Which is more energy efficient: heating a given volume of water all at once, or in two batches?
I have an electric kettle, and a large urn of room temperature filtered water, which I use for tea. If I'm making tea for two people who aren't going to be drinking it at the same time, is it more energy efficient to boil the water separately, all at once, or no difference?
@Fishercat Heating 400ml of water to a boil will take exactly twice the energy of heating 200ml to a boil. In the latter case you'll need to heat the kettle itself twice, but that ought to be insigficant; or rather, choose one that's light weight and heats easily if you care about efficiency, and then it will be insigficant.
The main thing is to not heat more water than you need, which is where the bulk of the energy is spent.
@tfb Thank you!
I do have a lightweight kettle, where the heating element is in direct contact with the water. IIUC, that design & method of heating water is far more efficient than any where the vessel has to heat before the water does.
I never do heat more water than I need, both to avoid wasting that energy, and because reheating/reboiling water reduces the flavor of whatever you make with it.
Fishercat
Thomas