Instant geyser vs storage geyser
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Quick answer
Choose a storage geyser (10 to 25 litres) for a bathroom where two or more people bathe one after another, or where you want a bucket of hot water without waiting. Choose an instant geyser (1 to 5 litres) for a kitchen sink, a small bathroom used by one or two people, or a rental where you want something compact. Electricity use for the same amount of hot water is similar: it is set by physics, not by the type. What differs is the standby loss of a tank, the 3 kW or more load of an instant unit, and how each handles hard water.
Who this is for
Anyone in India choosing a water heater for the winter, whether for a flat or an independent house, and unsure between a tank (storage) and a tankless-style (instant) geyser.
Instant geyser vs storage geyser at a glance
| Instant geyser | Storage geyser | |
|---|---|---|
| Sizes on maker pages | 1 L, 3 L, 5 L and 6 L (Crompton, Racold, Bajaj, AO Smith) | 6 L, 10 L, 15 L and 25 L (Crompton, Bajaj); Racold goes up to 70 L |
| Heating element | 3 kW is common; 4.5 kW and larger exist | 2 kW is common (Crompton Arno Neo); a 3 kW turbo version also exists |
| Hot water supply | Small tank, heats in minutes; runs out after a few litres of a long shower | Large hot tank, so back-to-back baths work |
| Wait before use | Short | Switch on 15 to 30 minutes earlier |
| Standby heat loss | Very little | Some, reduced by foam insulation |
| Pressure rating on maker pages | 6 to 6.5 bar (Crompton, Bajaj) | 8 bar (Bajaj Crest Plus); Havells Monza Pro 0.8 MPa; Racold CDR DLX suited to high-rise |
| BEE star rating on maker pages | We did not find one on the instant pages we opened | Listed as 5 star on Crompton, Bajaj and Racold storage pages |
| Best place | Kitchen, small bathroom, rental | Main bathroom of a family home |
Which uses less electricity? Running cost in rupees per unit
Heating water takes the same energy however it is done. Water needs about 4.186 kJ per litre for every degree of temperature rise, and one unit (1 kWh) is 3,600 kJ. So raising 20 litres by 25 degrees C takes roughly 0.58 units. At an example tariff of around ₹8 a unit (use your own bill), that bucket costs around ₹5 in electricity. This is our own arithmetic and ignores losses.
The type matters in two ways. A tank loses some heat while it waits for you, so leaving a storage geyser on all day wastes units; switch it off after use. An instant geyser has almost no standby loss but draws a big load for a short time, which can trip a weak circuit.
- Our AC electricity cost calculator uses the same units-per-hour method if you want to cost an appliance against your own tariff.
- A 4.5 kW instant geyser needs a heavy-duty point. Ask an electrician to check the wire and MCB before buying; the maker’s manual states the requirements.
| Item | Result |
|---|---|
| Energy per 20 L bucket | About 0.58 units |
| Per month, 2 people | About 35 units, plus standby loss for a tank |
| Time to heat 20 L on a 3 kW instant unit | About 12 minutes of heating at full power |
| Time to heat a full 25 L tank by 40 degrees C on a 2 kW element | About 35 minutes |
| Current drawn at 230 V | 2 kW about 8.7 A; 3 kW about 13 A; 4.5 kW about 19.6 A |
Geyser for hard water: which type lasts longer?
Hard water leaves scale on the heating element and speeds up corrosion of the tank. Neither type is immune. What helps is the tank lining, the anode and the warranty.
- Racold: the Altro i DN instant geyser is described as “Duronox for hard water”, with a specially treated stainless steel tank. Its CDR DLX storage geyser uses a titanium enamel coating that Racold says handles even the toughest water conditions.
- Bajaj: the Shield series Crest Plus storage geyser has a marine-grade glass-lined tank with a 7-year tank warranty.
- AO Smith: says its Urbane series, with a Blue Diamond glass-lined tank, is designed to perform even in the toughest water conditions.
- Crompton: storage models carry a sacrificial magnesium anode rod with a stainless steel core to protect the tank; the Arno Neo page lists a 5-year tank warranty.
