Crofter Posted June 3, 2023 Share Posted June 3, 2023 A combination of rising electricity prices and the ending of my current tariff (Total Control) means I'm going to have to look at finally overhauling the heating system in my 1970s bungalow. We have no mains gas and if everything else was equal I would prefer to avoid oil. So I guess I'm looking at some form of heat pump. But I don't know a great deal about them. The house is about 90m², three bedrooms although one is tiny. Suspended floor, cold roof. Mixture of 2G and 3G windows. Reasonable loft insulation, cavities filled, underfloor insulation in some rooms. NW Scotland so quite exposed and cold, although we don't get long hard frosts. Currently heated by night storage heaters plus panel heaters, and a UVC for DHW. Also a 4kw woodburner heating the living room. What heating options should I be considering? Wet vs A2A? I'm aware that there are some grants and loans available for ASHP installation, but I presume that would require getting everything done by an accredited installer. Will that wipe out the savings, vs a DIY approach? Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 3, 2023 Share Posted June 3, 2023 Hello, stranger! 5 minutes ago, Crofter said: I'm aware that there are some grants and loans available for ASHP installation, but I presume that would require getting everything done by an accredited installer. Will that wipe out the savings, vs a DIY approach? Yes, as with everything the government are involved with, a complete cake & arse party. Forget it. Better option would be to chase any grant for fabric improvements like insulation (cavity & EWI) and 3G. How infinite is your supply of properly seasoned (20% or less) wood? 2 Link to comment Share on other sites More sharing options...
Crofter Posted June 3, 2023 Author Share Posted June 3, 2023 5 minutes ago, Nickfromwales said: How infinite is your supply of properly seasoned (20% or less) wood? Certainly not infinite! And complicated by the fact that I'm actually renting the house out these days, so it needs to be fairly idiot proof. Link to comment Share on other sites More sharing options...
Nickfromwales Posted June 3, 2023 Share Posted June 3, 2023 11 minutes ago, Crofter said: Certainly not infinite! And complicated by the fact that I'm actually renting the house out these days, so it needs to be fairly idiot proof. If you are renting it, then leave well alone? Link to comment Share on other sites More sharing options...
Crofter Posted June 4, 2023 Author Share Posted June 4, 2023 2 hours ago, Nickfromwales said: If you are renting it, then leave well alone? Holiday let- so I'm still paying the bills! Link to comment Share on other sites More sharing options...
Iceverge Posted June 4, 2023 Share Posted June 4, 2023 Tackle that suspended floor would be the first port of call IMO. Link to comment Share on other sites More sharing options...
JohnMo Posted June 4, 2023 Share Posted June 4, 2023 Can't you just switch to economy 7, electrician to make a few changes to consumer unit - job done. British Gas offered me economy 7 the other week, so it's an available option. Your other options are ASHP, with big radiators run on weather compensation. Multi room a2a heat pump. Both multiple thousand pound options 'v' a couple of hundred for E7. 1 Link to comment Share on other sites More sharing options...
Crofter Posted June 7, 2023 Author Share Posted June 7, 2023 On 03/06/2023 at 21:04, Iceverge said: Tackle that suspended floor would be the first port of call IMO. By 'tackle', do you mean insulate? Link to comment Share on other sites More sharing options...
Iceverge Posted June 7, 2023 Share Posted June 7, 2023 6 minutes ago, Crofter said: By 'tackle', do you mean insulate? Yes. Lift floor boards. Drape a breather membrane between the joists, tape diligently to all walls. Fill with batt insulation. Airtight membrane over the top. Replace floorboards. Don't worry too much about getting extremely low U values. The windtightness (breather membrane) and Airtightness ( airtight membrane) will stop the bulk of the heat losses. 1 Link to comment Share on other sites More sharing options...
Crofter Posted June 7, 2023 Author Share Posted June 7, 2023 On 04/06/2023 at 03:47, JohnMo said: Can't you just switch to economy 7, electrician to make a few changes to consumer unit - job done. British Gas offered me economy 7 the other week, so it's an available option. Your other options are ASHP, with big radiators run on weather compensation. Multi room a2a heat pump. Both multiple thousand pound options 'v' a couple of hundred for E7. I'm happy to invest to get the ongoing running costs down. Switching to E7 would obviously be cheaper in the immediate term, but not a straight swap, because I still need to add timers to each individual heater. Link to comment Share on other sites More sharing options...
