The average cost to run a standard air conditioning unit in the UK is between 20p to 50p per hour, depending on the size, energy efficiency, and type of system installed. For a typical 2.5kW split system, this equates to £1.60 to £4.00 per day, assuming 8 hours of use.
However, the real cost of running air conditioning depends on more than just electricity; factors such as installation, energy savings, and usage habits also play a role.
In this guide, we’ll break down how much air conditioning costs to run, what affects these running costs, and whether it’s worth it for UK homeowners and businesses.
Quick Summary
- Typical cost to run air con: 20p–50p per hour
- Daily cost (8 hours use): £1.60–£4.00
- Monthly estimate (moderate use): £50–£120
- Split systems and ceiling-mounted units are more efficient than older models
- Rising energy prices can impact long-term air conditioning running costs
Now, let’s dive into the details!
Is Air Conditioning Expensive to Run in the UK? Or More Affordable Than You Think?
While many UK homeowners assume air con is a luxury with high running costs, the reality is more balanced. For most households using a modern, energy-efficient split system during warm months, daily running costs are comparable to using a kettle or oven and far less than full central heating in winter.
In fact, energy-efficient systems used wisely can keep your space or home cool for under £2 per day.
For comparison:
- A typical AC unit for a bedroom might cost £1.60–£2.00/day in summer months.
- A central heating boiler in winter can cost over £5–£10/day to run.
So, is air con more expensive than heating?
Not necessarily, it depends on how it’s used. Cooling tends to be more targeted and seasonal, whereas heating is typically required for longer periods across larger areas.
Air Conditioning System Types (and How Much They Cost to Run)
One of the key influences in how much it costs to run air con, is the type of air conditioning you have.
There are several common types of air conditioning systems in the UK, each with different upfront and running costs. Here’s a rundown of each type and its typical running costs:
| Type of Air Conditioner | Typical Usage | Typical Running Cost per Hour | Notes |
| Split System (Wall-mounted) | Homes, offices | 20p–35p | Most energy-efficient choice; includes indoor + outdoor unit |
| Ceiling-mounted Cassette Unit | Larger commercial/retail spaces | 30p–50p | Higher output for large spaces; efficient for zoned cooling |
| Ducted System | Whole-house/commercial use | 40p–60p | Great for full-building climate control but higher upfront and running costs |
| Multi-Split System | Whole homes, flats, small offices | 30p–50p (total) | One outdoor unit supports multiple indoor wall-mounted units. Ideal for zoned cooling across multiple rooms. |
| Window Unit | Rare in the UK | 30p-45p | Older style, often noisy and less efficient. Rarely installed in UK homes now. |
What Impacts the Cost of Running Air Conditioning in the UK?
1. Type of Air Conditioning System
- Split systems and ceiling-mounted units are commonly used for residential homes and commercial spaces. These are more energy efficient than older types such as window units.
- The installation costs are higher for fixed systems, but the operating costs tend to be lower over time compared to portable or temporary alternatives.
2. Energy Efficiency Ratings
- Look for AC units with a high SEER (Seasonal Energy Efficiency Ratio) or those rated A+++.
- Efficient systems use less electricity per hour, resulting in lower energy bills over time.
3. Usage Habits
- Running your air conditioner all day will increase electricity usage significantly.
- Using timers, thermostats, or smart controls helps optimise energy consumption.
4. Energy Prices in the UK
- With fluctuating energy costs, particularly since 2022, even a small difference in your system’s efficiency can lead to large savings annually.
How Much Does It Cost to Run an Air Conditioner for 1 Hour?
A standard 2.5kW air conditioning unit consumes approximately 0.7–1.2 kWh per hour, depending on the temperature and usage settings. Based on an average UK electricity rate of 30p per kWh (as of 2025), this means:
- Low usage (efficient model): 21p/hour
- Moderate usage: 30–36p/hour
- High output mode: Up to 50p/hour
Larger systems or poorly maintained AC units will naturally cost more to operate.
Is It More Economical to Leave Air Conditioning On?
