Green Building Forum - Simple Heat Loss Calculator Tue, 01 Sep 2026 23:37:41 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=177515#Comment_177515 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=177515#Comment_177515 Sat, 08 Jun 2013 09:57:25 +0100 PeterW
Following a couple of discussions, here is a simple Excel based heat loss calculator and domestic heating sizing method.

Based on the Energy Saving Trust paper fact sheet and calculator, you will need to download both as the instructions are in the PDF

http://www.energysavingtrust.org.uk/Publications2/Housing-professionals/Heating-systems/Domestic-heating-sizing-method-2010-edition

https://docs.google.com/file/d/0B4rLWre5MvQQWm5CMVJ2VTdUcUE/edit?usp=sharing

If you do spot any errors in it please let me know and I will update it

Thanks

Peter:bigsmile:]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=177651#Comment_177651 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=177651#Comment_177651 Mon, 10 Jun 2013 22:00:33 +0100 jamesingram I believe they had a big budget cut when the CONLIB came to power.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217196#Comment_217196 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217196#Comment_217196 Thu, 15 Jan 2015 11:20:49 +0000 Triassic
Where can I find the appropriate heat loss spread sheet?]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217257#Comment_217257 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217257#Comment_217257 Thu, 15 Jan 2015 19:49:35 +0000 djh Posted By: TriassicI'm looking to do the heat loss calculations for my new build.
Which 'the' are you talking about?

Meeting statutory obligations?

Getting an accurate idea of heat load / heat demand?

Something else?]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217262#Comment_217262 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217262#Comment_217262 Thu, 15 Jan 2015 20:11:56 +0000 Triassic Posted By: djh
Getting an accurate idea of heat load / heat demand? So I can size the heating system.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217268#Comment_217268 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217268#Comment_217268 Thu, 15 Jan 2015 20:36:32 +0000 djh So I can size the heating system.
There's a lot of published reports rubbishing SAP, so I'd either go for a dynamic model such as HOT2000 or if your build is within its parameters, trust PHPP.

For heating system sizing, it's the heat load that matters. Plus you need substantial overkill to heat the place from cold after a long holiday or power cut etc. You also need a backup plan for power cuts. But electric fan heaters are cheap, as are camping gas stoves etc.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217272#Comment_217272 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217272#Comment_217272 Thu, 15 Jan 2015 21:22:03 +0000 Triassic
Posted By: djhBut electric fan heaters are cheap, as are camping gas stoves etc.
We currently use an electric fan heater and it's great for heating from cold.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217285#Comment_217285 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217285#Comment_217285 Thu, 15 Jan 2015 22:40:28 +0000 andyman99 Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217316#Comment_217316 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217316#Comment_217316 Fri, 16 Jan 2015 15:00:45 +0000 Triassic
I've just started loading data into Hot2000 and I must admit I had a few head scratching moments and more than a few empty cells, but slowly but surely I'll get there.

I was wondering if there is a user guide as well as YouTube? I've also found some of the insulation thicknesses a bit thin and no obvious user override.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217321#Comment_217321 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=217321#Comment_217321 Fri, 16 Jan 2015 15:18:00 +0000 Paul in Montreal Posted By: TriassicI was wondering if there is a user guide as well as YouTube? I've also found some of the insulation thicknesses a bit thin and no obvious user override.

You can create your own "code" elements with whatever thicknesses you want - the built-in ones are a representative sample, but you can define what you want from the individual material elements available. Being accurate with window sizes, overhangs and location also helps correctly calculate the solar gains. The good thing about hot2000 is that its models have been verified against real test buildings (especially the model it uses for basements and the heatloss into the ground). If you have actual air tightness measurement figures, you can use these, too, to determine the air leakage losses. There are weather files available for the UK - if you can't find them, whisper me your email address and I'll send you the zip file I have.

Paul in Montreal.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=264291#Comment_264291 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=264291#Comment_264291 Mon, 01 Jan 2018 19:12:02 +0000 Jinni King
Also, i stumbled upon the 'missing' Energy Saving Trust paper fact sheet pdf. I've saved it to my google drive...here's a link: https://drive.google.com/open?id=17IKCsiba61Sdw0fSwpZGAe2lMY41qgYx]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306214#Comment_306214 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306214#Comment_306214 Tue, 09 Jul 2024 18:12:31 +0100 Victorianeco Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306225#Comment_306225 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306225#Comment_306225 Wed, 10 Jul 2024 10:17:55 +0100 WillInAberdeen https://heatpunk.co.uk/

BUT

Garbage in = Garbage out

If you don't know accurate ACH and insulation and thermal bridge values to input, then the output will be a best guess, the 'default' values will over size your heating system by 30% or more

BUT

For radiator and UFH sizing that doesn't matter. It costs very little more to fit a big radiator, than to fit a small one. So just fit the biggest you can.]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306226#Comment_306226 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306226#Comment_306226 Wed, 10 Jul 2024 10:44:52 +0100 WillInAberdeen We have big windows on the south rooms, so the solar gains add lots more heat there, than on the north rooms. None of the calculations account for this accurately.

So again, don't worry or rely too much on calculations, none of them are 'right', but you only need 'near enough' for radiator sizing and then round up.

(Sizing the heat pump itself will be a different matter - then you don't want too big a heat pump as they don't run efficiently)]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306230#Comment_306230 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306230#Comment_306230 Wed, 10 Jul 2024 21:06:29 +0100 Victorianeco
Most pumps are inverter type so shouldn't matter too much if oversized anyway?]]> Simple Heat Loss Calculator https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306510#Comment_306510 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=10758&Focus=306510#Comment_306510 Tue, 20 Aug 2024 09:40:16 +0100 cc64
there is a free to use tool

and also a more customisable on for which £18 pcm is charged; worth it]]>