nod Posted January 21, 2021 Share Posted January 21, 2021 With the plots purchase imminent We are starting to plan the house On our first build while knowing little about ASHP I quite fancied moving with the times and installing a heat pump But with gas readily available I was overruled This time I’m reliably informed there is no gas So seems like a no brainer But I still need to sell the idea to my other half I’ve seen that some ASHP can be reversed in summer Is that feasible ? Also my main question Can this system run everything UFH bathrooms etc Percentage wise Comparing supplying and installing ASHP and a traditional system ie gas boiler What would be the differential Also any recommendations as to what system to have installed Bit long winded but thanks in advance Link to comment Share on other sites More sharing options...
ProDave Posted January 21, 2021 Share Posted January 21, 2021 Simple answers yes yes and yes. If you are having all UFH then perfect. An ASHP will heat DHW in an unvented tank, avoid a thermal store, they need water stored hotter than an ASHP is comfortable with. Most of us heat the DHW to about 48 degrees which is plenty hot enough for use but not as hot as a gas boiler would go, so we tend to use a slightly larger HW tank. Don't order the ASHP until you have a proper detailed heat loss calculation so you know it is sized to the size and insulation of the house. they WILL be lower power than a gas boiler so it is important to get the size right. Mitsubishi Ecodan is a popular choice and not over expensive and I have not heard anything bad about them. There is the "discussion" whether to get an MCS install and claim the RHI, which might not be very much for a new install, and might have finished anyway before you get there, or just buy it and get your plumber / electrician to fit it. If you are thinking of using it for cooling, as well as the UFH you might want to consider a couple of Fan Coil Units mounted high in the building to deliver chilled air (just like an AC unit) which is more likely to chill the whole house than just running cool water through the UFH. 1 Link to comment Share on other sites More sharing options...
Temp Posted January 21, 2021 Share Posted January 21, 2021 We have seen a few posts from people with issues with their ASHP. Majority appear to be people with undersized systems, possibly because people are optimistic with their assessment of how well insulated the house is. I'm actually glad we went for an oil boiler because my house isn't as good as I thought it would be. Building Regs have improved since we built ours but I wouldn't build to the current regs - aim for much better. 1 Link to comment Share on other sites More sharing options...
nod Posted January 21, 2021 Author Share Posted January 21, 2021 1 hour ago, ProDave said: Simple answers yes yes and yes. If you are having all UFH then perfect. An ASHP will heat DHW in an unvented tank, avoid a thermal store, they need water stored hotter than an ASHP is comfortable with. Most of us heat the DHW to about 48 degrees which is plenty hot enough for use but not as hot as a gas boiler would go, so we tend to use a slightly larger HW tank. Don't order the ASHP until you have a proper detailed heat loss calculation so you know it is sized to the size and insulation of the house. they WILL be lower power than a gas boiler so it is important to get the size right. Mitsubishi Ecodan is a popular choice and not over expensive and I have not heard anything bad about them. There is the "discussion" whether to get an MCS install and claim the RHI, which might not be very much for a new install, and might have finished anyway before you get there, or just buy it and get your plumber / electrician to fit it. If you are thinking of using it for cooling, as well as the UFH you might want to consider a couple of Fan Coil Units mounted high in the building to deliver chilled air (just like an AC unit) which is more likely to chill the whole house than just running cool water through the UFH. Thanks Dave Can you give me a rough idea of what the difference in cost would be between the two Double treble Just to give me some idea Link to comment Share on other sites More sharing options...
ProDave Posted January 21, 2021 Share Posted January 21, 2021 28 minutes ago, nod said: Thanks Dave Can you give me a rough idea of what the difference in cost would be between the two Double treble Just to give me some idea Not understanding the question? Link to comment Share on other sites More sharing options...
nod Posted January 21, 2021 Author Share Posted January 21, 2021 47 minutes ago, ProDave said: Not understanding the question? I’m just looking for some comparison between installing ASHP and the supply and installation of a gas boiler Link to comment Share on other sites More sharing options...
