Home energy saving tips /ideas...

[rogerzilla]

How much would the insulation have saved if you'd kept a gas boiler, though?  And what is the payback period after subtracting the insulation benefits?

My guess is (a) most of the savings and therefore (b) it never pays back.

Of course, there are other excellent reasons to fit a heat pump, but economics aren't one of them.  Unless gas gets a lot more expensive relative to anbaric fluid.

[Quisling]

How much would the insulation have saved if you'd kept a gas boiler, though?  And what is the payback period after subtracting the insulation benefits?

My guess is (a) most of the savings and therefore (b) it never pays back.

Of course, there are other excellent reasons to fit a heat pump, but economics aren't one of them.  Unless gas gets a lot more expensive relative to anbaric fluid.

The Gubbishment has committed* to gradually rebalancing the taxation between gas and electricity to reflect respective emissions.  This is already happening via the Climate Change Levy on commercial bills, but is not yet really being seen on residential tariffs....because there are 29m homes connected to the gas grid and it would take a bold government to stick 29m households straight into deep fuel poverty.

Of course, "economics aren't one of them" is a matter of timescale.  When natural gas runs out, as it will, this statement will no longer be true.

(*because they always follow through right )

[HTFB]

How much would the insulation have saved if you'd kept a gas boiler, though?  And what is the payback period after subtracting the insulation benefits?

My guess is (a) most of the savings and therefore (b) it never pays back.

Of course, there are other excellent reasons to fit a heat pump, but economics aren't one of them.  Unless gas gets a lot more expensive relative to anbaric fluid.

We haven't attempted to break it out. The entire heating system had to be replaced anyway -- the whole house had to be gutted -- so the counterfactual of installing a new boiler into the otherwise heat-pump ready building would be absurd.

The HP unit we got is currently sold for £3,500, against a non-combi boiler at about £1,500, and you can make this difference back just by avoiding the gas standing charge over the unit's lifetime. But of course labour and the rest of the system are the most of it. The government paid £7,500 under the Boiler Upgrade Scheme so if you draw a circle around the right bits of our budget the heat pump made us an instant profit.

[Arminius]

Just to report, before winter ends, that after our first six weeks living with a heat pump we are wonderfully warm and snug, the hot water is hot, and our all-in COP is above 4.5. So we are saving money daily relative to a gas boiler, even before covering a third of the electricity with solar PV.

Admittedly the house is now so well insulated and draughtproofed that we stay entirely ignorant of the temperature outside until we open a door -- the windows never need to open because of the MVHR -- so it's not a very hard test of the ASHP.

We started the project in the brief window between Putin and Truss when energy was expensive enough, and mortgages cheap enough, that it would cover its costs. Alas that didn't last, though in the long run we are happy to bet on gas getting pricier. Still, we're saving a huge amount of energy.

(I've not looked very far back in the thread, so apologies if you've already talked about it...)

Is there anything you can share about what insulation you've put in, what MVHR you used (& if you considered PIV), etc? We want to install an ASHP, though that's not going to be worth doing until we build our extension, but I'd like to hear some real-world experience of MVHR, etc. We already have some solar PV thanks to the previous owners, but I feel there's loads that we can still do. (1970s brick built semi 3 bed with some really odd venting/radiator position choices.)

[Mrs Pingu]

I too would like to see more of your project, HTFB.

[Wowbagger]

We had a chap come to look at our boiler a couple of weeks ago. I had a natter to him as he worked and he reckoned that under current rules & regs we couldn't have an air-source heat pump fitted because we are within 3 miles of the sea and they are very susceptible to damage from salty air.

I haven't bothered to check that but it sounds to be like a load of bolleaux.

[FifeingEejit]

on the basis there are many houses with them in port Charlotte on islay, it definitley sounds like bollocks.

Sent from my IV2201 using Tapatalk

[Kim]

We had a chap come to look at our boiler a couple of weeks ago. I had a natter to him as he worked and he reckoned that under current rules & regs we couldn't have an air-source heat pump fitted because we are within 3 miles of the sea and they are very susceptible to damage from salty air.

I can't imagine it would be against TEH RULEZ to install one (are there any rules, over and above the electrical ones that would apply to installing, say, an extractor fan?), though I could understand the government deciding not to subsidise them.

[Flite]

Our ASHP certainly haven't stood up to the weather in the N. Pennines.
Factor in huge maintenance costs when they go wrong, and nobody wants to service them because they are making too much money with new installations.
Also factor in the replacement costs in 10 years time, on which there will not be a subsidy.

Expensive lesson - we will not be early adopters for any future technology.

[Jaded]

ASHPs need those scummy *ankers in power to stump up the money.

[Arminius]

Our ASHP certainly haven't stood up to the weather in the N. Pennines.
Factor in huge maintenance costs when they go wrong, and nobody wants to service them because they are making too much money with new installations.
Also factor in the replacement costs in 10 years time, on which there will not be a subsidy.

