How much does air conditioning cost to run in the UK?
Cooling a typical bedroom or living room costs roughly 15–40p per hour at current electricity prices, depending on the unit size, the temperature outside and how hard it's working. Used sensibly (cooling the room you're in, doors closed, a realistic set-point), a UK summer's cooling usually totals tens of pounds, not hundreds. In winter the same unit heats the room at roughly a third of the cost of electric radiators, because heat pumps move heat rather than generate it.
What drives the cost
Three things: the unit's efficiency rating (look at SEER for cooling, SCOP for heating), the gap between outside temperature and your set-point, and habits — cooling an empty house or fighting an open window is where money disappears.
The winter flip-side
An air-to-air heat pump typically delivers three-plus kilowatts of heat per kilowatt of electricity. For heating one room — a home office, a bedroom — it's usually the cheapest option available, and it's why these systems make sense year-round in the UK.
Honest sizing saves money twice
An undersized unit runs flat-out and struggles; an oversized one short-cycles inefficiently. Correct sizing at the survey is the single biggest running-cost decision — and it's why we size to the room, not the invoice.