TonyT Posted January 21, 2021 Share Posted January 21, 2021 If I were starting again and going down the boiler route, I would try to design a small plant room/ utility room where access to pipework is available, i would also ensure 2x100 mm ducts were installed from the gas boiler area to a potential location where an ASHP would live, it would make changing over less hassle. 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted January 21, 2021 Share Posted January 21, 2021 I would guess that ASHP and UFCH will be at least double the price of gas boiler and rads, but if there is no gas, you don't have much choice. 1 Link to comment Share on other sites More sharing options...
nod Posted January 21, 2021 Author Share Posted January 21, 2021 21 minutes ago, Mr Punter said: I would guess that ASHP and UFCH will be at least double the price of gas boiler and rads, but if there is no gas, you don't have much choice. Yep that’s the reason for my question While we will definitely have UFH to the GF Some friends are almost finished with tiger Self build No gas But they have had a gas tank installed in the garden that runs the boiler 44p per liter Which my wife thinks is great But I would rather install ASHP The UFH to ground floor would remain the same and also the rads in the bedroom So really if I was to say £3500 allowed for the boiler and instal Would I be anywhere near if I allowed 10 k for The supply and install of the ASHP Link to comment Share on other sites More sharing options...
ProDave Posted January 21, 2021 Share Posted January 21, 2021 35 minutes ago, nod said: I’m just looking for some comparison between installing ASHP and the supply and installation of a gas boiler ASHP will cost more than a boiler, but probably similar to cost of gas boiler AND gas supply connection. ASHP can be DIY installed if you are competent, gas can't Actual install of ASHP or gas boiler ought to be very similar, the problem is a lot of plumbers and electricians won't touch them because they think they are difficult and ar not prepared to read an instruction manual and learn. The rest of the heating system, UFH, hot water tank etc is the same regardless of heat source. Link to comment Share on other sites More sharing options...
joe90 Posted January 21, 2021 Share Posted January 21, 2021 +1 wot @ProDave said. UFH in a slab is cheap to instal and very easy to DIY. I bought my ASHP on Ebay dead cheap and installed it myself. From what I have read on many threads here the only people with problems boil down to bad design, bad instal, bad set up. I am more than pleased with mine. Link to comment Share on other sites More sharing options...
Trw144 Posted January 21, 2021 Share Posted January 21, 2021 28 minutes ago, joe90 said: +1 wot @ProDave said. UFH in a slab is cheap to instal and very easy to DIY. I bought my ASHP on Ebay dead cheap and installed it myself. From what I have read on many threads here the only people with problems boil down to bad design, bad instal, bad set up. I am more than pleased with mine. What sort of COP are you achieving (and what electric tariff)? Link to comment Share on other sites More sharing options...
joe90 Posted January 21, 2021 Share Posted January 21, 2021 3 minutes ago, Trw144 said: What sort of COP are you achieving (and what electric tariff)? To be honest I don’t know but I have only seen it defrost once in over a year of working. I don’t have any measuring kit (well @SteamyTea has some kit here but I don’t know what it’s measuring etc). I am on Octopus variable rate, pay per month on usage. When I get my ass in gear I need to work out if it’s worth going E7 so may need to talk to @SteamyTea about what measuring kit I need. Link to comment Share on other sites More sharing options...
nod Posted January 21, 2021 Author Share Posted January 21, 2021 48 minutes ago, ProDave said: ASHP will cost more than a boiler, but probably similar to cost of gas boiler AND gas supply connection. ASHP can be DIY installed if you are competent, gas can't Actual install of ASHP or gas boiler ought to be very similar, the problem is a lot of plumbers and electricians won't touch them because they think they are difficult and ar not prepared to read an instruction manual and learn. The rest of the heating system, UFH, hot water tank etc is the same regardless of heat source. None of the site plumbers and gas fitters have any experience of ASHP Though I suspect very soon all this will change Link to comment Share on other sites More sharing options...
ProDave Posted January 21, 2021 Share Posted January 21, 2021 Just now, nod said: None of the site plumbers and gas fitters have any experience of ASHP Though I suspect very soon all this will change A monoblock ASHP is just flow and return just like a system boiler, and some motorised valves and a pump or 2. Read the Flippin Manual. I don't know why so many people treat it as witch craft. 1 Link to comment Share on other sites More sharing options...
