Hi,

I've trawled through lots of posts on the forum regarding SAP assessment procedures and thermal dynamic modelling packages but there seems to be no mention of the BREDEM methodology.

I'm looking at ways to model baseline performance of exisiting housing stock beyond the capabilities of rdSAP. I'm not convinced that complex modelling packages are necessary but recognise that elements such as location, exposure, orientation, occupancy, heating patterns, lighting and appliance use etc assumed by rdSAP are critical variables.

The BRE Domestic Energy Model (BREDEM-12) seems to be the logical methodology to use. Do BRE share this? Has anyone had a go at putting the calculation in to spreadsheet?

Luke

Probelm with identifying air leakage and thermal bypass in exisiting properties is that it entails airtightness testing and thermography - both of which aren't cheap and simple enough to do to every single home.

I'd imagine they would have to remain assumed. Surely we can do this with reasonable accuracy based on property type, construction and floor area? Once insulation is properly installed (properly being the key!)externally or internally a certain percentage improvement could be modelled..

Luke said "Probelm with identifying air leakage and thermal bypass in exisiting properties..... " well, yea, but these losses can be the biggest and are very variable even within house types

I do not think anything can be assumed except that real world energy losses are far bigger than theoretical ones.