Crofter Posted June 7, 2023 Author Share Posted June 7, 2023 46 minutes ago, Iceverge said: Yes. Lift floor boards. Drape a breather membrane between the joists, tape diligently to all walls. Fill with batt insulation. Airtight membrane over the top. Replace floorboards. Don't worry too much about getting extremely low U values. The windtightness (breather membrane) and Airtightness ( airtight membrane) will stop the bulk of the heat losses. I agree, that would be the best solution. A couple of problems though- the house was built with T&G pine boards and they run under all the partition walls. So not a small job to lift. Secondly, I've not long laid laminate through about 50% of the whole area... not keen to take that up again! Fortunately, the access from underneath is reasonably good. Link to comment Share on other sites More sharing options...
IGP Posted June 8, 2023 Share Posted June 8, 2023 16 hours ago, Crofter said: I agree, that would be the best solution. A couple of problems though- the house was built with T&G pine boards and they run under all the partition walls. So not a small job to lift. Secondly, I've not long laid laminate through about 50% of the whole area... not keen to take that up again! Fortunately, the access from underneath is reasonably good. https://www.ecologicalbuildingsystems.com/post/suspended-timber-floor-insulation-installation-underneath ? 1 Link to comment Share on other sites More sharing options...
Crofter Posted June 8, 2023 Author Share Posted June 8, 2023 2 hours ago, IGP said: https://www.ecologicalbuildingsystems.com/post/suspended-timber-floor-insulation-installation-underneath ? That's a great guide, thanks. Any suggestions for where to start on the ASHP/A2A side of things? Link to comment Share on other sites More sharing options...
Crofter Posted June 8, 2023 Author Share Posted June 8, 2023 Just as a starting point, how about something like this: https://www.theheatpumpwarehouse.co.uk/shop/heat-pumps/air-source-heat-pumps/samsung-8kw-r32-monobloc-air-source-heat-pump/ I guess I then need oversized rads, pipework, circulation pump, anything else? On the DHW side, can I just keep my direct UVC and use off peak to heat it overnight? I guess that will cost more to run than switching to a tank supplied by the ASHP, but obviously it's a lot less work and upfront cost. Would be interesting to compare the numbers. I'd like to learn about A2A as well, so that I can compare the two options. Link to comment Share on other sites More sharing options...
RichardL Posted June 8, 2023 Share Posted June 8, 2023 (edited) IMO Quickest way into A2A - google maps - zoom out - search for Air conditioning installer & find one that does residential.. Have them quote and you'll also have a line the sand re equipment and cost... Installers will have their preferred shortlist - at least mine did - and thats your start for googling/diving into manuals etc Some of my 101 learnings: - Mitsubishi electric and Mitsubishi heavy are completely different firms. - They'll prefer to put inside units on external walls. - Mitsu / Panasonic - names you recognise seem to be a better bet than box shifters - but then I wasn't in the market for the box shifting firms. - Think about Power to the outside unit & location - generally you can tap into a ring main - but IMHO preference was for the external units to have their own separate circuit/breaker (just me perhaps?) - POV is different - so installer might not want internal trunking but might care less about external trunking (i.e. commercial that way round makes sense) - residential its a balance - You won't need an inside unit in every room - depending on layout the warm air will move through the house & rise. Be aware by default for residential they seem to default to remote controls - i.e. not central heating style control of the whole house - you can go there but its £££ unless you DIY a bit. After that its so much opinion/discussion.... Edited June 8, 2023 by RichardL 1 Link to comment Share on other sites More sharing options...
Crofter Posted June 8, 2023 Author Share Posted June 8, 2023 I've got a lot to research about A2A. So if I'm understanding right, you don't generally fit a central unit with ducting, but instead fit individual units for each room? I think my house would be suitable for most installations- detached bungalow with suspended floor and cold roof, so good access everywhere. I'm assuming I'll be going DIY with this, I'm reasonably handy once I've got my head round something, and I'm between jobs anyway so I have the time. Against that is the possibility of grants and interest free loans, which I have heard can be up to £15k in Scotland. But I'm assuming that, to be eligible, you have to jump through hoops and it would rule out the DIY approach. Haven't looked in to it yet though. Link to comment Share on other sites More sharing options...
