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SBEM Calculations

An SBEM or Simplified Building Energy Model, is a Government Defined process in accordance with Building Regulations Part L2a and Part L2b. It is the calculation of the energy performance of new commercial, industrial and or retail buildings. As from 7th April 2007 all new buildings would require an SBEM Calculation.

Thermal Bridging Calculations

Under Part L of the Building Regulations, thermal bridging must be considered in Standard Assessment Procedures (SAP) and Simplified Building Energy Model (SBEM) calculations.

Thermal bridges can account for 20-30% of the heat loss in a typical new build home. As homes become better insulated thermal bridges become even more significant.

Thermal bridging results in heat loss through junctions in the building fabric. The junctions include wall-roof and wall-floor junctions, party walls, corners, cills, jambs, lintels, and any other significant junctions of the building fabric. Their effects are expressed as a linear thermal transmittance value. This is used to arrive at a Y-value: a factor, which allows calculation of the building’s overall heat loss through thermal bridges.

There are a number of accredited or calculated psi values which are available for use within a SAP Calculation from accredited bodies or insulation or building fabric manufacturers.

Accredited Construction Details and associated Psi values for a new build design are available from the Planning Portal web site.

Alternatively, you can have your Psi values calculated by a suitably qualified person in accordance with BR 497 and forward them to us for use in your calculations.


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