Tool
Running cost calculator
Cooling kit is sold on the shelf price. What almost nobody publishes is what it costs to run through a British summer, in pounds. This does.
The rate starts at 26.11p per kWh, the Great Britain average for direct debit customers under the Ofgem price cap. It is an average and it changes every quarter, so your own bill is the better number.
What it costs
No electricity unit rate has been entered, so every figure below is zero. Put the per kWh rate from your bill into the last field.
- Per hour
- Per night
- Per summer
| Purchase price | |
|---|---|
| Running cost, one summer | |
| First year |
A cheap unit that runs all night is not a cheap unit. The figure that matters when comparing two machines is the one at the bottom of that table, not the one on the box.
Questions
- Why does the first year total matter more than the price?
- Because a cheap unit that runs all night is not a cheap unit. Two machines a hundred pounds apart on the shelf can be the other way round by September. The figure worth comparing is purchase price plus a summer of running, which is why they are shown together.
- Where do I find my unit rate?
- On your electricity bill or in your supplier's app, quoted in pence per kWh. It is not the standing charge, which you pay whether the unit runs or not and which therefore does not belong in this calculation.
- How many nights should I put in?
- Fewer than instinct suggests. A British summer delivers a handful of genuinely hot spells rather than a continuous season, so a number in the tens is usually closer than a number in the hundreds. If you want the pessimistic case, run it twice.
- Does this account for the unit cycling on and off?
- No, and that matters. A thermostatically controlled unit draws its rated power only while the compressor is running, so a real bill is usually lower than the figure here. Treat this as the upper bound rather than the expected cost.
- Where does the electricity rate come from?
- The field starts at 26.11p per kWh, the Great Britain average for direct debit customers under the Ofgem energy price cap, read from ofgem.gov.uk on 1 August 2026. It is a national average and it moves every quarter, so your own bill beats it. Type your rate over it and every figure updates.