F113tch Posted January 20, 2022 Share Posted January 20, 2022 Hi All! I have only just stumbled across this site but so glad I did! I am in the middle of a c. 350m2 new build near York with the build now being watertight. Hoping to get my GSHP(!) installed in time to benefit from the RHI, I was disappointed to hear this week of supply issues from the pump manufacturer, therefore I set about trying to find an alternate supplier, which lead me to this site… Following lots of hours of reading as to the relative merits of ASHP’s (there is no mains gas on site), I am now quickly looking to re-design the proposed system. The house is brick and block construction with 150mm cavities (100mm insulation and 50mm air gap). On top of the 200mm(?) concrete slab is 100mm insulation with the plan to fit UFH in a screed above this. The 1st floor is block and beam construction with no plan to put insulation above it (this was a recommendation from the architect but unsure if this is good advice or not?). The 1st floor is also to have UFH in a c. 65mm screed. I am looking to fit an MVHR system to the property but know little about them, other than what I have read on here over the last few days, so have contacted BPC Ventilation for a design. The plan, when funds allow(!), is to fit solar PV (possibly with battery storage?), to the South facing roof. I have lots of questions regarding ASHP, UFH and MVHR but I am trying to find answers through searching the forum before asking! Thanks to everyone for sharing a wealth of knowledge on this site! Steve. Link to comment Share on other sites More sharing options...
MikeSharp01 Posted January 20, 2022 Share Posted January 20, 2022 Welcome to THE forum for people like us. Looks like an interesting project - if you will pardon the pun - keep digging Link to comment Share on other sites More sharing options...
Merlolly Posted January 21, 2022 Share Posted January 21, 2022 Hi Steve, I've just posted our project and there's many similarities with our build! We're just about to put walls up so you are a few steps ahead and like yourself, avidly reading through the forum before posting too many questions GSHP vs ASHP we're also gas free on our site and after much knashing of teeth have finally decided to go Air Source. We were absolutely gutted to move away from the ground based (we'd commissioned all the surveys etc) but personally it made a big difference to our stress levels, not trying to cram everything together in order to get certified before the end of March - however, as you may be aware there is a replacement scheme for which self-builders are eligable to get £5k towards a sustainable heat source - link to info on Clean Heat Grant here UFH - I've read that you can design your own layout for free but we managed to get a free design from a company tilting for our work. C MVHR - we've some designeds commissioned by ADM Systems that seem great - over this weekend I'll post up what we have as we have a few questions and would be happy to compare notes Solar PV - similar story to yourself, we put it on the back burner due to cost but have just been recently encouraged by the saving of using integrated system to elevate that idea to the forefront, less tiles to buy. Unsure whether it works out financially feasible but hopefully so! Best of luck and I'm sure we'll cross paths in this awesome forum Cheers, Merl Link to comment Share on other sites More sharing options...
Marvin Posted January 21, 2022 Share Posted January 21, 2022 Hi @F113tch Welcome. I believe that the best energy saving combo is: Insulation, insulation, insulation. Airtightness through design, and construction of build, along with MVHR which gives you fresh air and less loss of the building temperature. Heating with an ASHP, espically if you have PV. ( Here we have a cold bright day and 3kW power at present going towards heating and charging the electric car. We renovated our bungalow which has all the above: 100m2. Below zero last night: 8kWhs to keep the house above 19C. Good luck with your plans. M Link to comment Share on other sites More sharing options...
F113tch Posted January 21, 2022 Author Share Posted January 21, 2022 Thanks for the warm welcome guys! I was sold on a GSHP in 2019 and have had this in mind ever since, however this forum has convinced me otherwise. I currently have a design for a 12kW NIBE GSHP system and my question is; can the NIBE GSHP pump be exchanged for a 12kW ASHP? I assume a kW is a kW irrespective of source!? However, from the reading I have done on here, 12kW seems quite a large pump for the c. 350m2 house!? I have had SAP calculations completed but I am a little baffles by the results to be honest and not sure how this helps me size an appropriate pump.. I really thought I had done a great job with the insulation but it appears I haven’t done that good a job at all…! (If only I’d come across this site earlier in proceedings!) ‘ The original UFH design has pipe spacing at 200mm centres but I’ve read on the is forum that 150mm or 100mm centres give improved heating. I am going for a wet plaster for increased air-tightness to improve the effectiveness of the MVHR. My only issue to overcome with the MVHW is how to run the ducting in the vaulted ceilings with cold-roof construction!? Steve. Link to comment Share on other sites More sharing options...
MeMyselfandI Posted May 7, 2022 Share Posted May 7, 2022 I would heavily query the lack of insulation over the beam and block first floor. The LABC state : "Intermediate floors Although Building Regulations do not normally require intermediate floors within homes to be insulated to prevent heat loss, where underfloor heating is installed, insulation will need to be incorporated to direct heat flow upwards." Taken from, https://www.labcwarranty.co.uk/blog/floor-screeds-and-underfloor-heating-a-best-practice-guide/ See also https://www.underfloorheatingsystems.co.uk/self-install-information/questions-and-answers/i-have-block-and-beam-construction-on-the-first-floor-do-i-need-to-use-any-insulation-for-the-hydronic-underfloor-heating/ for an UFH manufacturers recommendations ...quite simply, you only want to be heating the screed of the floor with the UFH system, you don't want to be using oodles more energy than needed by heating the full structure of the beam and block floor as well. commercial link removed Link to comment Share on other sites More sharing options...
ADLIan Posted May 7, 2022 Share Posted May 7, 2022 See also new Approach Doc L due next month-insulation for intermediate floors with underfloor heating. Link to comment Share on other sites More sharing options...
Nickfromwales Posted May 7, 2022 Share Posted May 7, 2022 43 minutes ago, ADLIan said: See also new Approach Doc L due next month-insulation for intermediate floors with underfloor heating. Eh? Within the insulated envelope? Link to comment Share on other sites More sharing options...
Nickfromwales Posted May 7, 2022 Share Posted May 7, 2022 Ah, beer sometimes isn’t a help. Is that reference to the uplift in the basic ( minimum ) permissible target values? Basically Irish BRegs creeping over here. Link to comment Share on other sites More sharing options...
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