- Havells: the Monza Pro lists an Endurashield coated container and a protective anode rod.
Geyser for an apartment or an independent house
- High-rise flat: water pressure from a booster or a tall building can be high. Look at the working pressure on the maker page: 6 to 6.5 bar on the Crompton and Bajaj instant pages, 8 bar on Bajaj’s Crest Plus. Racold and Havells call their tanks suited to high-rise buildings.
- Independent house with a roof tank: pressure is low. Check the minimum pressure in the manual; the instant types need a steady flow to switch the element on.
- Limited wall space: storage geysers come in vertical and horizontal mounting (Havells and Racold list both), which helps under a loft or a false ceiling. Instant units are small and wall-mounted.
- Rented home: an instant geyser is easier to carry and fit. A big storage tank is worth fixing only if you will stay.
Geyser for bathroom or kitchen
For a kitchen sink, a 1 litre or 3 litre instant geyser is the usual choice: Crompton and Racold list 1 litre models, and Racold’s geyser finder asks whether the use is kitchen, bucket, shower, rain shower or bathtub. For a bathroom, the question is how many people bathe back to back. Racold’s finder asks that too, along with how cold your area gets.
3 L, 10 L, 15 L or 25 L: which size?
| Size | Suits |
|---|---|
| 1 L to 3 L instant | Kitchen sink, hand washing, a quick wash in a small bathroom |
| 5 L to 6 L instant | A bathroom for one or two people who bathe one after another with a bucket |
| 10 L storage | One or two people, a mild winter |
| 15 L storage | A family of three or four, one bathroom |
| 25 L storage | Four or more people, rain shower, or very cold weather |
BEE star rating on a geyser
The maker pages we read describe the Crompton Arno Neo and Bajaj Crest Plus storage geysers as 5 star rated, and Racold calls the CDR DLX a 5-star rated solution. A higher star means the tank loses less heat while it holds hot water, so the label is about standby efficiency and not about how fast it heats. We did not find a star rating on the instant geyser pages we opened. Our 3 star vs 5 star AC explainer covers how BEE stars work for air conditioners.
Which should you buy
- Family of three or more, one bathroom: a 15 L or 25 L storage geyser with a glass-lined or titanium-coated tank.
- Hard water at home: pick a tank with a stated hard-water lining and a long tank warranty, whatever the type.
- Kitchen, rental or single user: a 3 L instant geyser, after checking your wiring.
- Not sure: storage geysers are more forgiving for a growing family; instant ones are easier on space.
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Frequently asked questions
Which is better, instant or storage geyser?
Storage suits families who bathe one after another; instant suits kitchens, small bathrooms and rentals. Electricity use for the same hot water is similar, so pick by usage and space.
Which geyser consumes less electricity?
Heating the same water needs the same energy. A tank adds standby loss if left on; an instant unit has a high load for a short time. Switching a tank off after use keeps its running cost close.
Is an instant geyser safe?
Makers list safety valves, thermal cut-outs and shock protection on both types (for example Racold’s three layers of safety). Use a proper earthed point and an electrician-checked circuit.
Which geyser is best for hard water?
Look for a stated hard-water tank: Racold’s Duronox or Titanium Plus, Bajaj’s glass-lined tank, AO Smith’s Blue Diamond glass lining. Flush scale from the element on schedule.
How many litres do I need for a family of four?
As a rough guide, 15 L to 25 L storage for one bathroom. Racold’s geyser finder asks the number of back-to-back baths and your local temperature.
Sources
Checked on . Rules can change, so confirm with the official page before you travel or buy.
- Crompton: Rapidjet 5-litre 3000W instant water heater (specifications)
- Crompton: Arno Neo storage water heater (sizes, 2000W, warranty)
- Racold: Altro i DN instant geyser (hard water)
- Racold: CDR DLX storage geyser, and the geyser finder
- Bajaj: Shield series Crest Plus storage water heater
- Bajaj: Aquaquick instant water heater
- AO Smith India: storage water heaters
- Havells: Monza Pro storage water heater