Is It Cheaper to Run a Fan or Air Con?

When summer arrives in the UK, many households reach for a fan to cool down. Others switch on their air conditioning system. The common question is which option is cheaper to run. The short answer is that fans cost far less per hour, but they do not provide the same benefits as air conditioning. To make the right choice, it is important to look at both cost and comfort.

The Cost of Running a Fan

A typical desk or pedestal fan in the UK uses between 30 and 70 watts of electricity. At the current average tariff of 28p per kWh (Ofgem, 2025), this translates to:

• 30W fan: less than 1p per hour
• 70W fan: about 2p per hour

This is why fans are considered one of the cheapest cooling options available. Running a fan all day might only add 20p to your energy bill.

The Cost of Running Air Conditioning

Air conditioning systems use more energy but provide actual temperature control. A modern inverter-driven 2.5 kW split unit may consume around 0.7 kW of power. At 28p per kWh, the cost is roughly 20p per hour.

A larger 5 kW unit for a family room may consume 1.5 kW, costing about 40p per hour. An open-plan kitchen diner unit of 7 kW capacity may cost closer to 60p per hour.

While this is significantly more than a fan, the difference lies in what you receive for the money.

Comfort and Performance

Fans do not reduce the temperature of a room. They simply move air, which increases the rate of evaporation from your skin and creates a cooling sensation. On very hot nights in towns like Basingstoke or Guildford, this can still feel uncomfortable if the actual room temperature remains high.

Air conditioning lowers the room temperature and reduces humidity. This provides genuine comfort, particularly in bedrooms. A family in Reading might use a bedroom split system overnight for 8 hours, costing £1.60. The benefit of uninterrupted sleep in a cool environment is worth far more than the small daily cost.

Health and Air Quality

Another difference between fans and air conditioning is air quality. Fans only move existing air, potentially circulating dust and allergens. Modern air conditioning systems filter and dehumidify the air. In areas like Winchester or Oxford, where pollen levels are high in summer, this can make a big difference to allergy sufferers.

Comparing Use Cases

• Fans are ideal for short-term relief, small budgets, and homes with good natural ventilation. They are portable, cheap to buy, and extremely inexpensive to run.
• Air conditioning is better for lasting comfort, controlling temperature in loft conversions, garden offices, and open-plan living areas. It also doubles as a heat pump in winter, adding value year-round.

Cost in Context

Running a fan all night might cost less than 10p. Running a small air conditioner overnight might cost £1.60. Over a hot week, the difference could be around £10. For many households in Hampshire, Berkshire, Surrey, and Oxfordshire, this is considered a fair price for comfort.

Compared with other appliances, the cost is still modest. A single tumble dryer cycle costs around £1.40, and an electric oven for two hours can cost 84p. An evening of air-conditioned comfort falls in the same range.

Making the Right Decision

If your home rarely gets hot and you only need occasional relief, a fan may be enough. If you struggle to sleep in hot weather, work from home in an upstairs room, or want all-year benefits including heating, air conditioning is the better choice despite the higher running cost.

Installers like ClimateWorks help homeowners across Basingstoke, Farnham, and Wokingham assess whether a simple fan, a portable unit, or a permanent split system makes the most sense.

References

• Ofgem, Electricity Tariffs 2025 – Ofgem
• Energy Saving Trust, Appliance Running Costs – Energy Saving Trust
• Mitsubishi Electric UK, Residential 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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