induction stove

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If you cook in normal stove 1 liter of water, it may take around 10–15 minutesto boil depending upon the stove that you are using.

If you use Water Heater to cook 1 liter of water it takes around 4–5 Minutesto boil a liter of water. (Of course it also differs from water heater to water heater)

If you want it super fast, usually microwave oven takes around 3–4 minutes to boil water ( I used the level 5 power and it is a normal microwave oven).

Vs an electric 2400W (so they say) heater
couldnt boil water without a lid.