Hi all,

This is a very useful site, I've been reading it and getting ideas for some time, but I think it's time to ask directly for some assistance.

We're building a new timber frame house of about 150 sq m, it will be insulated to well above current requirements. We originally wanted ground source with underfloor heating but have been worried by conflicting advice given to us, and also think we'd have trouble installing it on our land which has quite a few trees, as well as being solid chalk a couple of feet down.

Air source was tempting for a short while but I don't like the noise factor, the large outside unit, the way it stops working if the temperature ever gets really cold.

My plan was then to install the underfloor but not connect it yet (maybe wait for air source heating to improve?). We'd have a couple of wood burning stoves, one with a back boiler to provide DHW, backed up by off peak immersion heater.

I then read about pellet stoves with back boilers and we're wondering whether this would be a better option. However we don't know anyone with pellet boilers/stoves and are concerned that it may be expensive to run, inflexible and also expensive to install. And who knows whether we'd even need it - in a well insulated house would the 2 stoves be sufficient?

Would this option work with underfloor heating? If so would we need a thermal store or something??

Trying to get information on these things is really difficult; it seems like we'd be pioneers if we used this technology. Or possibly idiots.

Any help, input etc would be most welcome from you experts out there.

Thanks,
John

Hi Tony

Thanks for the reply. Why timber frame? Why not?? That's what the architect designed, and I understand it's easier to get higher insulation with timber frame. Our choices were very limited by planning restrictions in the village we're building in.

GSHP might be ok but there is not enough room for 2 x 30 or 40 metre trenches 5 metres apart as the land has lots of trees which we don't want to remove. We can't afford a borehole. And also I don't see how chalk could be great for GSHP. Clay, maybe.

ASHP stops working (as I understand it), depending on model, at temps of -5 to -17 degrees - which is when you'd really need it. Plus it has a whacking great fan which despite the manufacters claims has to make noise, and which is exposed to the elements. I love the claimed efficiencies of these technologies but am not reassured by the answers that I've been given by suppliers, some of who I suspect were selling double glazing a few months ago.

That's why we're looking at stoves, and latterly pellet stoves.

Cheers

or no heating at all John, where do you live? chalk and - 5 to -17 dont go together.

Why not timber frame. It is too responsive thermally ( gets cold at night ) and too hot in summer.

Solid masonry will respond much more slowly ( be much more comfortable to live in) is able to store free solar gain, has a solid feel,

Either can be insulated just as well. Plenty of discussion on this subject on here -- there are two camps I m in the heavyweight one though the first house I built was timber frame I now hate it and would not live in one.

Hi again Tony,

Thanks for all your time, by the way, it's very good to know there are people out there prepared to share their knowledge with the rest of us.

It's way too late to discuss the relative merits of timber frame vs. masonry as the build has started and we're waiting for our carpenter to be able to start (and hoping he actually will, one day). However the SAP calcs came back very positive, as I understand it, and we're going to spend a fortune on Celatex (I know, for all you dedicated greenies out there, that we should be using sheep wool or recycled underwear, but nothing comes close to price/performance to Celatex). So we assume all will be well. After all houses have been built that way for hundreds of years.

I also know that temperatures in rural Berkshire rarely go down to -5 let alone -17 but it seems daft to install something that's not going to work if/when it does get that cold.

So I'm hopeful that we don't actually need anything other than the stoves, but as I am basing this hope on no real knowledge at all I feel that we should have a standby option in case it's too cold and the wife runs off back to her mother leaving me huddled in front of a wood burning stove...

That's why I want to install the underfloor pipes even if we don't connect it up. But that raises questions in itself! Phew.

John

Thanks, yes we are taking photos. As I have said the house is to be insulated well beyond the current stipulations of the building regs, we're not worried about insulation. Our concern is heating and DHW.

Does anyone have any information or experience of pellet stoves/boiler combinations, especially with underfloor heating as per my original question?

Cheers
John

Hi Sipman,

Many thanks for your informative reply, it's exactly the sort of information we need to help us (try to) make the right decision. I'm not sure we can factor in MVHR but it is something to bear in mind, and would certainly move the heat around the building. I'm concerned we might be nice and snug downstairs but cold upstairs.

Solar is something we want but I can foresee another giant struggle with our lovable local council to try to get permission (AONB, conservation area etc though they would be out of sight). We intend to build the house ready for solar to be fitted at a later stage though.

It's really useful to hear about your experiences and gives me much more confidence that we'll actually be OK. Do you, however, think we'd be OK with our stoves without a heat distribution/recovery system sort of thing, or could we end up with that cold bedroom scenario?

Thanks again,
John

Hi Iain

Thanks for this, yes I think I agree; we're in a bit of a dilemma. However the choice to me, as I see it today at least, is either air source or pellet stove/boiler. Either of these should allow the underfloor heating to work and supply DHW but I'm leaning towards the pellet stove as it is probably more straightforward as it doesn't require extra heating to the water supply.

As you can tell I am committed to selecting the right system for us and if it doesn't work properly it certainly won't be for the lack of research and effort.

John