What is the cost per unit ratio of boiling water in a kettle - compared to boiling water using a gas boiler?

Question

What is the cost per unit ratio of boiling water in a kettle - compared to boiling water using a gas boiler?

Answer 1

Electricity is maybe 4x or so more expensive than wholesale price of natural gas, but retail gas price can be up to 3x higher than wholesale. In theory, gas heater would be somewhat lower cost. In practice, wasting a bunch of water to get hot water at the faucet means you heat a lot of water to get a couple of cups of hot water. Plus, water heater is usually well under 60°C (140°F), so you still have to heat the water more than 1/2 the temperature rise to get it to boil. End result is that water from heater generally more expensive. Plus it wastes water.

To heat 300ml of water (about a quart and a half) 70°C to boil takes 300g * 4.186 J/gC° * 70°C = 88 kW*s = 0.02kW*hr. At  $0.11 per kW*hr, this is 0.3 cents. In other words, kettle is probably a little cheaper,  but cost is so small, it doesn't matter.

Answer 2

in the US gas (especially piped natural gas as opposed to propane) works out very significantly cheaper

at least half the cost of electrical heating

for a more accurate answer one would need to know your local prices of gas, electricity and the exact way of heating the water

r we dealing with a stove top, electric kettle, (how efficient is the heat transfer from source to water and insulation values and time to desired temperature etc)