Earth Notes: KEHS talk: My Home Heat Pump Installation (2025)

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Twelve years ago I had that chap called Ed Davey, who happened to be the Energy Secretary

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at the time, standing in my living room, proudly telling him that I'd put enough solar on my roof

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that I would be able to cover our electricity all the year round and we basically wouldn't have

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much energy bills, whatever, but we'd be carbon neutral. And I achieved it ... on the 29th of November

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last year. So it took 12 years from getting ready to getting through, because [the] Renewable

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Heat Incentive didn't work right. And even if we take a slightly less harsh view, when I applied

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to Octopus for a quote, I think it was in April of last year and it took until November,

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And I had to really push, and because we don't turn our heating on until December,

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that was just in time. So I have a strong view, which I'm about to write in an open letter to the

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Secretary of State and to Greg of Octopus, that it ought to be possible for most people to put it

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in two days. And even in a distress purchase in the middle of winter, you're not just tempted to

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slap another gas boiler on the wall. So does it work? Is it saving? Was it quick? So here was my

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simple answer. Yes, yes. NO! 12 years, a bit slow. Does it work? Yes. So it went in on the 28th

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actually, it was officially commissioned on the 29th, and we've been warm and had hot water and

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stuff since then. Now they managed to install it with some interesting faults. So I spent quite

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a lot of time fighting it to start with, but absent those faults, it's been fine. We have not

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had no hot water. We have not been cold. I mean, I've been tweaking with the settings. So if you

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ask my other half, she might have a slightly different view, but that's one, that's an arguable one.

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So it does its job.  It did take two months to diagnose a fairly major installation fault.  On the other hand, the system was robust that it ran for two months with a fairly major installation

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fault. [] So Octopus came and did some sums. They didn't really pay attention to the insulation works I'd done and so they came out with a figure for heat loss and thus the the size of a heat pump we need which I said "That's out by a factor of two [] at least."  Being the sad git that I am I have half-hour gas readings

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through the coldest days we ever had in this house. So I can tell you exactly what we ... anyway,

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they're not allowed to take that into consideration, but they went and did their sums again and said "Oh yes, you're so right!" So in the end we only swapped out one radiator, and actually I should have let them

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put a slightly bigger one in [there]. But the really peculiar thing, the outside unit doesn't make any [noise] ... 

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It's like having an oscillating fan [whoosh, whoosh] noise; when it's getting really flat out it's like [WHOOSH]...

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But it's not, you know, it's not a horrible noise, not a whine or anything. The really odd thing is that

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where the pump comes in from outside, the hot and cold water coming from outside,

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and the cylinder is right behind our living room wall. And the living room radiator is right on the

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other side of it. So it basically gets first dibs on any hot water coming in, which meant that this

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heat pump circulation, you need a lot more water moving around your system, a lot faster for a heat

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pump than you do for a gas boiler. And this is all getting piled through my poor little radiator.

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And the noise being made by this radiator, I mean, you know [SSSSH] , to the extent that, you know,

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the family's having to turn the TV up to hear over it. And so it took what it turns out that when

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the fault went away, they'd fixed the fault, I was able to reduce that. And now it's just like it was

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before, effectively. There are some very slight oddities like because it's running, it's actual

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water outside, running from outside in the external unit, there's no anti-freeze in it. When the

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temperature drops to close to zero, six degrees or below, it circulates the water and runs the

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compressor a little bit to stop it freezing, which means that at four in the night or something, you

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can hear [sssssh] noise. But it's not bad. It's fine. It's actually no worse than any, it's fine. It's a

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fairly nice heating system. But it did take some messing around - took me two months to solve that and I was on the point of writing to Octopus and saying "This is broken, this system. If no one can

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hear the TV, it's not working." We also are doing an unusual thing. So as I say, heat pump installers

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want you to have all of your radiators on or open all of the time, and all the rooms at the same

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temperature. NO! I mean, it's certainly the case that people sleep more comfortably in cooler rooms.

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And, you know, when you like us one of your kids has left home, why are you still heating their room? And stuff like that. If you have an absolutely bang-up-to-date Passive House you barely need to

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heat it anyway. So I'm with a heat pump installers at this moment. But my formal research shows you

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can have TRVs like the ones that are on the end of these radiators with 1-2-3-4-5 and very easily reduce

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the heat demand in rooms that you want to be cooler, save energy, save the planet faster, save money.

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So has it been saving? So it went in just at the end of November. So ignoring that for each of the

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following months, December, January, February, March, April, which we've had bills in for, that bill has

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been lower than the corresponding month last year, even though all of those, this month, other than April,

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were colder than the same one last year. So it's been colder outside and our bills have been lower.