RichardL Posted June 8, 2023 Share Posted June 8, 2023 Ducting would have been perfect for my house (retrofit) - the challenge is access space to get the central unit installed and cost. I didn't have enough loft space to speak of which took it off the table. Certainly an option - especially with the access you have - preferable I guess to have vents vs. inside A2A boxes on the wall. Control is interesting - i think you need to balance the flu's into each room or have a way of baffling them passive and? active - to stop hot spots. (guessing to be honest - I didn't go far down that route) AFAIK you can't get grants for A2A anyway - I just went for it - Personally it was fix leaky pressurised wet system, upgrade rads and marginal heat due to the age of the house fabric etc - or something simpler which can if required give that similar ooomphf of heat which an old boiler can if things get cold. (after insulation EWU and new under tile insulation) Link to comment Share on other sites More sharing options...
TonyT Posted June 8, 2023 Share Posted June 8, 2023 Most domestic would be copper pipes between the internal and external unit, fully insulated with a condensate drain connection. Depending on make and model power is taken to either the outdoor/indoor unit and an isolator is installed then generally a 4 core cable between the units for providing power and communication between the 2 . many have remote control for temp change or you get wall mounted, modern units also can have an app for user control. the outdoor unit is generally pre charged with refrigerant gas, and depending on the distance between the 2 units more gas may be required. Link to comment Share on other sites More sharing options...
Crofter Posted June 8, 2023 Author Share Posted June 8, 2023 So I've done a bit of research on the rads, according to an online calculator based on T30 figures, I'd be spending about £750 on rads. Is T30 a bare minimum? Should I oversize? And on top of that I'm needing pump, maybe a header tank?? Link to comment Share on other sites More sharing options...
sharpener Posted June 9, 2023 Share Posted June 9, 2023 Is that Delta T = 30? Will work with a high temp HP. Delta T = 25 would be better, latest installer I have contacted will not design for flow temp more than 45. For a smallish property the circulating pump in the HP will be sufficient, unless you have a buffer tank which are anyway to be avoided on efficiency grounds. Water circuit will be pressurised so you would need a small expansion tank in a corner not a header tank in the loft. Some mfrs have a complete indoor hydraulic unit designed to go on a kitchen wall like a boiler, but for what they are they are expensive. 1 Link to comment Share on other sites More sharing options...
JohnMo Posted June 9, 2023 Share Posted June 9, 2023 The attached tells you how to work out the sizing of you radiators. HPAI Heat Pump Code of Practice.pdf 1 Link to comment Share on other sites More sharing options...
Crofter Posted June 9, 2023 Author Share Posted June 9, 2023 1 hour ago, JohnMo said: The attached tells you how to work out the sizing of you radiators. HPAI Heat Pump Code of Practice.pdf 4.05 MB · 1 download That's my bedtime reading sorted, thanks! Link to comment Share on other sites More sharing options...
JohnMo Posted June 9, 2023 Share Posted June 9, 2023 No problem. Makes a bit more sense than the MCS guide. Link to comment Share on other sites More sharing options...
Crofter Posted June 9, 2023 Author Share Posted June 9, 2023 I'm just starting to wrap my head around the A2W and A2A options. Very early days. A2A does look temptingly cheap and easy to install! I've done a very rough sketch of the basic layout, then two different A2A installs- one central unit in the hallway, or two units feeding four rooms. For context, the house is currently used mainly as a summer holiday let (although we will be moving back in full time at some point). The smallest bedroom is only used for storage. The bathroom has a small electric towel rail. DHW currently supplied by a direct UVC in the cupboard. The north and east elevations of the house are completely hidden from view and would be by far the best places to put an external ASHP unit. S side may be acceptable but not ideal. 1 Link to comment Share on other sites More sharing options...
RichardL Posted June 20, 2023 Share Posted June 20, 2023 Thoughts: (not necessarily solutions) - Do you need one in the kitchen? - If Bed2 can point towards the door it may heat/cool the hall when the door is open. - If Kitchen can point towards the door it may heat/cool the hall when the door is open - however - see above - if the kitchen doesn't need one & the lounge door is open that may heat the hall too? 1 Link to comment Share on other sites More sharing options...
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