Kettle Vs Microwave For Heating Water
Assumptions: 3kW kettle for 3 minutes versus 1kW microwave for 3-5 minutes.
| Scenario | Kettle | Microwave | Likely better choice |
|---|---|---|---|
| One mug | Often 2p-4p | About 1p-2p | Depends on volume |
| Several mugs | Kettle practical | Multiple runs | Kettle |
| Overfilled kettle | Wastes energy | Measured mug | Microwave may win |
Cost comparison
The biggest kettle waste is boiling more water than needed.
When each option wins
Microwaves can be efficient for a measured mug, but heating can be uneven and less convenient for tea.
What can change the result
For several drinks, a kettle is usually the practical choice.
FAQs
Which is cheaper for one cup?
It depends on water volume and time; both are only a few pence.
Does kettle wattage matter?
Higher wattage can boil faster, so total time matters.
Is reboiling wasteful?
Yes, repeated reboils add avoidable cost.
Should I microwave tea water?
Cost is not the only factor; taste and convenience matter.
Last reviewed 3 May 2026. Source: Ofgem energy price cap. Figures are estimates. Actual prices vary by region, supplier, tariff, payment method and meter type.