Split air conditioners ranked by cost to run
Fitted wall-mounted split systems with an indoor and outdoor unit. Ranked by what they cost to run per hour.
- Typical efficiency
- SEER 16–20
- Power (12k BTU)
- ~1,000–1,100 W
- Cost/hr (UK)
- ~£0.25–0.27
- Install
- Pro · £400–1,000
- Noise
- 19–35 dB
Typical figures for a 12,000 BTU unit at UK rates (£0.245/kWh) — see the live listings below for exact specs per model.
Guides for split air conditioners
Split air conditioners: frequently asked questions
How much does a split air conditioner cost to run?
Fitted split systems average an EER around 11 and most are inverter-driven, so they modulate output instead of cycling on and off. A 12,000 BTU split draws about 1,050 W flat out — roughly £0.26 per hour at UK rates — but usually far less in practice because the inverter throttles back once the room is cool.
Are split air conditioners more efficient than portables?
Significantly. A split’s EER (~11) plus inverter control means 30–50% lower running cost than a single-hose portable of the same capacity. The trade-off is a fixed installation with an outdoor unit.
Can a split air conditioner also heat a room?
Many can. A reverse-cycle (heat-pump) split delivers heating at a COP of 3–4 — that is 3–4 kW of heat per kW of electricity — cheaper than electric resistance heating and competitive with gas. Look for the heat-pump badge in the table.
