Sun, 19 Apr 2026 03:19:07 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215324#Comment_215324 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215324#Comment_215324 Tue, 16 Dec 2014 18:54:47 +0000 revor The house is a stone farmhouse but I made the mistake of externally insulating it to early we should have just done enough to get an EPC at the lower end then get the generous RHI and insulate later. Seemingly had we not externally insulated, the house would have been classed as a pre 1900 house the RHI would then have been very generous, but the Green Deal assessor has told me that the EPC would take into account the external insulation which puts the house in a completely different category.
We have added an extension with wider cavities at double the Building regs requirement. We do not have a SAPS because it is not new build and because we have not finished the build cannot get an EPC and the assessor has stated he cannot do one until the heating system is installed, but at the moment I cannot determine the best system to put in. If I could calculate the Specific Heat Demand ( Kwh/sq.m/year) of the completed house then I can use this in an RHI calculator which would give me a good indication of where to go with it. The company that designed the u/f heating system calculated from the u values I have supplied a heating loading of the system in Kw at -3 deg c ambient. Does anyone know how I can get from this figure to the Specific Heating Demand?
Thanks]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215326#Comment_215326 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215326#Comment_215326 Tue, 16 Dec 2014 19:13:15 +0000 SteamyTea For RHI purpose you need to do this for each room. So you need to know the U-Value of internal walls, doors, floors and ceilings.

Alternatively, if you just want to know how much energy you need to heat the place, get a few fan heaters and a few cheap thermometers. Read your electric meter, take an outside temperature reading, turn the heaters on and when the house is warm enough, say 21°C in the living area and 18°C in the sleeping area, re-read the meter (also take an outside temp reading again). Leave the fan heaters going for a few house to make sure the internal temperatures are stable, then re-read the meter.
You can then work out the the peak power you need to heat the place up and the energy losses needed to keep the temperature there.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215700#Comment_215700 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215700#Comment_215700 Mon, 22 Dec 2014 18:28:44 +0000 revor https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215720#Comment_215720 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=215720#Comment_215720 Tue, 23 Dec 2014 13:54:46 +0000 Paul in Montreal
You can get weather data for the UK for it too.

http://www.nrcan.gc.ca/energy/software-tools/7421

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=216856#Comment_216856 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12901&Focus=216856#Comment_216856 Sun, 11 Jan 2015 18:19:31 +0000 GreenPaddy