Portable ACs are not free to run, but they are controllable. You pay for the hours the compressor works — so sizing, sealing, and timers matter more than the sticker price alone.
Rough cost sketch
- Find the unit’s input power in watts (or kW) on the label / manual.
- Multiply kW × hours used × your unit rate (p/kWh).
Example: a ~1.0 kW draw for 5 hours at 28p/kWh ≈ £1.40 that day. Heatwave weeks add up; mild evenings do not.
Exact wattage varies by model and mode. Treat this as planning maths, then check the product page for the rated input.
Habits that cut the bill
- Pre-cool with a timer instead of running all day empty-house
- Seal the window kit so cold air stays in
- Close doors to the room you’re cooling
- Use sleep / eco modes overnight
- Don’t undersize — an undersized unit runs flat-out longer
Class A and R290
Energy class and modern refrigerants help efficiency and environmental impact, but usage pattern still dominates cost. A sealed Class A unit used smartly beats a leaky “powerful” unit left on 24/7.
Buy with running cost in mind
Compare BTU, noise, and features on our table, then confirm live Amazon UK pricing and wattage on the listing before you commit.