Running cost calculator
What does air conditioning cost to run?
Less than most people expect. A cool night's sleep in a typical bedroom costs about 44p at today's prices. Put in your postcode and how you'd use it, and see your own figures.
Electricity at 25.4p per kWh: today’s Flexible Octopus price for East Midlands, from Octopus Energy.
A cool night's sleep
44p
8 hours of cooling in a 4 × 3.5 m bedroom, Essential 2.0 kW
Cooling for the summer, 60 days
Heating for the winter, 150 days
Worked out with the unit at full sized load every hour it’s on, so real costs are usually lower. Unit prices only; standing charges you pay anyway.
How we work it out
Each room is sized the way we size it at a survey, and paired with the unit we’d fit from the system you choose. We divide the room’s cooling or heating load by the unit’s seasonal efficiency (SEER for cooling, SCOP for heating) to get the electricity it uses, then multiply by today’s price for your area.
The saving compares a year of air con with what you’d otherwise use: a portable unit in summer, and electric heaters or gas central heating in winter. Our more efficient systems cost more to fit and less to run. If you’ll use air con a lot, especially as your main heating in a living room or conservatory, Comfort and Premium can pay back their extra cost over Essential in around five years. For lighter use, Essential is the best value. Pick a system above and the calculator shows how long it takes for your use, and which system is cheapest over ten years.
We assume the unit works at the room’s full load every hour it’s on. In practice it slows right down once the room reaches temperature, so most people’s costs come in lower. The comparisons use the same load, so they’re like for like.
Prices are Flexible Octopus prices for East Midlands: electricity at 25.4p and gas at 7.8p per kWh, checked daily with Octopus Energy until you add your postcode. Your own costs depend on your tariff, the weather, how well the room holds its temperature and how warm or cool you like it. For prices to buy and fit, use the cost estimator.
Questions people ask
How much does air conditioning cost to run per hour?
Cooling a typical 4 × 3.5 m bedroom costs about 5p an hour once it's up to temperature, and a 5 × 4 m living room about 9p. Heating the same bedroom costs about 8p an hour. These are at today's electricity price in Derbyshire; enter your postcode above for yours.
Is it expensive to run air conditioning overnight?
No. Eight hours of cooling in a typical bedroom costs about 44p at today's prices, and a whole summer of hot nights about £26.
Is air conditioning cheaper to run than a portable unit?
Much cheaper. A fixed split system is rated for seasonal efficiency (SEER) of 6 to 8.6, while a typical A-rated portable unit manages about 2.6, and loses some of its cooling through the hose. For the same cooling, a portable unit uses two to three times the electricity.
Is heating with air conditioning cheaper than gas?
At today's prices in Derbyshire, a kWh of heat costs about 6p from our Essential system, against 8.7p from a 90% efficient gas boiler and 25.4p from an electric heater.
Where do the electricity prices come from?
From Octopus Energy's public price list, checked daily. We use Flexible Octopus, their standard variable tariff, because it follows the Ofgem price cap closely, so it's a fair guide whoever supplies you. Your postcode tells us your electricity region, as prices differ slightly around the country.
Cool summers that don't cost the earth
We'll visit within 5 working days, measure up, and send you a fixed written price. Free, and no obligation.