This is one of the most frequently asked questions from UK homeowners, especially during heatwaves. The idea that leaving your air conditioner on all day at a steady temperature is more efficient than turning it off and on again is a common myth (just like the myth that air conditioning is always bad for you!)
The Truth? No. It’s almost always more economical to turn off your air conditioner when not needed, rather than leaving it running continuously at a low temperature.
Why?
- AC units use energy whenever they’re on, even if they’re maintaining a set temperature. So running it all day adds up, especially when you’re not home to benefit from it.
- While older systems had to work hard to cool rooms from scratch, modern inverter-based air conditioning units are designed to adjust output gradually, using less power when maintaining the set temperature or restarting after a short break.
- Short cooling cycles timed to your schedule are far more efficient than constant operation.
If you’re leaving for several hours, it’s far better to turn the system off entirely or set it on a timer or eco mode so it only runs when needed.
Tip: Use a smart thermostat or app-based control to automate your cooling schedule and avoid wasting energy on empty rooms.
Cost-Saving Tips for Running Air Con in the UK
Want to cool your home or office without a high energy bill? Try these top cost saving tips:
1. Use Timer or Smart Controls
Set your air conditioner to turn off automatically after you fall asleep or leave for work.
2. Keep Doors and Windows Closed
Prevent warm air from entering and cool air from escaping. It sounds simple, but it works.
3. Regular Maintenance
Clean filters monthly and service units yearly to keep them running efficiently.
4. Shade and Insulate
Close blinds during the hottest parts of the day and insulate rooms to retain cool air longer.
5. Use Fan + AC Combo
Fans help circulate cool air so you can raise the thermostat by a few degrees without losing comfort.
Is Air Conditioning Worth It in the UK?
Here are a few reasons why air conditioning can be a cost-effective choice, especially in modern UK homes:
- Hotter summers are increasing the demand for reliable cooling options, even in typically temperate regions.
- Modern systems often provide both heating and cooling, making them useful all year round.
- In well-insulated homes, energy-efficient AC use can help keep costs low and reduce reliance on central heating during transitional seasons.
- Smart features and inverter technology reduce energy waste by adjusting performance based on real-time temperature needs, offering greater comfort with less energy.
Final Thoughts
So, how much does air conditioning cost to run in the UK? For most homes, it’s surprisingly manageable. Daily use during summer typically adds £40–£120 per month to your energy bills, but with smart usage and an efficient system, this can be a cost-effective way to stay comfortable.
Ultimately, the cost depends on your system type, usage habits, and energy efficiency. With modern air conditioning units, it’s entirely possible to stay cool without breaking the bank, even with rising energy prices. For homes or workplaces that need reliable climate control, the long-term comfort, control, and energy savings often outweigh the running costs.
At Eaglereach Mechanical, we specialise in energy-efficient air conditioning installation, maintenance, and repairs, helping you keep your running costs low while staying comfortable all year round. Whether you’re considering a split system for your home or need expert advice on optimising your current setup, our experienced team is here to help.
Contact us today for a free consultation or to schedule a service visit.
Disclaimer
All cost estimates in this article are based on publicly available UK energy rates (averaging 28p–33p per kWh in 2024–2025) and typical usage patterns for domestic air conditioning systems. Actual running costs may vary depending on:
- The type and size of your air conditioning unit
- Local energy tariffs and time-of-use rates
- Room insulation, outdoor temperatures, and system efficiency
- Installation quality and maintenance
For an accurate assessment, consult your energy provider or a qualified HVAC engineer.
FAQs about Air Conditioning in the UK
Does aircon use a lot of electricity in the UK?
Not necessarily. Efficient AC units can be run for a few hours a day at a cost comparable to household appliances like kettles or ovens.
Is it cheaper to run a fan or an air conditioner?
A fan uses less electricity (typically under 5p/hour) but does not actually reduce air temperature. Air conditioning is more effective for cooling, especially during heatwaves.
What temperature should I set my air conditioner to in summer?
The ideal setting for both comfort and efficiency is around 22–24°C. Every degree lower can increase energy consumption by up to 10%.
Do all air conditioning units cost the same to run?
No. Split systems and ceiling-mounted air conditioners tend to be more cost-effective in the long term than less efficient or older systems.
