 (M.R.P. ₹19,990): 2.2 kW element, 8 bar pressure rating, free installation with two connection pipes, 4-year product and 7-year tank warranty.
• RR Signature Zello 25 L storage geyser at ₹5,599 (M.R.P. ₹13,500): glass-lined tank, 8 bar. The cheapest 25 L option here.
• Havells Adonia Spin 25 L 5-star storage geyser at ₹11,598 (M.R.P. ₹21,790): 2,000 W, sized for a family bathroom.

For more water heaters and home appliances on sale today, browse all current offers.