Advice on heating system for build

sandy2000

Hi everyone. I'm about to start a building project soon and have been reading this forum to try and educate myself about it as I'm pretty clueless about building stuff (it's really a great resource so thanks to everyone).

Ill soon need to make decisions about what's going to go in so was wondering if anyone had any advice about a heating system. It's a 1930's semi-d around 1500 sq foot at the moment. We'll be insulating it as best we can as well as building an extension that will make it around 2100 sq foot in total. Its currently gas central heating with some fireplaces and a small stove that's not linked to the heating system. The plan is to put in underfloor heating. The house is south facing so solar thermal has been suggested but Ive seen some doubts on here about if it's worth it. But a lot of them are from older posts and maybe it's got better/cheaper?

If anyone has any suggestions, Id love to hear them. Thanks!

MicktheMan

sandy2000 wrote: »

1. Hi everyone. I'm about to start a building project soon and have been reading this forum to try and educate myself about it as I'm pretty clueless about building stuff (it's really a great resource so thanks to everyone).

2. We'll be insulating it as best we can as well as building an extension that will make it around 2100 sq foot in total. Its currently gas central heating with some fireplaces and a small stove that's not linked to the heating system.

3. The plan is to put in underfloor heating.

4. The house is south facing so solar thermal has been suggested but Ive seen some doubts on here about if it's worth it. But a lot of them are from older posts and maybe it's got better/cheaper?

5. If anyone has any suggestions, Id love to hear them. Thanks!

1. In that case, perhaps hiring in a professional might be a better idea rather than looking for opinions from randomers on the internet. You will have plenty of time to regret it if you get it wrong.
2. Define "as best we can". What about air tightness? And ventilation? What will be your heat load and heat demand when done? Who is ensuring b.reg compliance?
3. UF in retrofits is best avoided unless a full new thermal bridge free floor slab is planned. Also mixing UF (low temp) with radiators (high temp) is rarely a good idea.
4. Solar thermal would be on the bottom of my list.
5. Hire in an independent professional who can go through your plans and advise you appropriately. Do not take the advice of anyone who is trying to sell you something. Be prepared to be told complete opposites by so called experts, the fella in the pub and everyone in between (me being one of them:))

sandy2000

Thanks Mick, that's helpful. But like I said, Im a bit clueless. What do you mean by professionals? Someone to do a BER assessment/energy audit? We have an architect and QS but it was them that suggested the solar which is why I got a bit concerned because of what Id read on here before. When I look at heating systems on google, all you get is people selling you things so I dont think they're likely to give me the independent advice you're talking about.
Happy to get recommendations by PM from anyone on this forum if you have them.

monseiur

Hi
I'm not so sure that under floor heating is all it's cracked up to be - I'd think twice before installing it especially considering that 60% of your house when extension is added will be from the 1930's to an extent.

Dry line all 'outside' walls with 65mm insulated slab, pay special attention to reveals at doors & windows re. cold bridging etc.
Fit good quality double or triple glazed windows & doors (consider a storm porch)
Remove existing floor and replace with screed over 60mm insulation, assuming that's practical.
Insulate attic with 300mm Rockwool or similar insulation
Close up all fireplaces including top of chimney flues except stove.
Replace all central heating piping & rads (and perhaps boiler) with modern more efficient zoned system in both old and new build with TRV's, stats etc. etc. there may be a grant for this from SEAI - worth investigating.

I guess I didn't exactly answer the question you asked but.......
M.

MicktheMan

sandy2000 wrote: »

Thanks Mick, that's helpful. But like I said, Im a bit clueless. What do you mean by professionals? Someone to do a BER assessment/energy audit? We have an architect and QS but it was them that suggested the solar which is why I got a bit concerned because of what Id read on here before. When I look at heating systems on google, all you get is people selling you things so I dont think they're likely to give me the independent advice you're talking about.
Happy to get recommendations by PM from anyone on this forum if you have them.

Sandy, if you're looking for recommendations, then perhaps your general location would be useful to know.

Did your arch mention anything about air tightness or ventilation? If not, then ask him/her about it. Ask what level of AT did they achieve on their last 1/2/3 projects of this kind and how did they do it. If you get vague answers or are told your AT target will be in accordance with the b.regs, I would seriously look for another.

sandy2000

Sorry Mick, that makes sense. Im based in North Wicklow area. The architect had mentioned that we would need to look into ventilation systems but I hadn't pressed him for specifics on it. Ill get into it now though.