Expensive lesson - we will not be early adopters for any future technology.

Oh, I'm sorry to hear that, that sounds really stressful for you.

Do you know what it is that's caused the problems? Wind? Rain? Cold? Faulty installation? A combination? I hope you have an easier time of it from now on.

We are lucky, I suppose, in that we won't be able to afford to build the extension for another 5 years or so, by which time ASHP technology will hopefully have improved further and there will be more of a market for repair/replacement. I'm still keen to get a good overview of what is possible now, what the issues are, etc so I can implement smaller improvements that will take us closer to our ideal house.

[mrcharly-YHT]

We had a chap come to look at our boiler a couple of weeks ago. I had a natter to him as he worked and he reckoned that under current rules & regs we couldn't have an air-source heat pump fitted because we are within 3 miles of the sea and they are very susceptible to damage from salty air.

I haven't bothered to check that but it sounds to be like a load of bolleaux.

Complete and utter b*llks.

Every new build around here (within 100s of metres of sea) has an ASHP.

[rogerzilla]

I'd look at a GSHP if we bought a suitable property and it had a knackered oil boiler.  I see a lot of houses with an acre or two of paddock which would save a borehole.  GSHPs are generally competitive with gas or oil from the off, although a lot more expensive to install.  There's also no noisy fan or vulnerable outdoor bits.

[Flite]

Do you know what it is that's caused the problems?

They were installed by a Mitsubishi approved company who were endorsed by the council.
The firm stopped trading a few years later, when the grants were less favourable, leaving us with no backup.
A plumbing company based 50 miles away, with no experience of heat pumps, took over the maintenance list.
I suspect the installation was never done properly, and getting even a basic yearly service has been a battle.
Every plumber/electrician/odd bod who looks at it finds something else wrong.
Mitsubishi would take no responsibility.

I reckon snow gets blown into the cabinets and corrodes everything.
We have had 3 master boards replaced (about £1000 a pop, but Mitsubishi did do one for free after I threatened to take them to trading standards for selling a product not fit for purpose). And repeated bills for call out charges and repairs (bodges)

Mitsubishi did a recent temporary fix which cost us several hundred pound, and the engineer (who does try to help) said the units only had a ten year life and would need replacing when they failed again.
But new units are not backward compatible with our plumbing and control systems, so the whole lot will need ripping out and replacing.
Of course, no subsidy for replacements....

Apart from the cost, the toll on our resilience has been massive.

[JellyLegs]

Do you know what it is that's caused the problems?

But new units are not backward compatible with our plumbing and control systems, so the whole lot will need ripping out and replacing.
Of course, no subsidy for replacements....

Identical experience here.  Mitsubishi ASHP was brilliant for almost the whole 10 years we had it but when it failed we found to our cost that absolutely nothing in Mitsubishi’s current product range was compatible with our install.  Our quote for a replacement was over £10k as we needed to have all the old electronic magical wizardry ripped out, scrapped and replaced as well as some re-wiring and re plumbing done.  No grant or subsidy available so we saved ourselves 4k and reinstalled an oil boiler and tank.  Unfortunately imho Mitsubishi have sold all their early adopters right down the river.  I do wonder whether part of the reason nothing is backward compatible is that they had a major issue with the master board electrickery - you had 3 replacements, we had 1 replacement but in reality 2 as they did several component swap outs before they gave up and just replaced the whole thing.  Fortunately we got that done under guarantee having logged lots of overheat error codes almost from install.

[Quisling]

We had a chap come to look at our boiler a couple of weeks ago. I had a natter to him as he worked and he reckoned that under current rules & regs we couldn't have an air-source heat pump fitted because we are within 3 miles of the sea and they are very susceptible to damage from salty air.

I haven't bothered to check that but it sounds to be like a load of bolleaux.

The lifespan of a standard ASHP would be reduced by the increased corrosion rate on the coils. However, you can get ones with treated coils (corrosion resistant coating of some kind). I know Portsmouth naval base has installed a load of heat pumps. Choice may be more limited but there is definitely a solution.

[HTFB]

10 years is not a great lifetime for what is basically a fridge without the yellowing plastic box. The industry reckons they last 20, in commercial use (as lots of them are and have been for ages) with proper servicing, and DESNZ assumes 20 for domestic ASHP too. But then we used to have a Mitsubishi dehumidifier in the flat which didn't last many years either. It's possible they're just crap.

[Flite]

Unfortunately imho Mitsubishi have sold all their early adopters right down the river

Sadly I have to agree.
No-one mentioned the life span of the units -we assumed it would be a lot more than 10 years.
It was a costly mistake that has caused us grief for ten years of what should have been a comfortable retirement.
I have no confidence that all the ASHP now being installed will not have similar problems in the future.

