The cost of running Air Conditioning in the UK depends on the type of unit, how long it’s used each day, and the current electricity price.
More and more households are installing Air Conditioning without understanding the impact on their energy bills.
This guide explains typical running costs based on the latest Ofgem energy price cap, with a detailed cost table and calculator to help you work out what to expect.
You’ll also see how portable, split, multi-split, and central systems compare in terms of efficiency and cost.
UK Electricity Prices (July–September 2025 Price Cap)
Air Conditioning running costs are based on electricity prices, which Ofgem regulates under the Energy Price Cap.
From 1 July to 30 September 2025, the average electricity rate is 25.73 pence per kilowatt-hour (kWh), with a daily standing charge of 51.37 pence.
The total price cap for a typical household using both electricity and gas is £1,720 per year when paying by Direct Debit.
While Air Conditioning runs on electricity rather than mains gas, this combined figure helps illustrate the overall cost of energy in UK homes.
Actual prices may vary by region, tariff, and meter type, but the figures in this guide reflect standard national averages.
How Much Electricity Does Air Conditioning Use?
Electricity use varies by the type, size, and efficiency of the unit, along with how long it runs each day.
Power is measured in kilowatts (kW). The longer the Air con unit runs, the more energy it consumes.
A small portable Air Conditioning unit may use between 0.9 and 1.2 kW, while a medium split system might use 1.2 to 2.0 kW. Larger systems, such as multi-split or central setups, can draw 3.0 kW or more.
Efficiency plays a major role. Inverter-driven split systems adjust output automatically and use less energy than basic portable units, which run at full power whenever switched on.
The better the energy efficiency ratio (EER) or coefficient of performance (COP), the more cooling you get for each unit of electricity.
Usage habits also make a difference. Running a unit for a few hours in the evening costs far less than leaving it on all day.
Room size, insulation, and outside temperature all affect how hard the system has to work to maintain the desired temperature.
Understanding how much power your Air Conditioning unit uses is key to estimating the running cost.
The next section breaks down typical costs by unit type using the latest electricity rates.
Air Conditioning Running Cost Table (Summer 2025)
The table below shows the running costs for different types and sizes of Air Conditioning units, based on the electricity rate of 25.73p per kWh.
These estimates assume typical usage patterns and are designed to help you compare the cost of different systems.
(These figures are based on estimated power ratings and average daily use. Actual running costs may vary depending on insulation, room size, temperature, and the unit’s efficiency.)
| A/C Type | Cooling Capacity (BTU) | Power Consumption (kW) | Cost Per Hour | Cost – 4 hrs/day | Cost – 8 hrs/day | Monthly Cost (30 days) |
|---|---|---|---|---|---|---|
| Small Portable Unit | 7,000–9,000 BTU | 0.9–1.2 kW | 23.16p–30.88p | £0.93–£1.24 | £1.86–£2.47 | £27.90–£74.10 |
| Medium Portable Unit | 10,000–12,000 BTU | 1.3–1.6 kW | 33.45p–41.17p | £1.34–£1.65 | £2.68–£3.29 | £40.20–£98.70 |
| Large Portable Unit | 14,000 BTU | 1.8–2.0 kW | 46.31p–51.46p | £1.85–£2.06 | £3.70–£4.12 | £55.50–£123.60 |
| Small Split Unit | 9,000 BTU | 0.6–0.9 kW (inverter) | 15.44p–23.16p | £0.62–£0.93 | £1.23–£1.86 | £18.60–£55.80 |
| Medium Split Unit | 12,000 BTU | 1.0–1.3 kW (inverter) | 25.73p–33.45p | £1.03–£1.34 | £2.06–£2.68 | £30.90–£80.40 |
| Large Split Unit | 18,000 BTU | 1.5–2.0 kW (inverter) | 38.60p–51.46p | £1.54–£2.06 | £3.09–£4.12 | £46.20–£123.60 |
| Multi-Split (2–3 rooms) | 24,000–36,000 BTU | 2.5–3.5 kW | 64.33p–90.06p | £2.57–£3.60 | £5.15–£7.20 | £77.10–£216.00 |
| Central Air System | 48,000–60,000 BTU | 4.0–5.0 kW | £1.03–£1.29 | £4.12–£5.16 | £8.24–£10.32 | £123.60–£309.60 |
Air Conditioning Running Cost Calculator
Want to get a clearer idea of what your Air Conditioning costs to run? Use the calculator below.
- Select the type of Air Conditioning unit
- Enter how many hours it runs per day
Your estimated daily, monthly, and seasonal costs will appear, based on the current electricity rate of 25.73p per kWh.
The calculator uses realistic power ratings for common unit types to give you a quick and useful guide.
Whether you’re using a portable unit in a single room or a split system throughout the evening, you can adjust the inputs to match your usage pattern.
Air Conditioning Running Cost Calculator
Types Of Air Conditioning Units
There are several types of Air Conditioning systems available. Each has its own features, running costs, and suitability depending on your property and needs.
Portable Air Conditioners
Portable units are affordable and easy install, usually needing just a power socket and a window for the exhaust hose. They’re ideal for single rooms but are less efficient than other systems.
They use more electricity for the amount of cooling they deliver and often need to run for longer, which makes them more expensive to operate over time.
Split Air Conditioning Systems
Split systems are fixed units with an indoor and outdoor component. They offer better performance and far greater efficiency than portable units, especially inverter models that adjust output automatically.
They’re quieter, more powerful, and cool spaces quickly. While they do require professional installation, they’re a solid choice for regular use and can be more cost-effective long-term.
Multi-Split Systems
Multi-split systems connect multiple indoor units to an outdoor condenser. They’re a great option if you want to cool several rooms individually, such as bedrooms and a lounge.
Installation is more complex and costly than a single unit, but these systems are still efficient and offer room-by-room control. They’re best suited for larger homes or anyone needing zoned cooling.
Central Air Conditioning
Central Air Conditioning systems are more common in large homes or commercial buildings.
They cool the entire property through ductwork and are powerful, but expensive to install and run.
For most UK homes, central systems aren’t necessary unless there’s already ductwork or a high cooling demand. In most cases, split or multi-split systems are the better option.
Tips To Reduce Air Conditioning Running Costs
There are a few easy ways to reduce Air Conditioning costs without sacrificing comfort.
Choose The Right Size Unit
Using the correct size for your room is key. An oversized unit wastes energy, while an undersized one will struggle and run constantly.
Keep The Heat Out
Shut windows and doors while the unit is on, and keep blinds or curtains closed during the hottest times of day.
Maintain Your System
Clean or replace filters periodically to improve airflow and efficiency.
Avoid Overcooling
Set the temperature to a comfortable level—there’s no need to make it colder than necessary.
Use Timers And Thermostats
Use timers and thermostats to control how long your system runs. In most cases, you won’t need it on constantly, especially at night.
Need Professional Air Conditioning Installation In Essex
If you’re considering Air Conditioning for your home or business in Essex, we offer installation for all system types, including split, multi-split, and ducted setups.
Our qualified engineers will assess your space, recommend the best system, and complete the installation to a high standard.
We fit reliable, energy-efficient units designed for long-term performance and low running costs.
Whether you’re cooling a single room or several zones, we’ll ensure everything is correctly specified and professionally installed.
All work is fully insured and completed to current regulations. Get in touch for a free, no-obligation quote or to discuss your options.
Hi, I’m Terry, the founder and owner of TM Hughes & Son Gas Services
Please get in touch to book an appointment or receive a free, no-obligation quote
Call – 01245 830075
Email – info@tmhughesandson.uk
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