Do Air Con Units Use a Lot of Electricity in the UK?

Many UK homeowners hesitate before installing air conditioning because they worry the electricity consumption will be high. With energy bills already a concern, this is an important question. The reality is that modern air conditioning units are far more energy efficient than most people realise, particularly compared to other household appliances and older heating systems.

How Air Conditioning Uses Electricity

Air conditioning units consume electricity to:

• Power the compressor, which circulates refrigerant.
• Operate fans to move air across coils.
• Run electronics and controls.

The efficiency of this process is measured by Seasonal Energy Efficiency Ratio (SEER) for cooling and Seasonal Coefficient of Performance (SCOP) for heating. A higher rating means more output for less input.

Modern systems use inverter technology, which allows the compressor to adjust speed based on demand. This avoids the constant on/off cycling of older models, lowering electricity use significantly.

Typical Power Consumption

Here’s a breakdown of common residential units used in Hampshire, Berkshire, Surrey, and Oxfordshire:

• 2.5 kW bedroom split system: Uses around 0.6–0.8 kW per hour.
• 5 kW living room unit: Uses around 1.4–1.6 kW per hour.
• 7 kW kitchen diner unit: Uses around 2.0–2.4 kW per hour.

At today’s UK electricity tariff of 28p per kWh (Ofgem, 2025), this equates to:

• Bedroom unit: 17p–22p per hour
• Living room unit: 39p–45p per hour
• Kitchen diner unit: 56p–67p per hour

Because systems rarely run at maximum output for long periods, real-world costs are often 30–40 percent lower than the above figures.

How This Compares to Other Appliances

To put this into perspective:

• Electric oven: 2.0–2.5 kW per hour (56p–70p)
• Tumble dryer: 3.0 kW per cycle (£1.40)
• Kettle: 3.0 kW (costing about 2p per boil)
• Dishwasher: 1.5 kW per cycle (70p)

A 5 kW living room air conditioning unit costs less to run per hour than many common appliances.

Seasonal Use in the UK

Unlike countries with year-round reliance, homeowners in towns such as Guildford, Oxford, or Basingstoke generally use air conditioning in the summer and occasionally in spring and autumn. This limited usage keeps annual electricity consumption low.

For example, running a bedroom unit for 8 hours per night over the three hottest months of the year would cost about £120 for the season.

Air Conditioning as Heating

In heating mode, air conditioning works as a heat pump, often outperforming other electric heating options. With a COP of 4, a system can deliver 4 kWh of heat for every 1 kWh of electricity consumed.

Compared to electric panel heaters at 1:1, this is a major saving. For homeowners in Winchester or Reading using air conditioning for targeted heating, electricity use is lower than many alternatives.

Misconceptions About Electricity Use

There are several reasons people assume air conditioning consumes a lot of power:

• Older units did use more energy, but technology has advanced significantly.
• People assume continuous 24/7 operation, which is rare in the UK.
• Some confuse peak power capacity (e.g., 7 kW) with actual electricity use (around 2.2 kW).

Practical Tips to Reduce Electricity Consumption

• Keep systems serviced and filters clean.
• Set temperatures to 21–22°C rather than extreme levels.
• Use zoning so you only condition occupied rooms.
• Combine with blinds or shading to reduce solar gain.
• Choose a reputable installer like ClimateWorks to size and specify units correctly.

The Verdict

Air conditioning units do not use a lot of electricity in the UK when compared with the comfort and efficiency they provide. In fact, for targeted heating and cooling in well-insulated properties across Hampshire, Berkshire, Surrey, and Oxfordshire, they are often one of the most economical and flexible options available.

References

• Ofgem, Energy Price Data 2025 – Ofgem
• Energy Saving Trust, Household Energy Consumption – Energy Saving Trust
• Mitsubishi Electric UK, Air Conditioning Efficiency – Mitsubishi Electric

About the Author

Dr. Julian Carter – Technical & Compliance Director, ClimateWorks

Dr. Julian Carter is a recognised specialist in building services engineering with over 25 years of experience in ventilation, refrigeration, and air conditioning. As Technical & Compliance Director at ClimateWorks, he advises on best practice for system design, installation, and maintenance across residential and commercial projects in Hampshire, Berkshire, Surrey, and Oxfordshire. He also lectures part-time at a leading UK university, sharing his expertise with the next generation of engineers.

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