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The quick comparison
| Storage geyser | Instant geyser | |
|---|---|---|
| Usual size | 6 to 25 litres | 1 to 6 litres |
| Usual power | About 2000 watts | About 3000 watts |
| Waiting time | About 10 to 25 minutes | A minute or so |
| Suits | Bathing, families | Kitchen sink, one quick wash |
| One after another baths | Yes, if the tank is big enough | No |
| In a power cut | Tank stays warm for some hours | No heating without power |
| Heat lost while it sits | More, since it holds more water | Less, since it holds little |
| Wall space | Needs more | Needs less |
| Wiring | Normal geyser point | Ask an electrician to check first |
These are usual figures, so read the label on the model you are looking at.
How each one works
A storage geyser heats a tank of water and then holds it. You switch it on, wait, and take hot water as you need it. The tank is insulated, so the water stays warm for a while after it switches off.
An instant geyser also has a small tank in most cases, but it uses more power to heat those few litres quickly. The word "instant" can mislead. It does not give you a long hot bath. It gives you a short supply of hot water, fast.
What your home needs
Think about how you use hot water on a normal winter morning.
- Family of three or four, bathing with a bucket or shower. One after another, you need a tank of hot water. A 15 litre storage geyser is a common choice.
- Five or more people. Look at 25 litres, or one geyser for each bathroom.
- One person, one quick wash. A smaller storage geyser or an instant geyser can do the job.
- Kitchen sink. Instant suits this well, since you need a small amount of warm water for a short time.
- Small flat with little wall space. Measure first. A 25 litre tank may not fit above a door or a shower.
You mix geyser water with cold, so the hot water goes further than the tank size suggests. These are rough guides, and your own habits matter more.
What it costs to run
One unit on your bill is one kilowatt-hour. This table uses an example rate of ₹8 per unit. Your rate depends on your state and how much you use, so check your bill.
| Geyser power | Time on | Units | Cost at ₹8 |
|---|---|---|---|
| 2000 watts | 15 minutes | 0.5 | ₹4 |
| 2000 watts | 30 minutes | 1 | ₹8 |
| 3000 watts | 10 minutes | 0.5 | ₹4 |
| 3000 watts | 20 minutes | 1 | ₹8 |
The same units cost the same money, whichever geyser uses them. A higher wattage heats faster and switches off sooner. What you pay for is how much water you heat.
As an example, a 2000 watt geyser that runs for 30 minutes a day uses 30 units a month, or about ₹240 at ₹8. Expect more in December and January, since the incoming water is colder.
A storage tank also loses some heat while it sits. So switch it on before you need hot water and off once it is heated. On a storage geyser, BEE stars mostly show how well the tank holds heat. They matter more if water sits in the tank between baths.
Wiring and safety
- Earthing. Get an electrician to confirm the point is properly earthed.
- RCCB or ELCB. This device cuts the power if current leaks. Check that your bathroom circuit has one.
- Load. Use a socket and wire rated for the wattage, and never an extension board. This matters even more with a higher wattage geyser.
- Safety valve. Do not block or remove it.
- Inverter. Most home inverters cannot run either type, so plan for power cuts.
Hard water
If your water leaves white marks on taps, scale can build up on the element and inside the tank. Read what the listing says about the tank lining and anode rod, and ask how often the rod should be checked.
Which should you choose?
Choose a storage geyser if you need hot water for bathing, two or more people bathe one after another, you get power cuts in the morning, or you have a normal geyser point and enough wall space.
Choose an instant geyser if you want warm water at a kitchen sink, one person needs a quick wash, you have little wall space, and an electrician has confirmed your wiring can take the load.
Consider both if you want a storage geyser for the bathroom and something small for the kitchen. Many homes need hot water in both places, and one geyser rarely reaches both well.
Options to look at on Amazon
We have not tested these. Both are 15 litre storage listings, the common size for three or four people. They are in no particular order, and the details come from the listing titles. Check the current price, warranty and reviews on Amazon, and look elsewhere if you need another size.
| Product | Type | Listed detail |
|---|---|---|
| Crompton Arno Neo | Storage | 15 litres, 5 star |
| AO Smith VAS PLUS | Storage | 15 litres, 2KW |
Before you buy
Ask who will install it, and what the price of pipes, stand and valve will be. Installation is often charged separately. Check that a service centre covers your area too.
The products in this comparison
Crompton Arno Neo
AO Smith VAS PLUS
Read next
Common questions
Does an instant geyser give hot water without stopping?
Usually not. The electric instant geysers in this guide are small tanks of about 1 to 6 litres that heat quickly. Once those few litres are used, the water coming out starts to cool.
Does a higher wattage geyser cost more to run?
Not for the same water. A higher wattage geyser heats faster and switches off sooner. What you pay for is how much water you heat, and by how much.
Can an instant geyser go on a normal point?
Ask an electrician to check first. An instant geyser often draws about 3000 watts, which is more than a storage geyser, so the wire and socket must be rated for that load.