HERTFORDSHIRE, BEDFORDSHIRE & CAMBRIDGESHIRE
Air Conditioning Running Costs
What a wall-mounted unit really costs to run per hour, per day and per season at the current price cap rate, how heating a room with it compares with gas, and which type of system suits your home. Work it out below, then get a fixed price for the installation in about two minutes.
Running cost estimator
What will it cost to run?
Pick how many rooms you will be cooling or heating, how long for, and your electricity rate. The figures update as you go.
At a glance
What air conditioning costs per hour
A season is 60 days of cooling or 90 days of heating, six hours a day. Every figure is the running average for a modern inverter unit, which slows right down once the room is at temperature rather than running flat out.
| At 26.32p per kWh | Per hour | Six hours a day | A season |
|---|---|---|---|
| Cooling one room | 11p | 63p | £37.90 |
| Cooling two rooms (multi-split, both on) | 21p | £1.26 | £75.80 |
| Heating one room with the same unit | 17p | £1.03 | £92.38 |
| A 2 kW electric fan heater, for comparison | 53p | £3.16 | £284.26 |
| A portable air conditioner, for comparison | 26p | £1.58 | £94.75 |
The fan heater line is the one to remember. The same unit that cools a bedroom in July heats it in January for about a third of what a plug-in heater costs, because it moves heat from outside rather than making it from scratch.
Heating
Cheaper than gas for one room
Every unit we fit is a heat pump as well as a cooler. Per kWh of heat delivered to the room, it beats the gas boiler at current prices. The honest caveat is that the boiler heats the whole house from one place, and the air conditioner heats the room it is in.
| Cost of one kWh of heat in the room | Pence | How |
|---|---|---|
| Air conditioning in heating mode | about 6.6p | 26.32p of electricity makes roughly 4 kWh of heat (a seasonal efficiency, SCOP, of about 4) |
| Gas central heating | about 8.9p | 7.97p per kWh of gas at about 90% boiler efficiency, before the standing charge |
| Electric fan or panel heater | 26.3p | One kWh in, one kWh out |
Where it makes sense: a home office, a loft room or a conservatory that the radiators never quite reach, the spare bedroom you only heat when someone stays, and the months either side of winter when firing the whole boiler for one warm room is a waste. On the coldest mornings the efficiency drops towards 2.5 to 3, so the gap narrows, but it stays cheaper than any plug-in heater.
Which system
Single split, multi-split or ducted
Three ways to do it, and the right one depends on how many rooms, how the house is laid out and where the outdoor unit can go. The survey settles it; this is the short version.
One room
Single split
- Cools and heats one room
- About 11p an hour to cool, 17p to heat
- Fitted in a day
- 0% VAT on most residential installations
Best for: a bedroom, a home office, a lounge or a conservatory.
Two to five rooms
Multi-split
- One outdoor unit for the whole house
- Running cost rises with each room switched on, not with the size of the outdoor unit
- Usually fitted in one to two days
- Neater than two or three separate outdoor units
Best for: bedrooms plus a living room, or a whole floor of a house.
Whole floor, office, shop
Ducted and ceiling cassette
- Nothing on the walls
- Sized for offices, shops, surgeries and large open-plan rooms
- Higher install cost, needs ceiling access
- Serviced under a maintenance plan
Best for: commercial premises and large open-plan homes.
Sizing, roughly: a 2.5 kW unit suits a room up to about 25 square metres, 3.5 kW up to about 35, and 5 kW up to about 50, with a bigger unit for south-facing glass, lofts and open-plan kitchens. An undersized unit runs flat out and costs more per hour than a correctly sized one idling.
Fitted right first time, F-Gas certified
Survey, supply, installation and commissioning by our own engineers, with the trunking run properly and the manufacturer warranty registered for you. A 12 month guarantee on our labour.
★★★★★
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Why choose Vantage
Rated 4.9 on Google from more than 700 reviews across Google, Checkatrade and Trustatrader. Qualified, accredited engineers, a fixed price before any work begins and a labour guarantee on every job, from an established local company with an office team you can actually reach. No job too small.
Gas Safe registered
Company registration 956889. Every gas engineer carries their own Gas Safe ID card, and you can ask to see it.
Refcom F-Gas certified
REF1024550. Legally required for air conditioning installation and servicing, and we hold it.
CHAS Elite accredited
Veriforce CHAS assessed for health and safety, which is why commercial clients and landlords use us.
City & Guilds and BPEC qualified
Qualified, insured engineers on every job. No subcontracted strangers.
700+ reviews, 4.9 on Google
Across Google, Checkatrade and Trustatrader. Read them before you book.
Labour guarantee on every job
12 months on repairs, installations and everything else. Two years on a full bathroom refit. If anything we did develops a fault, we come back and put it right.
Fixed price before we start
The price is agreed with you before any work begins. No hidden extras on the invoice.
24/7, answered by a person
The emergency line is answered every day of the year by someone who can send an engineer, not a call centre.
Fully stocked vans
Five vans carrying the parts that fail most often, so most jobs are fixed on the first visit.
An office team behind every job
An established local business with multiple engineers and a dedicated office team to keep you informed.
Vaillant myREWARDS and Ideal Max accredited
Accredited installer status means extended manufacturer warranties on the boilers we fit.
Emergency response within the hour
Our average response to an emergency call is under an hour across Hertfordshire, Bedfordshire and Cambridgeshire.
Trusted & Accredited Professionals
Frequently asked questions
How much does air conditioning cost to run in the UK?
At the October to December 2026 price cap rate of 26.32p per kWh, a typical wall-mounted unit cooling one room costs about 11p an hour, roughly 63p for a six-hour day, and around £37.90 for a 60-day summer. Heating the same room in winter costs about 17p an hour. These are running averages for modern inverter units, which slow down once the room reaches temperature.
Does air conditioning use a lot of electricity?
Less than most people expect. A 2.5 to 3.5 kW wall unit draws about 0.3 to 0.5 kWh per hour of cooling on average, which is less than a kettle boiling for the same time and about half of what a portable air conditioner uses. It uses more on a very hot afternoon and much less in the evening when the room is already cool.
Is it cheaper to heat a room with air conditioning than with gas central heating?
Per kWh of heat in the room, yes at current prices: about 6.6p with air conditioning against about 8.9p with a gas boiler, because a heat pump delivers roughly four units of heat for every unit of electricity. The boiler still heats the whole house from one place, so the saving is real for one or two rooms, not a reason to stop using the boiler in January.
Does a multi-split cost more to run than separate single splits?
For the same rooms at the same settings, about the same. The running cost follows the number of indoor units switched on and how hard each one is working, not the size of the outdoor unit. The multi-split saves on the installation and leaves one outdoor unit on the wall instead of two or three.
Why is there 0% VAT on air conditioning installations?
The units we install are air-to-air heat pumps, which are on the government list of energy-saving materials, so most residential installations are zero-rated for VAT. Commercial installations and some repairs are charged at the standard rate. We confirm which applies on the quote.
What size air conditioning unit do I need?
As a rule of thumb, 2.5 kW for a room up to about 25 square metres, 3.5 kW up to about 35, and 5 kW up to about 50. South-facing glass, lofts, kitchens and open-plan rooms need more. We measure the room and check the glazing and insulation on the survey rather than guessing from the floor area alone.
Prices in the tables use the Ofgem price cap unit rates for 1 October to 31 December 2026. Your own tariff may differ.
Get a fixed price for your air conditioning
Answer a few questions about your home and get an estimated price straight away, no waiting, no sales calls, no obligation. Or book a survey and we will size it properly in person.
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