tex360

joth, thanks for this thought. we both have a tiny window 'overlooking' the alley. its closed off one end, so no passage needed. good thought, thank you v much.. if anyone has any make / model names that might fit such arrangement (i dont thin a split with the pumps in the house will be accepted by other half btw) please do share so I can investigate. thx again

BillT and Ferdinand - thank you also - I shall investigate and will reply soon. I'll follow that calculation link. thanks v much! Windows open upstairs is something i need clamp down on... yes we have trickle vents in certain windows.. the double glazed patio doors are 30 yrs old and theres a single glazed door on the kitchen. You are right, we need consider those. I've told the mrs she can pay the elec and gas bill from now on, I suspect this will focus things:) NB the EPC says: "The primary energy use for this property per year is 148 kilowatt hours per square metre (kWh/m2)." is that what you wanted? ta

IanR - very creative. thank you, will consider. And good info re the pipes and split considerations, and re the MSC requirements. I will research. thank you!

Ok, ta. Anyone please able to answer my other questions please? TIA!

thanks for the graph btw, what ratio extra elec for 1000kwh has heat did you assume please. 3000kwh seems to equate to c. 1100 elec kwh from your experience? thats an approx elec cost range of 500kwh (c £100 per month) to 1100kwh (c £220 pm) over the months we use space heating. I still cant see a way to heat the DHW from an ASHP, if I CANNOT fit it in the alley. And I still dont have a definitive reason why not ( is that location banned by actual law? or do I need apply for planning permission?) OK, locating an ASAHP under the rear window may be possible if we lift the floor and route the ASHP output to where the current gas boiler is, and heat the radiators and DHW cylinder that way. But locating the ASHP to the right side of the house - a far better location - where I also have a couple radiators - would surely still be OK for heating only. Maybe my next step on this journey is to abandon ASHP for now - until the models available inc thinner units! - and focus on cutting gas usage.

I agree 100%! I'd like the ground floor heated and keep the doors closed! let convection take care of the upstairs... we are in Uk, its not cold !

Hi again I looked up the 'technical report' from Ovo's assessors, here's the only page with any reference to numbers. Sorry this is all I presently have to indicate the losses. Here's our per-month kWh actuals for elec and gas, for 2020 / 2021 to date: Oct to March is about 12000 of the years' gas, ETA actually 19000 in 2020, perhaps 16000kwh in '21. Usage Elec kWh Gas kWh Jan 2020 496 2581 Feb 2020 501 2388 Mar 2020 447 2304 Apr 2020 414 2304 May 2020 363 993 Jun 2020 360 716 Jul 2020 340 472 Aug 2020 1441 409 Sep 2020 540 779 Oct 2020 642 1581 Nov 2020 695 2227 Dec 2020 696 2227 2020 total 6935 18981 Jan 2021 770 2736 Feb 2021 751 3000 Mar 2021 439 654 Apr 2021 654 256 May 2021 256 380 Jun 2021 380 503 Jul 2021 503 438 Aug 2021 438 500 Sep 2021 331 244 Oct 2021 not yet not yet Nov 2021 not yet not yet Dec 2021 not yet not yet 2021 total 4522 8711 (to date) (to date) so I need to: a. Confirm the losses and sizing for the ASHP. I need find someone to measure this properly and do the sizing for the pump and radiators. Thanks for your comments re kWH not being the proper measures of heat loss/needs. b. Find a pump of correct size that fits, and consider other locations (under the window etc). The side passage is inappropriate (why though? noise? Closeness regs? or is planning permission needed? I dont care much about a slightly lowered cop if thats the reason) Two more thoughts have occurred to me in the last week - 1. See to the right of the house, there's a window and a door at the back fo the garage? there's radiators inside the extension and in that garage. Do monobloc-type ASHP's mean there only connection to the house is via the central heating circuit itself, all the pumps and diverters are in the external unit and it could go there/ attach to the central heating pipework (possibly)? 2. Simplification. Maybe I shouldn't worry about the DHW via ASHP. I read somewhere to heat 100L of water from 10 to 60 degrees requires about 6kWh. If that is correct(?) could I just heat DHW from octopus cheap night rates using a newer cylinder.. if its really only 200l / 2 x 6kwh x 5p, (c. 60p per day in winter) would that be a decent compromise in your view? ie DHW - excess solar in summer, elec only in winter off a cheap rate.. and ASHP for space heating only? The tank could stay upstairs a mixergy or some other solution just for DHW. Thanks again for your responses!. Really appreciated. And very clear in your rejection of sunamp etc. iain

Hi! I'm sorry for not replying earlier, the notification I thought I had set - didnt thank you for your comments - I shall gather some info and will reply in next days. I believe the heat loss was calculated, I'll search. Yes I expect a number of the radiators will need to be changed. I had expected the elec usage to increase quite a lot. I am sure we throw a lot of heat straight out of the window, literally - warm downstairs, but everyone wants it cool upstairs and the upstairs windows seem open an awful lot of the time in winter. We will probably add some kind of air recircuation upstairs - off topic now but when we lived in canada the house had just that and no opening windows for 6 months of the year, so we need fix that here. We are fully aware of behavoural changes we will need to make. thanks again!

Hi Long term lurker, finally subscribed. Hoping some of the experts could please give some advice, I seem to be at a pause with an ambition to cut our households' CO2. Help! Context: the house is a 1960's 4 bed detached (was 3 bed, expanded with a side extension 2012) and like so many houses of it's type is close to its neighbour, which is 1.4meter away. We own the gap between our house and their solid wall, closed off with a fence at one end. There's a gas central heating boiler downstairs that vents into the gap, and a separate hot water tank upstairs. 3kw of solar panels on the roof. Last month about 70 KWh of that was diverted into hot water immersion so our summer gas usage is minimal. Obviously through winter that diversion won't happen. Last years elec usage was 5000kwh and gas 15000kwh. I have a new EPC, which is a C. I had applied to be part of an OVO ASHP /Sunamp (or hot water store) trial, BUT their assessors said the the house wasn't suitable, with nowhere to put the external pump, as regs forbid within 1m of neighbour, nor at rear (not permitted under window) and couldn't be freestanding at the other side in side garden /next to the garage as the extension has a suspended concrete floor too far away from existing boiler location. Also they'd have to deal with the garage being in the way (solid floor) and run pipes around the outside of the house, then lift kitchen floor, etc etc etc etc. Please see exciting attachments with layout. 'B' = boiler location. 'No' = under window. The existing boiler 'B' is where we'd prefer inside components to be - if possible, as its where the existing plumbing is. See the 1.4m gap between us and next house. The objective is to a) make best use of the solar b) get rid of gas entirely and its co2 c) ideally, take advantage of ASHP financial incentives. I had thought heat storage for DHW and an ASHP was viable. But is it! This is where I'd like please to ask advice and sort out the facts! Several questions. 1. is using ASHP to provide space heating and a water tank heat store, for DHW, viable? 2. if an ASHP is possible, where could you put it? 3. if in the gap is possible, which model/ thickness would fit that gap and pass 'regs' ? 4. is a sunamp a cost /viable option to provide space heating (and possibly DHW?) 5. how would you do it! cheers in advance for any thoughts or options. iain