Wed, 29 Apr 2026 22:56:18 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9685#Comment_9685 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9685#Comment_9685 Tue, 20 Nov 2007 13:05:34 +0000 Aguillar
Option 1; Underfloor heating running off a wood burning stove with back boiler.
Think we need an accumulator and pumps - concerned that pumps may require too much electricity given we are not on the mains and don't yet know how good a wind site we have here.

Option 2; Pumped radiators running off a wood burning stove with back boiler.
Don't need an accumulator but still need a pump, same concern with electrical requirement.

Option 3; Thermosyphoning radiators running off a wood burning stove with back boiler.
No pumps required but due to restrictions on all pipes [min 28mm copper] needing to rise along their entire length from boiler to radiators it is not possible to have radiators in some rooms without pipes crossing in front of windows a few feet up and having a couple of radiators half way up the walls..

Option 4; Two wood burning stoves without radiators [well one would have a back boiler for heating domestic hot water and would have a radiator for pressure relief]
Nice and simple to install but will the heat percolate through the rooms enough? Building regs require us to put sound insulation in the internal walls and we are worried that this could prevent heat moving from heated rooms to unheated rooms.

Any comments/ suggestions very gratefully received!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9689#Comment_9689 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9689#Comment_9689 Tue, 20 Nov 2007 14:04:33 +0000 tony
Solar hot water is a great idea -- my advice is to oversize it all.

What is your air leakage rate going to be?

Burning wood adds CO2 to the atmosphere.

Could you do external insulation to the walls?

Thermosyphons with big pipes can work pretty much level ( 1:100 ) so long as it goes upstairs too.

I would not insulate the floor except arround the edges and may be only vertically there. There is a whole thread about U values of floors.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9690#Comment_9690 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9690#Comment_9690 Tue, 20 Nov 2007 15:25:28 +0000 Tuna
It sounds like quite a challenge - is it a single floor building, and how many rooms? I'd possibly consider two stoves and then start to work on ways to get the heat around... you could have a stove in one room and route the stack up through another, or back boiler plus a small rad in the room behind etc.

As it's only two residents, you might get a lot of mileage out of designing the room layout to suit more localised heating - say a open plan living/eating/cooking area and a seperate sleeping zone.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9692#Comment_9692 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9692#Comment_9692 Tue, 20 Nov 2007 16:43:12 +0000 Paul in Montreal Posted By: Tunatony - Surely MHVR off grid is a non starter?

Don't be so sure. The MHRV linked below consumes around 100W at full speed:

http://www.vanee-ventilation.com/eng/pdf/Serie%20HE/Prod.Sheet%201.3%20and%201000%20HE.pdf

Should easily be doable with a small PV array.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9701#Comment_9701 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9701#Comment_9701 Tue, 20 Nov 2007 19:49:40 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9710#Comment_9710 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9710#Comment_9710 Tue, 20 Nov 2007 22:08:57 +0000 andytk
If so I wouldn't be so worried about having central heating circulating pumps but if you're planning to have any form of heating plumbed into a back boiler on a wood burner you will have to have a thermosyphon heat dump radiator (maybe outside) as the regs require it in case of failure of circulating pump failure/domestic HW tank overheat.

Its also worth bearing in mind that if fitted, the back boiler will always reduce the direct output of the wood stove into the room, even if its only dumping the heat into the thermosyphon dump load. You can't run the wood stove without circulating the back boiler.

For simplicity I'd go for two smaller woodburners as its only 120m2.

But I'm not an expert and free advice is always worth exactly what you pay for it. ie. nowt.

Andy]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9711#Comment_9711 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9711#Comment_9711 Tue, 20 Nov 2007 22:47:14 +0000 Nickysells1
If not you are into multi fuel burners using coal/anthracite which is of course not good.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9713#Comment_9713 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9713#Comment_9713 Tue, 20 Nov 2007 23:51:44 +0000 tony
If you were really clever you could renovate it in such a way that no formal heating was needed.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9716#Comment_9716 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9716#Comment_9716 Wed, 21 Nov 2007 04:23:35 +0000 Terry Most MVHR suppliers have a range of models, some with low electrical consumption which are obviously a bit pricier.
If you have Solar HW you will be needing a tank so why not combine the wood stove and solar into a decent sized thermal store which will only require a periodic burn to get the store up to temperature.
What sort of electric consumption do pumps have? Wouldn't have thought it was outside the capability of an off grid system???]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9726#Comment_9726 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=890&Focus=9726#Comment_9726 Wed, 21 Nov 2007 16:06:09 +0000 Aguillar We had hoped to be entirely passively heated, but have discovered that airtightness is likely to be a problem given it is a barn conversion not a new build. The planning authorities have refused us permission to have enough South facing glazing to go passive too.
There will be a battery bank but don't want to have too much running off it. Heating pumps in particular worried us as still, foggy periods without wind or solar would be periods of high heat requirement.
We have seen some very low power circulation pumps so are now a bit more confident of a more 'normal' pumped rad system.
Had hoped to keep clear of MVHR but are keeping it on the consider list..
In order to fully consider going without radiators [other than as heat dumps off a back boiler used for DHW] is there a way to estimate heat percolation between rooms?]]>