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U-values by construction period

Here are typical values to start from when the drawings are missing. They are first guesses, not measurements. What matters most is whether the house was built before or after Svensk Byggnorm 1975, which tightened the insulation rules.

Rohi Perlsteyn, KronwattPublished Updated

In brief

  • The U-value shows how much heat leaks out through one part of the house. The lower, the better.
  • The construction year says a lot. Houses built after the mid-1970s are far better insulated than older ones.
  • Windows differ most: old windows let out up to six times as much heat as new ones.
  • The values here are typical, not measured. Replace them when you know more about the house.
On this page
  1. Typical U-values, W/m²K
  2. Windows by glazing type
  3. What is actually in the wall
  4. What added insulation realistically delivers

Svensk Byggnorm 1975 was a response to the oil crisis and raised insulation requirements sharply. A house built in 1974 and one built in 1977 differ more in their envelope than 1977 and 1990 do. If the construction year is all you know, that is still a good deal.

Typical U-values, W/m²K

Element Pre-1960 1960–1975 1976–1990 1991–2010 Post-2010
Walls0,50–0,700,35–0,500,25–0,350,18–0,250,12–0,18
Roof0,50–0,900,30–0,400,15–0,250,12–0,180,08–0,13
Ground floor0,50–1,000,40–0,600,30–0,400,20–0,300,12–0,15
Windows3,50–4,502,00–2,801,80–2,001,20–1,800,70–1,20
Doors2,00–3,001,50–2,501,20–2,001,00–1,500,70–1,00
 Windows span a factor of six between oldest and newest — which is why they often dominate the picture in an old house despite covering little of the area.

Windows by glazing type

If you can see the glazing, this table beats the construction year — windows are often replaced while nothing else changes.

Type Typical era U-value
Single glazingpre-1900s4,5+
Coupled double windows1900–19602,8–3,5
Sealed double glazing1960–19802,0–2,5
Early insulated glass1980-s1,8–2,0
Triple glazing1990–0,9–1,2
High-performance triple2010–0,7–0,9

What is actually in the wall

  • Pre-1940. Log or plank, 10–20 cm sawdust fill, no vapour barrier, natural ventilation.
  • 1940–1960. Transition to mineral wool from the mid-1950s. 50–100 mm sawdust or early mineral wool. Oil boilers appear.
  • 1960–1975. 100–150 mm mineral wool, poorly insulated ground slabs. Oil gives way to direct electric heating. The most common house type in Sweden. Moisture in roughly a third of early-1970s houses; radon and asbestos worth checking.
  • 1976–1990. SBN 75 takes hold: 150–200 mm mineral wool, better airtightness, mechanical exhaust ventilation. Tight houses with weak ventilation bring the first indoor-environment problems.
  • 1991–2010. 200–250 mm walls, 300 mm and more in the attic. Heat pumps become common, heat-recovery ventilation in better-specified houses.
  • Post-2010. 250–350 mm walls, 400–500 mm roof, high airtightness and heat-recovery ventilation as standard.

What added insulation realistically delivers

Measure Cost Share of heating Disruption
Attic floor 300–600 kr/m²10–15 % Minimal, 1–2 days
Window replacement 10 000–14 000 kr/ea~14 % Moderate
Wall insulation 1 600–3 000 kr/m²13–25 % High, 4–10 weeks
Ground floor 300–1 000 kr/m²5–10 % Low to very high
Door replacement 10 000–46 000 kr/ea1–2 % Low
The shares refer to the building's heating demand, not its total energy use.

Sources and caveats

Sources and caveats. Compiled from Kronwatt's own research note on insulation and heating, which in turn draws on Svensk Byggnorm 1975, Boverket's building regulations, Sveby Brukarindata bostäder and the industry's published cost material. The ranges are wide because reality is. The costs are price levels, not quotations, and vary with region, access and contractor.