15 May is Denmark’s national summer shut-down date for heating systems. By turning off the heating during the summer months, you save money while also reducing the building’s climate footprint.
The date 15 May is used as a guideline by the Danish Energy Agency and energy companies, as the need for heating typically decreases significantly around mid-May. It is not a legal requirement, but a helpful reminder to switch the heating system to summer operation.
What does summer shut-down mean?
When you turn off the heating system during the summer months, you do not turn off the hot water supply. Only the part of the system that provides heat to radiators, underfloor heating and other forms of space heating are switched off. This prevents the system from using energy for heating that is not needed.
The Danish Energy Agency has published a number of simple guides on how to shut down heating systems. There are guides covering district heating, heat pumps, natural gas, oil-fired boilers and pellet stoves.
Is it worth shutting down the heating for the summer?
The short answer is: Yes.
According to the Danish Energy Agency’s website SparEnergi, you can save 2–3% of your annual heating consumption by turning off the heating system from May to October. This corresponds to an indicative saving of approximately DKK 250–450 and around 40–42 kg of CO₂ per year for an average 85 m² apartment with district heating.
The example is intended as an indicator only. Your actual savings depend on the size of the home or building, energy prices and the type of heating system used.