Amateur bob Posted October 26, 2020 Share Posted October 26, 2020 Im in the process of planning a self build 170m2 house in the countryside, no gas available so thinking ill need to go for an ASHP, could anyone advise me of what type of ASHP to go for and a rough cost? Also should i be looking at underfloor heating to increase effficiency? Thanks Link to comment Share on other sites More sharing options...
SteamyTea Posted October 26, 2020 Share Posted October 26, 2020 (edited) Your house is a similar size to @joe90s, he fitted his own I think. And yes to UFH if you have a decent amount of insulation under it. Edited October 26, 2020 by SteamyTea Link to comment Share on other sites More sharing options...
JamesP Posted October 26, 2020 Share Posted October 26, 2020 (edited) New self build, about 280sqm, Had 8.5 Ecodan supplied and fitted for £8514. Just filling out the RHI application. Payments over 7 years £6370. Will depend on your EPC. Many have self fitted similar system. Edited October 26, 2020 by JamesP Link to comment Share on other sites More sharing options...
joe90 Posted October 26, 2020 Share Posted October 26, 2020 45 minutes ago, SteamyTea said: Your house is a similar size to @joe90s, he fitted his own I think. And yes to UFH if you have a decent amount of insulation under it. yes, I bought a new ASHP on Ebay fir cash and installed it myself, not difficult (with help on this forum from others), my new build is passive esk (I.e passive principles but not certified levels or equipment). UFH is a must IMO with lots of insulation under the floor. Link to comment Share on other sites More sharing options...
Simtronic Posted October 27, 2020 Share Posted October 27, 2020 (edited) I would look for an inverter driven monoblock one of the latest ones that run on the more environmentally friendly R32 COP, size and noise levels are important factors. Price so depends on your needs, preferences and expectations. I think underfloor heating is a no brainer in a self build, I know it is a lot harder to retro fit. Good luck Edited October 27, 2020 by Simtronic Link to comment Share on other sites More sharing options...
SteamyTea Posted October 27, 2020 Share Posted October 27, 2020 13 minutes ago, Simtronic said: more environmentally friendly R32 Still has a GWP of 675. CO2 is 1 I really wish the industry would hurry up and move over to CO2 pumps. Link to comment Share on other sites More sharing options...
Simtronic Posted October 27, 2020 Share Posted October 27, 2020 Maybe there are other reasons why they aren't using CO2, how effective is it and at what cost? Link to comment Share on other sites More sharing options...
PeterW Posted October 27, 2020 Share Posted October 27, 2020 2 minutes ago, SteamyTea said: Still has a GWP of 675. CO2 is 1 I really wish the industry would hurry up and move over to CO2 pumps. They tried. Sanyo had them in the market over 10 years ago and we had one installed on a commercial build. Nightmare to get spares for and need lots of specialist tools and equipment to service due to different gas pressures that are used in the units. From memory Sanyo left that market in about 2012 and went back to the standard refrigerants. Link to comment Share on other sites More sharing options...
SteamyTea Posted October 27, 2020 Share Posted October 27, 2020 3 minutes ago, Simtronic said: Maybe there are other reasons why they aren't using CO2 Yes, I think it is the lack of skills in the plumbing industry. CO2 heat pumps have been around decades now. Link to comment Share on other sites More sharing options...
Simtronic Posted October 27, 2020 Share Posted October 27, 2020 Just been reading up on it and Denso and Stiebel Eltron are bringing a CO2 heat-pump out for residential use. As far as I can see it is only available in Japan at the moment. Hopefully it will see a revival but how long until available here? Link to comment Share on other sites More sharing options...
Amateur bob Posted October 27, 2020 Author Share Posted October 27, 2020 42 minutes ago, Simtronic said: I would look for an inverter driven monoblock one of the latest ones that run on the more environmentally friendly R32 COP, size and noise levels are important factors. Price so depends on your needs, preferences and expectations. I think underfloor heating is a no brainer in a self build, I know it is a lot harder to retro fit. Good luck ok origionally i wasnt going to fit underfloor heating to save money but hearing it works best with this system it looks like ill now need to look into it, can anyone give me a rough cost for it? Link to comment Share on other sites More sharing options...