Mr Punter Posted January 21, 2021 Share Posted January 21, 2021 1 hour ago, nod said: Would I be anywhere near if I allowed 10 k for The supply and install of the ASHP Yes. The units are a lot more than gas boilers but if your house is well insulated that seem like a decent budget. Depends on cylinders, controls etc where you will need a bit more say £15k. If this is a spec development you are wanting to turn you may want to think twice. The gas tanks are like being a hostage. Probably the ASHP would be half the price to run but purchasers don't look at this (unless they have one). 1 Link to comment Share on other sites More sharing options...
nod Posted January 21, 2021 Author Share Posted January 21, 2021 6 minutes ago, Mr Punter said: Yes. The units are a lot more than gas boilers but if your house is well insulated that seem like a decent budget. Depends on cylinders, controls etc where you will need a bit more say £15k. If this is a spec development you are wanting to turn you may want to think twice. The gas tanks are like being a hostage. Probably the ASHP would be half the price to run but purchasers don't look at this (unless they have one). Thanks That’s helpful Link to comment Share on other sites More sharing options...
nod Posted January 21, 2021 Author Share Posted January 21, 2021 29 minutes ago, ProDave said: A monoblock ASHP is just flow and return just like a system boiler, and some motorised valves and a pump or 2. Read the Flippin Manual. I don't know why so many people treat it as witch craft. I think it’s more opportunity Though more builders are starting to use air pumps Link to comment Share on other sites More sharing options...
SteamyTea Posted January 21, 2021 Share Posted January 21, 2021 (edited) 1 hour ago, joe90 said: I don’t have any measuring kit (well @SteamyTea has some kit here but I don’t know what it’s measuring etc I shall see if I have the old spreadsheet I did a couple of summers back. This lockdown is good, means I don't have to 'cross the border, under the cover of darkness' to get into Devon to see you. But come the spring, we should be alright. Here we go. Blue columns are the complete year, red line is the winter, Dec, Jan and Feb. You could possibly benefit financially, but when you look at your absolute numbers, they are pretty low. Edited January 21, 2021 by SteamyTea 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 21, 2021 Share Posted January 21, 2021 (edited) And here are the means for @joe90's Your loft is amazingly stable. Edited January 21, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
joe90 Posted January 21, 2021 Share Posted January 21, 2021 (edited) 39 minutes ago, SteamyTea said: Your loft is amazingly stable. It’s a warm roof ? and the whole house is that stable (thermal mass ?) (but I have no idea what the figures mean ?♂️) but the graph looks good ? Edited January 21, 2021 by joe90 Link to comment Share on other sites More sharing options...
SteamyTea Posted January 22, 2021 Share Posted January 22, 2021 @joe90 Basically, as ~45% of your usage is fixed load i.e. MVHR and Sewage Treatment, which cannot be time shifted, and your ASHP loads are small, peaking at 70% extra (in winter), and as you know, you don't have the heating on for long, there is nothing to be gained by swapping to E7 as you generally need to shift 80% of your load to the 7 hour window. E10, if you can get it (I can't) may offer a slight financial advantage, but it is pennies, not pounds. Really down to finding the overall cheapest price. 1 Link to comment Share on other sites More sharing options...
Pete Posted January 22, 2021 Share Posted January 22, 2021 13 hours ago, nod said: None of the site plumbers and gas fitters have any experience of ASHP Though I suspect very soon all this will change I have fitted my own ASHP with the help of a plumber (and buildhub) and it has cost me around £6000. I had quotes of £12/13000 and nearly choked on my porridge! My £6000 was for a brand new 9kw Panasonic Aquarea with HW cylinder and associated valve and pipework. I put my own heating pipes in the slab and kept it all one zone and it works great. It has taken me two/three weeks to understand how to run it and how it interacts with my house but now I am getting the hang of it ( thanks to @joe90, @jackand @ProDavefor giving me advice on their setups). My advice is do your homework and KISS like most have on here. Like Dave said treat it like a boiler and your plumber will have no reason not to be able to fit it. My Panasonoc came with a simple schematic to explain the setup and the controller is really easy to use. I am only up the road from you if you want to see my system. 1 3 Link to comment Share on other sites More sharing options...
nod Posted January 22, 2021 Author Share Posted January 22, 2021 Thank you everyone for all the info While I fitted out the plumbing on ours With the exception of the boiler and commissioning which was done by a friend BM After reading all the above I feel confident that I will be able to install an ASHP system With Dave’s advise ringing in my ears Read the Bloody instructions ? Probably m ok re a man thing than a plumbing thing Great starting point Thanks again 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now