Very warm days are becoming increasingly common during the British summer, so you may be wondering about getting some form of air conditioning (AC).
Nevertheless, this is an energy-intensive process, so it’s natural to wonder how much it will cost you before making a decision. There’s no simple answer, but here are some factors that affect this cost, as well as some tips to reduce it.
Some factors that influence the cost of air conditioning
The cost of electricity
AC consumes electricity, so the price you pay for electricity is directly related to how much it costs to run AC. Really warm days also tend to be sunny too, though, so if you have solar panels fitted, you may be able to run your AC without consuming power from the grid.
The form of air conditioning
There are three basic forms of AC units: portable, split and ducted. Portable units are the easiest to install because they expel hot air through an exhaust hose to an open window. They are reasonably efficient and flexible because they can be moved from room to room and put away when not needed, but they may be unsuitable for very large spaces. Split systems have units inside and outside the home, so they require permanent installation, but their running costs can be lower than portable units.
Ducted systems are mostly only seen in commercial spaces in the UK. A single large air conditioning unit drives hot or cold air through a network of ducts, so they are more complicated to install and maintain, but they can be more efficient for very large spaces.
Target temperature
Setting a more ambitious target temperature on the thermostat means the AC unit needs to work harder to reach and maintain that temperature.
The power and efficiency of the unit
To give an illustrative example, if you pay 25p per unit (kilowatt-hour) for electricity, it will cost 50p to run a 2 KW AC unit at full power for an hour. The reality is more nuanced, however, because the unit may operate at a lower power level if conditions allow, meaning less electricity consumption and a lower cost. Very efficient AC units (e.g. those rated A++ or better) will also use less power to achieve the same results.
Home insulation
Insulation doesn’t just keep heat in your house—it can also help keep it out. With less heat getting into your home, your AC needs to work less, meaning it uses less electricity and therefore costs less to keep you comfortable.
How much you use it
Obviously the longer it’s on, the more energy an AC unit uses, even if the temperature would be tolerable without it.
Tips for lowering the cost of air conditioning
Programme the thermostat
If you get AC with a programmable thermostat, you can schedule it to turn on and off at convenient times. For example, it could be off during the day but come on automatically about an hour before people start returning home, so the house will be nice and comfortable for them.
Keep sunlight out during the day
Closing blinds and curtains during the day can help prevent sunlight from heating your home up further during the daytime. In contrast, if it gets cooler in the evening, it may be worth turning off your AC and opening some windows instead to let the house cool naturally.
Use extra fans to circulate air
Running ventilation fans can help move the cool air around and take some pressure off the AC unit.
Upgrade your insulation
If your insulation is inadequate, upgrading it can relieve some of the load off your AC by keeping more heat out. It will also help with the energy bills in winter by keeping more heat inside.
Make sure air filters are clean
Your AC unit will need to work harder if its air filters start restricting airflow, so it’s important to clean them regularly and replace them when needed.
Choose a more efficient unit
Opting for a more efficient (e.g. A++ rated) unit will save on your running costs in the long term.
Depending on the above factors, expect to pay something like 20p to £1.20 per hour to run an AC system at the current July 2025 Ofgem cap of 25.73p per unit. Split systems are generally considered the most efficient option for homes and small business spaces but incur a greater upfront cost due to the installation. Xgas can provide an installation while helping to spread this cost, though, so get in touch today to learn about financing options.