[Quisling]

Unfortunately imho Mitsubishi have sold all their early adopters right down the river

Sadly I have to agree.
No-one mentioned the life span of the units -we assumed it would be a lot more than 10 years.
It was a costly mistake that has caused us grief for ten years of what should have been a comfortable retirement.
I have no confidence that all the ASHP now being installed will not have similar problems in the future.

In comparison, a quick search of "domestic gas boiler lifespan" suggests modern domestic gas boilers are at best 10-15 year lifespan.  Given the significant electronics on board, mean time to first failure is usually significantly lower. Notwithstanding the above, I agree that an ASHP is potentially a more complex beast, although other geographic markets seem to manage issues better - due largely I suspect to a far more skilled workforce.

I installed a wood pellet boiler with support from the RHI in 2013. It's still going strong(ish) after 10 years, and likely to last another 10.  However, the annual maintenance costs are horrific, just for the regular service without any breakdowns. And the flue is rotting out, so that's not a decent alternative to gas either!  At the time, heat pumps just weren't sophisticated enough, but if I was replacing it tomorrow I'd almost certainly go for a heat pump rather than revert to fossil fuels.

[rogerzilla]

Gas boilers used to last far longer than 15 years but condensing boilers have a somewhat harder life.  British Gas, being bastards, also claim boilers need replacing when they don't, because "part M14A-345" is no longer available.  It often turns out to be a generic 6mm bolt or something that never wears out, like the outer casing.

[HTFB]

For policy modelling the best-fit assumption on the data is that the remaining old non-condensing system gas or oil boilers will never wear out. My colleague Roger was trying, with far more effort than the question deserved, to resolve this in 2018. He retired before getting a better answer, and presumably before any of the boilers did.

[JellyLegs]

Unfortunately imho Mitsubishi have sold all their early adopters right down the river

Sadly I have to agree.
No-one mentioned the life span of the units -we assumed it would be a lot more than 10 years.
It was a costly mistake that has caused us grief for ten years of what should have been a comfortable retirement.
I have no confidence that all the ASHP now being installed will not have similar problems in the future.

In comparison, a quick search of "domestic gas boiler lifespan" suggests modern domestic gas boilers are at best 10-15 year lifespan.  Given the significant electronics on board, mean time to first failure is usually significantly lower. Notwithstanding the above, I agree that an ASHP is potentially a more complex beast, although other geographic markets seem to manage issues better - due largely I suspect to a far more skilled workforce.

I installed a wood pellet boiler with support from the RHI in 2013. It's still going strong(ish) after 10 years, and likely to last another 10.  However, the annual maintenance costs are horrific, just for the regular service without any breakdowns. And the flue is rotting out, so that's not a decent alternative to gas either!  At the time, heat pumps just weren't sophisticated enough, but if I was replacing it tomorrow I'd almost certainly go for a heat pump rather than revert to fossil fuels.

I don’t expect my oil boiler to last more than 10 years, but I can replace that for <£3k at the moment.  I want to be green, but I can’t afford the risk of having to stump up an additional £7k every decade or so.  It’s slightly more complicated than that as the oil boiler is undoubtedly more expensive to run.  Current estimate is that the extra running costs over its lifetime will eat up all the savings made on installation but although it is painful, it is easier to find an extra £40ish a month rather than shelling out an additional £7k at time unknown.

[mrcharly-YHT]

I know little about ASHP.
I know a bit about central heating systems (I've repaired my own gas combi, installed a oil central heating system in its entirety)

What confuses me is the statement

new units are not backward compatible with our plumbing and control systems, so the whole lot will need ripping out and replacing.

the plumbing should be simple - unless the Mitsubishi unit was doing something 'interesting' with a heat store. I looked at some diagrams and they just have a out and return, nothing different from, say, an oil boiler'

The control units - why the heck aren't these ASHP just working off a 'call for heat/call for hot water'?

Quite honestly, Flite, I wish I lived near you. I'd love to take a look and try to work out what is so mucked-up with the Mitsubishi design.

[Mr Larrington]

If it’s any consolation, Lt. Col. Larrington (retd.) was also an early adopter and his first Samsung died on its arse after ~ 10 years too.

[HTFB]

The control units - why the heck aren't these ASHP just working off a 'call for heat/call for hot water'?

It's not like a gas burner where either the flame is lit or it isn't, though: as its efficiency is so closely tied to the temperature difference it creates, the control needs to modulate the system output to match heat demand without cycling on and off, rather than just throwing heat into the pipes. New installations use weather compensation, so the output is set by an outdoor thermometer which estimates the requirement from a preprogrammed heat curve.  And the unit has at least two pumps to coordinate, for the refrigerant and the primary water circuit. The whole setup is unavoidably fiddly.