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It's slightly cheating because I was doing complicated [stuff] with our systems before.

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But this energy bill for this whole of the last month was 20 quid. And most of

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that is standing charge. So that's we've got the PV and so on. But the heat pump was much better

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with the battery than I thought it would - with my electrical battery. So I expanded it a little bit last month - I bought a second-hand unit.  Our carbon footprint if you look this is

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our graph of our carbon [footprint] from gas and electricity since then. So you can see we made

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some effort. We started at six tons.  So here I assumed a fixed carbon intensity, how much carbon

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was emitted for every kilowatt hour generated - standard figure up until there. And then I changed

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to a SUPER (possibly!) accurate version where every hour I measure our actual whether we are importing or exporting

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and what the grid intensity is. So it makes that very little difference. But maybe it said we went

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slightly positive. I think we'll get come down and go negative again. And I had an idea yesterday

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in the bath as one does - I can knock another 10% off. So the cost [that] Octopus originally quoted

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as two thousand seven hundred in the end, I think partially to get rid of me, partially because I only

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wanted one radiator change, was two thousand five hundred. Octopus' target has been to get it down

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cheap enough that it's actually free. They are trying to make it possible to have no CAPEX and

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no OPEX (no bills). That's their target. Realistically, if you go to someone like Leah of Your Energy,

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Your Way, she'll tell you she can't get anywhere near Octopus because they're throwing a huge

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invisible subsidy in on top of the government. But a few thousand quid, which is roughly what it takes

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to put a new combi in - a condensing combi - is what you can expect. I mean, that grant is designed to

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make it no more painful than than putting a new gas boiler in, except for the disruption involved.

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Was it quick? Well, as I say, depending on how you measure it, there's the last time I had a

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Secretary of State for Energy in my house. I'm sure it happens to you all the time.

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And I had colour in my hair - and it was 12 years. That's when I wanted to do it. So I would have

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been slightly behind Peter, but not much, in putting one in. I think getting in the queue,

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there aren't enough installers around. So you can't just phone up and have it done instantly.

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There are more works to be done. In this open letter to the Secretary of State and so on I'm going to say

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"This is how I think you could make it happen in two days for most installations." If it costs the same as

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a gas boiler, costs the same to run as a gas boiler as well, and you can do it in two days, why wouldn't

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you put in a heat pump, unless you believe the Daily Mail horror stories that it's going to make your

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children go trans or something - I don't know. Should be two days. So, space taken. So we had the

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the thing on the left, we had the combi boiler in here before, and I have a heat battery as well, which is sitting down here... If we didn't have the heat battery we'd just about - just about - have

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got the hot water tank inside there, we could have stayed in roughly in the same space -

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we'd have lost some cupboard space. All that needs to be in the house these days is a hot water tank.

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The reason we all loved combis is they were instant hot water,

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which never runs out. You didn't need hot water tank. And so people's airing cupboards got, you know,

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recovered for other purposes. So you need to have one back with a heat pump. However,

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I've got a heat battery. We've got a water tank. You can see the top of the thing sticking out of the

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top here. This is our replacement. You put all the gubbins inside. And if you go right back to the

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front [page], that is the thing outside, which is about the size of a moped. And I took this

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picture because it's interesting because it was just frosting up. So an interesting thing that

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happens in the UK is you spend a lot of time with the temperature just above zero and quite a lot

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of humidity in the air. And so you get frost on the fins and the system has to do a defrost cycle.

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It's quite spectacular. It's a plume of steam coming out of the thing. It's quite spectacular.

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You don't get that with the old boiler. It should be that if you have a boiler which fails

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in December, you're going to say, could you please repair it, or can I have like-for-like?

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Because you understand that. It took me 12 years or eight months or two months or whatever it is,

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to get mine in. And I had to do a lot of external works. So we've got to get over this. I wrote 22,000

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words on the process. [] When you've got a gas boiler,

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you've basically got two controls that you can touch. One is the temperature your radiators run at,

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and one is the temperature your hot water runs at. My heat pump's got something like 50 parameters.

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Now you don't normally get to see all of them. And I am doing PhD, and I've looked,

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but I've written 7,000 words on all the changes I've made to those parameters. And the aim of my

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research, which is improving home heating decarbonisation, so we can actually do it properly,

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is how can we make it as simple as [possible] - people didn't run their gas boilers properly - we have

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to make it simpler than running a gas boiler, and less disruptive, and no more expensive. And I

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believe all of those things can be done without huge changes to the way people are working.

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We just need to think about it very differently.