News 23.7.2021

Global warming increases hot weather and the risk of housing becoming overheated

In Finland, the room temperatures of dwellings may exceed the limits for buildings laid down in regulations even during the current climate’s hot summers.
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In the future, hotter summers are expected to become more common, at which point we may not only need to sun shields and window ventilation, but also active cooling systems to avoid the overheating of dwellings.

Current building regulations stipulate that the room temperature of new residential buildings should not exceed a limit value of 27°C by more than 150 degree hours per year. In other words, exceeding the limit value by 1 degree is allowed for a maximum of 150 hours, but only 75 hours when exceeding the limit value by 2 degrees. However, during a prolonged heat wave already in the current climate, the number of hours during which 27 degrees is exceeded may be manifold this, and the risk of overheating of dwellings in the future will continue to increase.

More information:

Aalto University, Senior Researcher Juha Jokisalo,, 050 407 2287 Aalto University, Professor Risto Kosonen,, 040 502 7484 Finnish Meteorological Institute, Adjunct Professor Kirsti Jylhä,, 050 433 6554 Finnish Meteorological Institute, Researcher Natalia Korhonen,, 050 919 5454

Azin Velashjerdi Farahani, Juha Jokisalo, Natalia Korhonen, Kirsti Jylhä, Kimmo Ruosteenoja, and Risto Kosonen: Overheating Risk and Energy Demand of Nordic Old and New Apartment Buildings during Average and Extreme Weather Conditions under a Changing Climate. Applied Sciences, 2021, 11, 3972.

Scientific article available here:

Science newsHeat spellClimate changeGlobal warmingOverheating of buildings