SteamyTea Posted March 29, 2021 Share Posted March 29, 2021 (edited) 36 minutes ago, stubiff said: Would the room with wood fibre boards use less energy to maintain a certain room temp, Yes, or No, depends on the 'something else'. Energy cannot be created, it can only change its form. So, stored energy has to be created first, and this is where the confusion comes in. If, for instance, you need to raise the temperature of the building by 2° C, and you have 10 tonnes to heat, assuming brick/concrete, with a specific heat capacity of 0.8 kJ/kg.K, then you need 16,000 kJ (4.44 kWh), while at the same time as heating say 100 kg of air, that has a SHC of 1 kJ/kg.K, so an extra 200 kJ (0.056 kWh). But if you have a timber/insulation combination, you may be reducing the 10 tonnes to 2 tonnes, but the SHC may be higher, say 1.3 kJ/kg.K, then that initial heating load is reduced to 5,200 kJ (1.44 kWh), while the air heating load is the same. Now people argue that you get that difference (3 kWh) back when you turn the heating off, except some of it has leaked out to the atmosphere/ground. So by having a larger store of energy, you have a larger amount to loose, and as heat loss is non proportional, the larger the temperature differences, the larger the losses, and the faster those losses happen. Controlling losses, and gains, is the key to temperature stability, this is why people put blinds on oversized windows and have MVHR fitted. In the UK it is a rare day that the weather conditions are idea of stable passive heating, or cooling for that matter. Spend your time and money on insulation and airtightness, not on large windows, tonnes of concrete and aftermarket fixes. Edited March 29, 2021 by SteamyTea 3 Link to comment Share on other sites More sharing options...
stubiff Posted March 29, 2021 Share Posted March 29, 2021 (edited) Sorry, should have added. U value of 0.15 say, airtight, timber frame. 'Something else' could be PUR or similar. I.e. something a lot less dense. Edited March 29, 2021 by stubiff Link to comment Share on other sites More sharing options...
SteamyTea Posted March 29, 2021 Share Posted March 29, 2021 Just now, stubiff said: Sorry, should have added. U value of 0.15 say, airtight. The U-Value is of little consequence when looking at energy storage, it is, in effect, just the speed at which the losses happen (why it is measured in watts, not joules). Realistically, the U-Value will be similar i.e. your 1.5 W/m2.K, just that you have a larger amount to loose when you have a larger store. Better off spending your cash to get the U-Value down, you only spend that money once and it is a marginal increase in cost for the extra material, the fitting is about the same cost. Link to comment Share on other sites More sharing options...
stubiff Posted March 29, 2021 Share Posted March 29, 2021 @SteamyTea Thanks very much Link to comment Share on other sites More sharing options...
Pocster Posted May 8 Share Posted May 8 Bump Link to comment Share on other sites More sharing options...
joe90 Posted May 8 Share Posted May 8 It’s too late to wind Jeremy up, he left ages ago, but his “Dr Sidekick” will be along shortly to explain the science and maths 😴 1 Link to comment Share on other sites More sharing options...
JohnMo Posted May 8 Share Posted May 8 31 minutes ago, joe90 said: It’s too late to wind Jeremy up, he left ages ago, but his “Dr Sidekick” will be along shortly to explain the science and maths 😴 Didn't everyone just loose the will to live on this thread, to resurrect it again. @Pocster is just having fun with you. 1 Link to comment Share on other sites More sharing options...
joe90 Posted May 8 Share Posted May 8 2 hours ago, JohnMo said: Didn't everyone just loose the will to live on this thread, to resurrect it again. @Pocster is just having fun with you. (I still call it thermal mass, but not in front of steamy tea) 🤣. However I did learn stuff from that thread like decrement delay. Link to comment Share on other sites More sharing options...
Pocster Posted May 9 Share Posted May 9 (edited) But I feel this thread hasn’t resolved the great thermal mass myth . Discuss ! 😊 ( slow day for me ) Edited May 9 by Pocster Link to comment Share on other sites More sharing options...
joe90 Posted May 9 Share Posted May 9 11 minutes ago, Pocster said: slow day for me No wonder your build is not finished? 🤷♂️ Link to comment Share on other sites More sharing options...
Pocster Posted May 9 Share Posted May 9 8 minutes ago, joe90 said: No wonder your build is not finished? 🤷♂️ New toys arriving today Link to comment Share on other sites More sharing options...
joe90 Posted May 9 Share Posted May 9 Just now, Pocster said: New toys arriving today Work toys or otherwise 😜 Link to comment Share on other sites More sharing options...
Pocster Posted May 9 Share Posted May 9 6 minutes ago, joe90 said: Work toys or otherwise 😜 Otherwise 😉 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted May 9 Share Posted May 9 4 hours ago, Pocster said: But I feel this thread hasn’t resolved the great thermal mass myth Has is my mind. Even if there was a measurable advantage, it would be swammed by normal activity. Link to comment Share on other sites More sharing options...
scottishjohn Posted May 9 Share Posted May 9 (edited) to add my two pence worth my house has 6-700mm granite stone walls ,then 50mm air gap then 150mm t/f and insulation I can say now that mass matters to making a stable temp even now with still no bifolds fitted --but just blanked off with ill fitting osb -no heating as yet the temp inside is stable and in rooms that are finshed that get sun -and bear in mind these are not huge windows in old stone house the temp goes up noticably so much there have been days when joiners and plasters have complained of it being colder inside than out and upsatairs where it is all plasetered etc it is much warmer . but yes i agree with others that spending on insulation and stopping air leaks sghould be top priority on any house-- Edited May 9 by scottishjohn 1 Link to comment Share on other sites More sharing options...
Pocster Posted May 10 Share Posted May 10 I like this thread because I don’t care about it . It’s really old and @Jeremy Harris started it so it deserves resurrection just for fun . My personal opinion on “ thermal mass myth “ is zero . Link to comment Share on other sites More sharing options...
Iceverge Posted May 10 Share Posted May 10 I have a suspicion that "thermal mass" induced temperature stability has an awful lot more to do with the tiny windows in old buildings rather than any other imaginary benefits. Link to comment Share on other sites More sharing options...
Pocster Posted May 10 Share Posted May 10 1 hour ago, Iceverge said: I have a suspicion that "thermal mass" induced temperature stability has an awful lot more to do with the tiny windows in old buildings rather than any other imaginary benefits. I thought that also ( I didn’t , but felt as I had resurrected this zombie thread I should attempt to comment ) 1 Link to comment Share on other sites More sharing options...
MikeSharp01 Posted May 10 Share Posted May 10 Yes if feels right to feed a Zombie - it just keeps shuffling along with with its limp hands on the ends of outstretched arms emitting a constant moaning noise. I wonder if Simon Pegg is on the forum, he would know what to do. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted May 10 Share Posted May 10 1 hour ago, MikeSharp01 said: wonder if Simon Pegg is not the forum, he would know what to do. Not today, he was in our restaurant and hour ago. 1 Link to comment Share on other sites More sharing options...
MikeSharp01 Posted May 10 Share Posted May 10 Sans Zombies one presumes! Link to comment Share on other sites More sharing options...
SteamyTea Posted May 10 Share Posted May 10 1 hour ago, MikeSharp01 said: Sans Zombies one presumes! Yes, was all peaceful and very civilised today. The shit happens come the next bank holiday, then the relentless months till November. Link to comment Share on other sites More sharing options...
joe90 Posted May 10 Share Posted May 10 I am glad I am in the Forest and not Cornwall now the summer is coming , sooo much quieter up here. Link to comment Share on other sites More sharing options...
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