Is air conditioning expensive to run?
People imagine air conditioning as an energy hog. Modern inverter systems tell a very different story — here are the real numbers.
The fear that air conditioning will "cost a fortune to run" comes from old, inefficient units and hot-country stereotypes. A modern UK system is a different animal. Here's what it actually costs.
Cooling costs: pennies, not pounds
A typical modern wall unit cooling a bedroom draws around 0.5–0.8kW once it's reached temperature. At an electricity price of about 25p per kWh, that's roughly 12–20p an hour. Cooling a bedroom for a few hours before bed on a hot night costs less than a cup of coffee.
Heating costs: where it gets clever
This is the part most people miss. In heating mode, an air conditioner is a heat pump, and heat pumps are typically 300–400% efficient. For every 1kW of electricity, you get 3–4kW of heat. That means heating a room with a modern AC unit can cost less than a plug-in electric heater, which is only 100% efficient.
| Heat source | Efficiency | Relative running cost |
|---|---|---|
| Plug-in electric heater | 100% | Highest |
| Gas boiler | ~90% | Moderate |
| Heat-pump air conditioning | 300–400% | Lowest |
How to keep costs low
- Use the timer — cool or heat only when you're in the room.
- Set a sensible temperature (around 24°C cooling, 20°C heating) rather than extremes.
- Keep filters clean — a clogged filter makes the unit work harder.
- Choose an A+++ inverter model, which ramps up and down smoothly instead of switching fully on and off.
The efficiency point matters most. A properly-sized A+++ system is the single biggest factor in low running costs. Oversized units short-cycle and waste energy — which is why we size carefully rather than selling you the biggest unit.
Frequently asked questions
How much does it cost to run air conditioning all day?
For an average room, expect roughly 12–20p per hour once it reaches temperature. Running one unit for 8 hours might cost around £1–£1.50, though it uses less once the room is stable.
Is it cheaper to heat one room with AC or with central heating?
If you only need to heat one or two rooms, a heat-pump air conditioner is usually cheaper than firing up a whole gas central heating system, because you heat only the space you're using at very high efficiency.
Thinking about air conditioning?
ClimaTight gives free, no-obligation quotes across Rochdale, Bury, Oldham, Heywood and Middleton.