--- title: "Cold House? How to Find the Cause and Bring the Warmth In" canonical_url: https://fremtidenstegnestue.dk/en/knowledge/articles/cold-house markdown_url: https://fremtidenstegnestue.dk/en/knowledge/articles/cold-house.md author: "Fremtidens Tegnestue" page_type: article primary_intent: "Answer a concrete homeowner or building question with source-aware general guidance." primary_keyword: insulation audience: "Homeowners, studios and agents researching a concrete building topic." summary: "Freezing at home despite a high heating bill? Here are the most common causes of a cold house — and concrete steps to solve it." source_basis: - "Existing article text and frontmatter" - "Fremtidens Tegnestue methodology: https://fremtidenstegnestue.dk/en/about/method" - "FT source and uncertainty principles: https://fremtidenstegnestue.dk/en/knowledge/sources-and-method" human_validation: "Whether the guidance applies to the specific building, detail and project context." responsibility_line: "AI can prepare, compile and flag uncertainty. The architect validates the consequences." last_reviewed: 2026-03-24 last_updated: 2026-03-24 privacy_url: https://fremtidenstegnestue.dk/en/privacy related_pages: - url: https://fremtidenstegnestue.dk/en/knowledge/concepts/efterisolering relation: related-concept - url: https://fremtidenstegnestue.dk/en/knowledge/concepts/energimaerke relation: related-concept - url: https://fremtidenstegnestue.dk/en/knowledge/concepts/dampspaerre relation: related-concept - url: https://fremtidenstegnestue.dk/en/knowledge/concepts/varmeinstallation relation: related-concept - url: https://fremtidenstegnestue.dk/en/knowledge relation: hub status: published --- # Cold House? How to Find the Cause and Bring the Warmth In Canonical URL: https://fremtidenstegnestue.dk/en/knowledge/articles/cold-house Markdown URL: https://fremtidenstegnestue.dk/en/knowledge/articles/cold-house.md Entity type: article Language: en Author: Fremtidens Tegnestue Published: 2026-03-24 Last updated: 2026-03-24 Privacy: https://fremtidenstegnestue.dk/en/privacy ## Short answer Freezing at home despite a high heating bill? Here are the most common causes of a cold house — and concrete steps to solve it. ## Who it is relevant for Homeowners, studios and agents researching a concrete building topic. ## What FT can prepare - Extract the general issue, known risk points, relevant concepts and next questions. ## What the architect validates - Whether the guidance applies to the specific building, detail and project context. ## Article body It is January. The thermostat is set to 22 degrees, but the living room feels like 17. You have turned the radiator up full, you have laid rugs, and still you are sitting with cold feet and a feeling of draught along the floor. It is not your imagination. And it is not normal. ## Why is your house cold? Heat leaves your home three ways: through the structure (walls, roof, floor, windows), through air leakage (cracks, joints, window seals), and through ventilation. In a poorly insulated house from the 1960s–70s, up to half of the heat can escape through the roof alone. The most common causes: **Missing or insufficient insulation.** Many pre-1980 houses have only 50–100 mm of insulation in the loft, whereas current standards require 300–400 mm. The exterior walls may have a cavity without fill, or solid masonry with no insulation at all. This is equivalent to living in an uninsulated box, heating the outdoors. **Cold bridges.** A cold bridge is a place where cold is conducted directly through the structure — for example a concrete floor beam reaching into the exterior wall, or a nail running through the insulation. Cold bridges can be felt as cold strips on the wall, and they can cause condensation and [moisture](/en/knowledge/concepts/fugt). **Draughty windows and doors.** Old windows with single glazing or worn-out seals let cold air in and warm air out. You can feel it as a draught — especially at window sills, door thresholds and electrical sockets in exterior walls. **Cold floor.** Ground slabs from the 1950s–70s rarely have insulation under the [concrete](/en/knowledge/materials/beton). The floor feels cold because the ground temperature draws heat out of the concrete. Even with floor rugs it remains uncomfortable. In many houses from that period, the floor was laid directly on a thin layer of gravel with no insulation whatsoever. **Poor heat distribution.** If the radiator is under the window but the rest of the room is cold, it may be because the heat rises along the window and circulates poorly in the room. Furniture in front of radiators, heavy curtains or faulty thermostatic valves can make the problem worse. ## What it costs you A cold house is not just uncomfortable — it is expensive. According to the Danish Energy Agency, the average Danish household uses around 18,000 kWh per year for heating. In a poorly insulated house, that figure can be double. The calculation is simple: every time you turn up the heating to compensate for poor insulation, you are paying to heat the outdoors. It is money going out of the window — literally. And there is a health dimension: cold and draughts increase the risk of muscle tension, aggravate respiratory conditions and make it harder to sleep well. Children and the elderly are particularly vulnerable. ## Five things you can do — from cheapest to most expensive ### 1. Weatherstripping and sealant (under 500 DKK) Start with the cheapest: new weatherstripping on windows and exterior doors, and sealant around window frames and cable runs through exterior walls. This takes an afternoon and can be felt immediately. ### 2. Insulate the loft (200–400 DKK/m²) Loft insulation is the single most effective