As UK summers become warmer and heatwaves more frequent, air conditioning is no longer seen as a luxury. Homeowners, landlords and businesses across the UK are increasingly installing air conditioning systems to improve comfort, heating and cooling in one system, efficiency and indoor air quality. However, one question always comes up first: AC running costs.
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Understanding the real cost of running air conditioning in the UK depends on several factors, including electricity prices, system efficiency, room size, usage patterns, and type of air conditioning unit. In this guide, we break down everything you need to know about air conditioning running costs, with realistic UK examples and clear explanations.
AC running costs refer to the electricity consumption of an air conditioning system while cooling (and sometimes heating) a space. These costs are usually calculated in kilowatt-hours (kWh) and multiplied by the current UK electricity unit rate.
As of recent years, average UK electricity prices typically range between 22–30 pence per kWh, depending on your tariff, energy supplier, and whether you’re on a fixed or variable deal.
Simple formula: AC running cost = Power consumption (kW) × hours used × electricity price (p/kWh)
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Average Air Conditioning Running Costs
in the UK
Here’s a rough guide to typical AC running costs per hour in the UK:
AC Unit Size
2.5kW (small room)
3.5kW (medium room)
5kW (large room)
Power Usage
0.6-0.7kW
0.8-1kW
1.2-1.4kW
Cost Per Hour (25p/kWh)
15-18p
20-25p
30-35p
These figures assume a modern air conditioning system, not older units.
What Affects AC Running Costs?
Factors such as usage patterns, efficiency settings and your properties' insulation levels all affect your air conditioning running costs and so, there are ways of ensuring you get the most value for money out of your system.
Building Insulation and EPC Rating- Well-insulated properties with double or triple glazing, Insulated walls and lofts and good airtightness require significantly less cooling and heating energy.
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Thermostat Settings- Every degree lower in cooling mode and higher in heating mode increases electricity consumption. The most efficient comfort range is 21–23°C.
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Usage Patterns- Continuous low-level operation is more efficient than switching systems on and off repeatedly.
Maintenance and Servicing- Annual servicing ensures clean filters, correct airflow, optimal refrigerant charge and therefore, maximum efficiency. Poorly maintained systems can consume 10–25% more electricity.
How to Minimise AC Running Costs Further
There are a few ways to reduce AC running costs and getting the most efficiency out of your system is more important than ever. Ensuring that you use a professional Refcom registered engineer to install a correctly sized system for your room or home is one way of minimising the running costs.
Also, using programmable thermostats, keeping curtains and blinds closed during peak sunlight hours if in cooling mode, scheduling regular maintenance and keeping doors closed between zones are all effective ways of reducing the cost of running your AC unit.
Another effective way of reducing your AC running costs is installing solar PV alongside the AC system which will reduce your reliance on the grid for electricity.
Conclusion: AC Running Costs in the UK
Modern air conditioning systems are among the most efficient cooling and heating solutions available in the UK today. When professionally installed, they offer predictable, low running costs, exceptional energy efficiency and minimal environmental impact.
For most UK homes and businesses, AC running costs typically range from 15–35p per hour, making air conditioning both affordable and sustainable.
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