You will hear a lot of talk and read a lot of comment on the importance of U values when it comes to house insulation from both manufacturers and installers. In addition there is a whole section of the Building Regulations – Part L – devoted to enforcing certain U value standards throughout the structure of a house and covering the roof,walls,windows and floor areas.
Basically a U value is a measurement of the thermal efficiency of a material or collection of materials and represents how much heat is lost from the inside of a building . The lower the figure the better and also the slower the heat loss.
As some kind of yard stick a new build house has to hit a 0.25 U value overall and an existing solid 9 inch wall on a 1930′s house is rated at 2.05 U value !!
External thermal insulation systems on solid wall properties will typically reduce the heat loss through the walls by around 75% minimum with a resultant significant reduction in heating bills and carbon emissions as well.
For retro fitting to houses with no cavities the Building Regs give a target of 0.3 U value if possible with a maximum figure of 0.7 allowed.
2 Responses to Thermal Insulation U values explained
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British Board of Agrement
Consumer Direct
Energy Saving Trust
Federation of Master Builders
Guild of Master Craftsmen
THINC™ Wethertex™
I thought they started cavity walls in the 1920′s? I have a 1924 semi that has cavity wall construction and we have since had the cavity insulation injection filled, so it should be a bit better than 2.05 hopefully. Our previous house was indeed 9″ brickwork (victorian) and that was freezing….
Hi
Yes there were some early cavity properties but these were not part of the mainstream build until the 1930′s and indeed I know of a 1903 property nr Gosport that also has a decent sized cavity.
Interesting to hear your comments on the difference that insulation has made to your current home versus your old solid wall home.