Air conditioners ranked by cost to run
The number that matters: cost per hour to run. We rank portable, window, split and mini-split air conditioners by running cost — not just sticker price — so you can see the real cost at a glance.
Air conditioning buying guides
See all guides →- How much does it cost to run an air conditioner? The simple cost-per-hour formula, typical UK & US costs, and how to cut your bills.
- What size air conditioner do I need? BTU by room size Match cooling capacity to your room in m² or sq ft — and avoid wasting money.
- Which air conditioner type should you buy? Portable, window, split or mini-split — a decision guide, plus every head-to-head comparison.
- SEER vs EER: efficiency ratings explained What EER, CEER, SEER and SEER2 measure, and how each maps to running cost.
Plus head-to-head type comparisons (split vs mini-split, portable vs split), electricity use, inverter vs non-inverter and more — browse all guides →
Frequently asked questions
How is the cost per hour to run calculated?
Cost per hour = the unit's rated power in kilowatts × your local electricity rate. Where a manufacturer doesn't publish the power draw, we estimate it from the BTU and the typical efficiency for that AC type, and flag it as estimated.
Which type of air conditioner is cheapest to run?
For the same cooling power, ductless mini-splits are cheapest to run, then window units, with portables the most expensive per hour. Use the Type filter to compare within a category.
What size air conditioner (BTU) do I need?
As a rough guide, allow about 450 BTU per square metre (20 BTU per sq ft), with more for sunny rooms, high ceilings or kitchens. Try the BTU calculator for a recommendation for your room.
Are portable air conditioners expensive to run?
Portables are the least efficient type, typically drawing 1–1.8 kW for 9,000–14,000 BTU, so they cost more per hour than a window or mini-split unit of the same cooling power.
Do the running costs change by country?
Yes. Switch between the UK and USA and the cost per hour recalculates at local electricity rates, shown in local currency.
