Can your sommerhus handle winter?
Most Danish sommerhuse are used ten weekends a year. The ones built for the cold season get thirty or more. Here is what separates them.
Updated June 2026
A sommerhus that closes in October is only half a house. The light in November, the quiet of a frozen coast in February, the first warm weekend in April. These are the moments most owners never get, because the house cannot keep up. A sommerhus used from June to August gives you roughly ten weekends a year. Extend the season through winter and you triple that. Same house, same plot, three times the life lived in it.
One clarification first. Danish planning law allows year-round use of a sommerhus for weekends and holidays, but permanent residence in a sommerhus area is restricted and generally reserved for pensioners who have owned the house for at least a year. This article is about use, not residence.
The common mistake is to think winter capability comes from a bigger heater. It does not. A heat pump in a 1970s cabin with 50 mm of mineral wool in the walls will run constantly, the floors will stay cold, and the electricity bill will explain why. What actually decides whether a house works in winter is the building itself:
- Insulation in walls, roof and floor
- Airtightness of the construction
- Window quality and orientation
- A heating setup that matches how you use the house
Insulation is measured in U-values, and lower is better. Older sommerhus walls often sit around 0.5 to 1.0 W/m²K, while a house built to current standards reaches roughly 0.15 to 0.25. That difference alone can cut heating demand by more than half. The floor matters just as much. Cold floors end winter weekends faster than cold air does, and a properly insulated floor changes how the house feels more than any thermostat setting.
Windows are where most heat leaves. Old double glazing performs around U 2.5 or worse, modern triple glazing reaches 0.8 to 1.0. Good glazing also decides whether you can sit by the window in January without a draft. And orientation works for you: large glass facing south or west collects free solar heat in spring and autumn, exactly the seasons you are trying to win back.
Heating a sommerhus is not like heating a home. It needs two modes: away and arriving. An air-to-air heat pump with app control handles both. Keep the house at 5 to 8 degrees between visits to protect against frost and damp, then start heating from your phone on Friday morning and arrive to 21 degrees that evening. A wood stove belongs in the picture as atmosphere and backup, not as the primary source.
The last piece is moisture, the silent killer of closed-up winter houses. Every weekend of cooking and showering leaves humidity behind, and a cold, sealed house gives it nowhere to go. The result is musty air in spring, or mold behind the panels. Never let the house go fully cold, and make sure air can leave: humidity-controlled extraction in bathroom and kitchen as a minimum, balanced ventilation with heat recovery in a tight, well-built house.
Before you decide anything, run this check on your house, or one you are considering:
- At least 200 mm of insulation in roof and walls
- Insulated floor construction
- Windows newer than 15 years, ideally triple glazed
- Heating controllable from your phone
- Frost protection mode when the house is empty
- Mechanical extraction in bathroom and kitchen
- The house smells neutral after a month closed
Seven checks and the house is ready for winter. Three or fewer, and retrofitting may cost more than the house is worth. That calculation is worth doing honestly before any project begins. A sommerhus that works in all four seasons is not a luxury upgrade. It is the same house, used three times as much.
Need help assessing your plot or advice how to extend use of your summerhouse?
Our certified architect advises on insulation standards, heating setups and building permits across Denmark. Book a consultation and we take it from there.
*General guidance only. Building performance varies by construction, plot and municipality. Always verify before beginning any project.
