How much does it cost to cool a home with an air conditioner?

An air conditioner's running costs vary depending on its efficiency, the price of electricity, the size of your home, where the indoor unit is placed, and the climate. On average, cooling an apartment, say a two- or three-room flat, costs around €20–40 a year, depending mainly on the price of electricity and the number of hot days. In larger homes, the price can run €40–50 a year. By investing in an efficient unit and using it sensibly, you can enjoy a cool home without an unreasonable electricity bill.

What determines the cost of cooling?

1. Electricity use and efficiency

An air conditioner's energy efficiency is measured using SEER (Seasonal Energy Efficiency Ratio) and EER (Energy Efficiency Ratio) ratings. The higher the SEER, the less electricity it uses. New air conditioners typically have SEER ratings between 6 and 12, and a higher number means a smaller electricity bill.

2. The price of electricity

Cooling costs depend entirely on the local price of electricity, measured in kilowatt-hours (kWh). In Finland, the price of electricity varies, but averages around €0.15–0.30/kWh. The cost is calculated by multiplying the unit's consumption by the price of electricity.

3. Home size and insulation

A larger home needs more cooling capacity. A typical 3.5 kW air conditioner uses 600–1,200 watts an hour, depending on the model and output. Good insulation, energy-efficient windows, and draught-proofing all reduce how much cooling you need, and therefore your electricity bill too. In apartment buildings, it's worth making sure the balcony glazing is open so the hot air blown out by the outdoor unit can actually escape.

4. Local climate

If you live in the south, the unit may run all summer, while in the north its use might be limited to just the hottest days. The more cooling you need, the higher the costs.

5. Where the unit is placed

Optimal placement of the indoor unit reduces how much runtime you need. When cool air can circulate through the home more effectively, you reach the temperature you want faster.

What does cooling actually cost?

For example:

• A 3.5 kW air conditioner with a SEER of 7 uses around 800 watts (0.8 kWh) an hour.
• If it runs 8 hours a day, that's 6.4 kWh a day.
• At an electricity price of €0.15/kWh, that's €0.96 a day.
• Finland averages around 40 hot days a year, so the annual cost would be around €38.40.

In larger homes the cost goes up, but choosing an efficient unit and using it wisely can save you a significant amount. In houses with solar panels, cooling can be effectively free, since the need for sunlight and the need for cooling tend to line up.