Simtronic Posted October 27, 2020 Share Posted October 27, 2020 (edited) I built my own from bits from ebay around £500 for pipes spreader plates, 8 port manifold and blender. But if I factor in my time a lot more edit: this was 8 years ago and doesn't include a whole lot of insulation Edited October 27, 2020 by Simtronic Link to comment Share on other sites More sharing options...
Amateur bob Posted October 27, 2020 Author Share Posted October 27, 2020 5 minutes ago, Simtronic said: I built my own from bits from ebay around £500 for pipes spreader plates, 8 port manifold and blender. But if I factor in my time a lot more would a wet or electric system work best with the ASHP? not needing to have radiators will bring the costs down a bit? Link to comment Share on other sites More sharing options...
Simtronic Posted October 27, 2020 Share Posted October 27, 2020 ASHPs take heat from the air and move it to water so wet is the only option using ashp. Electric underfloor heating is very expensive to run unless you only use it when sunny and have a massive solar array. Not really viable in the UK unless you have money to burn 1 Link to comment Share on other sites More sharing options...
joe90 Posted October 27, 2020 Share Posted October 27, 2020 (edited) Biggest expense/work with UFH is the insulation/digging required. With a new build this can be planned fir so less hassle/expense, I have 200mm of PIR on my slab and 70mm flow screed with UFH pipes in it. Some put their pipes in the slab Tied to the mesh. Installing pipes is a DIY job and pipework not too expensive. Edited October 27, 2020 by joe90 Link to comment Share on other sites More sharing options...
Jilly Posted October 28, 2020 Share Posted October 28, 2020 What would be the minimum viable insulation for UFH ( retro fit concrete slab) only 150mm available...? Link to comment Share on other sites More sharing options...
joe90 Posted October 28, 2020 Share Posted October 28, 2020 18 minutes ago, Jilly said: What would be the minimum viable insulation for UFH ( retro fit concrete slab) only 150mm available...? So your slab is already in?. That only gives you 100mm insulation if you had 50mm screed with pipes in!!!. Link to comment Share on other sites More sharing options...
PeterW Posted October 28, 2020 Share Posted October 28, 2020 Finished floor surface @Jilly ..? Could always float an engineered timber floor over the top of battens with a pug mix between so you could get away with 120mm of insulation with 15mm pipe and then 18mm flooring 1 Link to comment Share on other sites More sharing options...
Moonshine Posted October 28, 2020 Share Posted October 28, 2020 1 minute ago, PeterW said: so you could get away with 120mm of insulation Also if that insulation wasn't standard PIR with an R value of 0.022, but of a higher spec like phenolic foam with an r value of 0.018. Link to comment Share on other sites More sharing options...
Jilly Posted October 29, 2020 Share Posted October 29, 2020 19 hours ago, joe90 said: So your slab is already in?. That only gives you 100mm insulation if you had 50mm screed with pipes in!!!. Yes, it's a conversion. To dig out the old slab would have necessitated underpinning... Link to comment Share on other sites More sharing options...
SteamyTea Posted October 29, 2020 Share Posted October 29, 2020 You may find that UFH is not the best option. Have you considered 'skirting radiators'? 1 Link to comment Share on other sites More sharing options...
Amateur bob Posted October 29, 2020 Author Share Posted October 29, 2020 2 hours ago, SteamyTea said: You may find that UFH is not the best option. Have you considered 'skirting radiators'? how not? at the moment im considering uh downstairs and radiators upstairs Link to comment Share on other sites More sharing options...
SteamyTea Posted October 29, 2020 Share Posted October 29, 2020 41 minutes ago, Amateur bob said: how not? at the moment im considering uh downstairs and radiators upstairs Because of the thermal losses through the floor and into the ground. Just a case of working out the losses and see what comes out in the wash. Link to comment Share on other sites More sharing options...
Jilly Posted November 1, 2020 Share Posted November 1, 2020 On 29/10/2020 at 12:57, Amateur bob said: how not? at the moment im considering uh downstairs and radiators upstairs I think @steamytea meant me, sorry my question hijacked the thread! Link to comment Share on other sites More sharing options...
SteamyTea Posted November 1, 2020 Share Posted November 1, 2020 7 minutes ago, Jilly said: I think @steamytea meant me, sorry my question hijacked the thread! Yes I did. 1 Link to comment Share on other sites More sharing options...
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