The increased use of home cooling units in Finland has at least partially prompted an uptick in electricity use during the recent heatwave, according to national grid operator Fingrid.
"When it's very hot, as it was this week, electricity consumption rises. Normally, power consumption decreases as it gets warmer, but in such severe heat it began to increase," Fingrid unit manager Jonne Jäppinen said.
Electricity use starts to rise when temperatures exceed 22 degrees Celsius, and increases as it gets warmer, Jäppinen explained.
"Electricity consumption varies a lot, depending on the time of day, whether it's summer or winter, but there is an additional load of three percentage points when temperatures get closer to 30 degrees," he said.
Part of the reason for the power usage uptick, according to Jäppinen, is that air source heat pumps are increasingly being installed and used in households across the country.
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Air source heat pumps (ASHP) can be used to cool or heat indoor areas more efficiently than traditional air conditioning systems or furnaces, but are generally more efficient when heating.
The units cool air by moving heat from inside a house to the outdoors, rather than pumping in generated cool air, like air conditioners do.
Around 800,000 ASHP units have been installed in homes in Finland, and their numbers continue to grow at a pace of about 80,000 per year. There are also models made exclusively for cooling purposes, which are being purchased at a rate of about 5,000 units per year.
The cooling units are becoming increasingly popular, according to Pekka Malkki, from ASHP installation firm Vantaan ilmalämpö.
"A lot of pumps are being installed in multi-storey and terraced houses these days which are purely cooling units. [Those homes] are usually on district heat and do not require additional heating. Now, in hot weather, the focus is almost exclusively on installing cooling equipment, and they're being put in homes across Finland as quickly as installers are able to," Malkki explained.
However, compared to warmer climates, Finland's energy requirements for cooling are relatively low. Per-household cooling costs in the country amount to about one euro for each day with temperatures above 25 degrees.