How Much Does Air Con Cost to Run in the UK?

The UK broke its all-time May temperature record in 2026. This followed 2025, the UK’s warmest summer since records began in 1884. Uncomfortably hot spells are now becoming a regular part of British summers.

As a result, more households are looking for the cheapest way to cool a home in the UK. In fact, an estimated 4 million UK homes now have air con, double the figure from three years ago.

Is Air Con Expensive to Run in the UK?

How much does air con cost to run? It typically costs between 13p and £1.31 an hour, depending on the type of unit and how big it is. However, air conditioning running cost per hour depends on the unit type, your electricity tariff, how often you use it, the size of the space and how efficient your system is.

There are three main types of air con units to choose from:

• Portable units are freestanding, plug into any socket and work by drawing in warm air, cooling it, and venting heat outside through a pipe or ducting, which makes them the easiest option to set up in a rented home.
• Split systems pair a wall-mounted indoor unit with an outdoor compressor that vents the hot air outside, and are one of the most common choices for cooling one or more individual rooms.
• Ducted systems use a central unit to push cooled air through a network of ducting, with vents in each room. They are the most effective way to cool an entire home but require invasive renovation work and are the most expensive to fit. 

Air Con Running Cost at a Glance

Is air con expensive to run in the UK?

 Note: Figures reflect typical air con running costs UK households can expect at the current Ofgem price cap electricity rate of 26.11p/kWh, in place from 1 July to 30 September 2026. Costs will vary depending on your tariff.

Find out more about how the price cap works here.

How to Calculate Your Air Con Running Cost

How much electricity does air con use, and what does that mean for your bill?

Working out how much your air con costs to run only takes two numbers.

You need the power rating of your unit in kilowatts, usually listed on the energy label or in the product manual, and your electricity rate in pence per kWh, which you’ll find on your bill or, if you’re on a standard variable tariff, in the current price cap.

You can then use a simple calculation to work out how much air conditioning costs to run per hour:

Power (kW) x electricity rate (p/kWh) = air con cost per hour in a UK home.

How hot it is outside affects how hard your unit has to work to hit your target temperature. In the UK, real-world air con costs per hour will move around a bit even for the same unit.

Worked Example: Portable Air Con

Portable air con running costs for a typical 990W portable unit, running at the current price cap rate of 26.11p/kWh, are around 26p an hour:

0.99kW x 26.11p = 25.84p per hour.

Running it for eight hours a day comes to roughly £2.07 per day, or £14.48 per week.

These figures are based on the current Ofgem price cap and will update in October 2026.

Worked Example: Split Air Con (Single Room)

A 700W single-room split unit costs about 18p an hour at the same rate, working out to £1.46 per day over eight hours, or £10.24 per week:

0.70kW x 26.11p = 18.27p per hour.

That’s less than half the hourly cost of a portable unit doing the same job.

What Affects How Much Air Con Costs to Run?

How much does air conditioning cost to run per day from one home to the next? A handful of factors determine air con energy consumption in the UK, and whether your bill stays modest or creeps up. Most of them are within your control.

Your Electricity Tariff

Your electricity tariff is the single biggest factor behind air con running costs UK households face.

At the current Ofgem price cap, the unit rate is 26.11p/kWh. If you’re on a fixed tariff, your rate could be higher or lower, so it’s worth checking your bill rather than assuming the price cap applies to you.

If you have solar panels, running air con during daylight hours can draw on your own generated electricity instead of the grid, cutting your effective cost further. Find out more about solar panels here.

The Type and Size of Unit

Portable units use more electricity relative to the cooling they produce than split systems do. A correctly sized single-room split system is generally the most cost-effective option for regular use, and getting the size right matters just as much as the system type.

When it comes to air con energy consumption in the UK, the size of the room matters as much as the unit itself. Cooling a large room will naturally use more electricity than cooling a smaller room, so consider room usage patterns. High ceilings, large windows and rooms that catch a lot of direct sun all make a unit work harder too, so it’s worth factoring these in when choosing a system for your space, instead of just the floor area.

An undersized unit runs constantly trying to reach your target temperature, while an oversized one costs more than necessary to buy and to run.

A well-insulated room with double glazing holds onto cool air, so your unit doesn’t have to work as hard or run as long to maintain the temperature.

Energy Efficiency Rating

To make sure you’re investing in energy efficient air con for a UK home, look for the SEER rating, or seasonal energy efficiency ratio, when comparing units. The higher the rating, the less electricity a unit needs to produce the same amount of cooling.

A higher-rated system usually costs more to buy but noticeably less to run over a full summer than an older or budget model.

How You Use It

The temperature you set, the number of hours you run the unit each day, and whether you use features like ‘sleep mode’ will all impact the final cost.

Running at a consistent 18-21 degrees Celsius is more efficient than cooling a hot room from scratch each time. Timers and smart controls help keep both in check, so the unit only runs when you’re actually in the room rather than all day out of habit.

Portable vs Split Air Con: Which is Cheaper to Run?

It depends on which cost you’re looking at. Per hour, split air con is cheaper to run than portable. Factor in installation, and portable wins on total cost, at least in the short term. Plan to use air con every summer for years to come, and split wins again once that installation cost is spread out.

Portable units are the cheapest to buy, typically £350 for a 12000 BTU portable unit according to Checkatrade, and need no professional installation. You just plug it in and vent the exhaust hose through a window. Split systems cost more upfront: a 12000 BTU wall-mounted unit, recommended for a large space, runs £620 to £890. A typical fully-installed single-room system can cost £2,000 to £3,500, rising to £6,000 or more if you want it in multiple rooms.

That installation cost is exactly why portable wins on total cost early on, because there’s simply less to pay for upfront. However, it’s also why split wins the moment you’re looking at years rather than weeks. A split system’s lower hourly running cost, and the fact the heat extracted from the air won’t leak back into the room through the exhaust hose the way it does with a portable unit, mean the higher purchase and installation cost pays for itself over repeated summers.

How to Reduce Your Air Con Running Costs

A few habits make a real difference to air con running costs UK households see over a summer.

• Set your temperature to 18-21°C rather than as low as it will go
• Keep windows and doors closed while it’s running
• Use blinds or curtains to block direct sunlight during the hottest part of the day
• Clean or replace filters regularly, a clogged filter makes the unit work harder
• Use timers or smart controls so it only runs when you need it
• Cool the room you’re actually in rather than trying to cool your whole home

These small changes add up. For more ways to bring your bills down, see our full guide on how to save money on your energy bills.

Air Con vs Fan Cost: Which is Cheaper to Run?

A standard electric fan uses around 25-75W, compared with 500-1,000W for air con, which makes it roughly 10 to 20 times cheaper to run per hour.

A fan won’t lower the temperature of a room the way air con does, but for taking the edge off on a mild day, it’s by far the cheapest way to cool a home in the UK.

If you’re considering air conditioning, choosing the right system can make a real difference to both comfort and running costs. The habits covered above, steady temperatures, closed blinds, only cooling the room you’re actually in, keep those air con costs per hour down even further.

If your bills are genuinely difficult to manage this summer, air con is not a reason to take risks with your supply.

Tampering with a meter or bypassing your supply to save money, whether that’s for air con or anything else, is illegal and dangerous. Unsafe connections are a genuine fire and electric shock risk, not just to you but to your neighbours too.

Our guide to support schemes, grants and advice in 2026 can point you toward help before things become unmanageable.

If you suspect someone else is stealing energy, you can report it 100% anonymously to Stay Energy Safe by filling in the simple online form or by calling 0800 023 2777.