U Value Calculations for new and existing buildings

April was a quieter month for us, mostly because of Easter and all those Bank Holidays! One thing that has kept us busy though is doing U value calculations.

We are currently working with Green Deal Providers and cavity wall insulation installers to undertake before and after U value calculations for ECO, Green Deal and other retrofit installations.

Using SAP software Up Energy can calculate the U value improvement to the wall to be cavity-filled or to be internally or externally insulated. Based on the information provided by the installer or assessor we supply a ‘before and after’ SAP/U value calculation that any DEA (Domestic Energy Assessor) can input into their Energy Performance Certificate (EPC).

The more common reason we carry out calculations to assess U values is for new build projects, both domestic and non-domestic construction.  Depending on the software used, as well as calculating the thermal conductivity, we can also calculate the thermal mass of the element.  The output from these calculations then goes directly in to the model to help determine the heat losses from the building.

The thermal mass value is then based on the first 100mm of construction layers, from inside to outside.  Thermal mass is the ability of a material to absorb and store heat energy.  A high thermal mass construction would be something like dense concrete and low thermal mass would be a material such as timber, or plasterboard.  As soon as the insulation layer is reached, that is the extent of the layers that make up the thermal mass.  Used correctly, thermal mass can help reduce overheating in buildings in summer and also smooth out the heating cycle in winter.

As fully qualified OCDEA and SAP assessors, we can carry out U value calculations for any building in England and Wales and send you back the documents you require.  Get in touch if you and we will be happy to help.