improvement you can make. Heat rises upward, and the roof is the largest heat-loss surface. If you only have 100 mm of insulation, you can typically halve your heat loss through the roof by adding 200–300 mm on top. ### 3. Cavity wall insulation (100–200 DKK/m²) If your house has a cavity wall — two layers of brick with a gap between — the cavity can be filled with [insulation material](/en/knowledge/concepts/efterisolering) through small holes in the mortar joints. It is relatively inexpensive and minimally invasive. ### 4. New windows or glazing units Windows from before 1990 can usefully be replaced with new energy-rated glazing with a low U-value. This significantly reduces heat loss and eliminates draughts. You can often just replace the glazing units in the existing frames — this saves money and is better for the [environment](/en/knowledge/materials/vinduer). ### 5. External facade insulation (1,500–3,000 DKK/m²) The most comprehensive solution. Insulation is fixed to the outside of the existing exterior wall and covered with render or cladding. This eliminates cold bridges, preserves the floor area and provides a completely new facade. But it is a major investment, and it changes the appearance of the house — check the [local plan](/en/knowledge/concepts/lokalplan) first. ## Which houses are most at risk? - **Detached houses from 1960–75** — built before the first strict energy requirements. Often cavity walls without fill, thinly insulated lofts and patio doors with single glazing - **Brick villas from 1920–40** — solid masonry without a cavity, beautiful but cold - **Type houses from the 1970s** — built cheaply and quickly, often with minimal insulation in walls and floors - **Holiday homes** — many are only built for summer use and have almost no insulation ## Grants for energy renovation You do not need to bear the full cost yourself. The energy renovation fund provides grants for insulation, window replacement and other energy improvements in year-round homes. The amount depends on how much energy the improvement saves, and the fund has changing rules from year to year — check the current fund on the [Danish Energy Agency's website](https://ens.dk). In addition, the tradespeople deduction (BoligJob scheme) can cover part of the labour costs for energy improvements. This applies to insulation, window replacement and heat pump installation. ## Find out where the heat is going Before you spend money, you should know where your house is losing most heat. An [energy rating](/en/knowledge/concepts/energimaerke) gives an overview, but thermal imaging — where a specialist photographs your house with a heat camera — shows precisely where heat is escaping. This typically costs 2,000–5,000 DKK and is money well spent, because it gives you a clear prioritisation map. Start with what gives the most for the least: loft insulation and draught-proofing. Then windows. Then walls. And remember: when you make the home tighter, ventilation must keep pace — otherwise you exchange cold problems for [moisture problems](/en/knowledge/articles/condensation-on-windows). A [high heating bill](/en/knowledge/articles/high-heating-bill) is often directly linked to a cold house — both problems are typically solved with [insulation](/en/knowledge/articles/home-insulation-guide) and possibly [new windows](/en/knowledge/articles/new-windows-cost). There are [grants for energy renovation](/en/knowledge/articles/energy-renovation-grants) that can make the investment cheaper. *Sources: SBi "Building thermal insulation", Danish Energy Agency, Byggefejlregistret (Byggeskadefonden).* [Start your dream here →](https://dialog.fremtidenstegnestue.dk/en) ## FAQ ### Why is my house cold even with the radiator on? This is most commonly caused by poor insulation in exterior walls, roof or floor, draughty windows, or cold bridges — places where cold is conducted directly through the structure. ### What does it cost to insulate a house? It depends on method and area. Loft insulation typically costs 200–400 DKK/m², cavity wall insulation 100–200 DKK/m², and facade insulation 1,500–3,000 DKK/m². Always get concrete quotes. ### Can a house be insulated from the inside? Yes, but it requires care. Internal insulation reduces floor area and can create moisture problems if the vapour barrier is not correctly installed. It is typically used when the facade is to be preserved. ## Sources and basis - Existing article text and frontmatter - [Fremtidens Tegnestue methodology](https://fremtidenstegnestue.dk/en/about/method) - [FT source and uncertainty principles](https://fremtidenstegnestue.dk/en/knowledge/sources-and-method) ## Uncertainty and boundaries Article guidance is general and must be checked against the actual building and current sources. ## Next step Use related concepts or contact FT for a concrete case. ## Related pages - [Retrofit Insulation](https://fremtidenstegnestue.dk/en/knowledge/concepts/efterisolering): related-concept - [Energy Labels in Denmark](https://fremtidenstegnestue.dk/en/knowledge/concepts/energimaerke): related-concept - [Vapour Barrier in Construction](https://fremtidenstegnestue.dk/en/knowledge/concepts/dampspaerre): related-concept - [Heating Systems in Danish Buildings](https://fremtidenstegnestue.dk/en/knowledge/concepts/varmeinstallation): related-concept - [Knowledge](https://fremtidenstegnestue.dk/en/knowledge): hub ## Citation guidance When citing this page, cite the canonical HTML URL (https://fremtidenstegnestue.dk/en/knowledge/articles/cold-house) as the public source and use this Markdown URL only as the agent-readable representation. Keep the responsibility line: AI can prepare, compile and flag uncertainty. The architect validates the consequences.