Glossary

BRE
The Building Research Establishment, based in Watford. 

BRE Website link
“The BRE Trust is a charitable company whose objectives are through research and education, to advance knowledge, innovation and communication in all matters concerning the built environment for public benefit.”

TRV
Thermostatic Radiator Valves – fitted to wet central heating radiators to allow the temperature to be reduced in individual rooms.

 

U value
A figure describing the rate at which given building materials, walls, doors etc, loose heat. The value is expressed in watts/m2/oC. That is, energy lost per square metre of surface per degree Centigrade.

 

R value
A figure desribing, for a given material, the resistivity of that material to trasnmitting heat. It is the opposite of the ‘U’ value in mathematical terms. The value is expressed in m2oK/W. That is the number of square metres of the material needed to trsnmit one Watt when the temerature difference is one degree Kelvin (or Centigrade).

 

Converting from R to U
To convert from R to U take the material thickness in metres and divide by the R value. So, 60mm of insulation at R = 2.727 gives a U value of 0.022