You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Friend lives in an old house with a solid fuel stove that runs the central heating, and no insulation other than in the attic floor. Just about the worst setup possible efficiency wise and environmentally, but simple.
They've had the place assessed and been offered a government grant which would install a heat pump, new radiators and piping, solar panels, and cavity wall insulation - supposedly worth about £50k installed. Now I'm sure that's quite inflated like everything grant funded, and a fair bit of it will be labour, but the technology bits (pump and panel) that have a lifespan and could go wrong must make up over £20k of it.
That seems to me like a lot of scarily expensive kit to be responsible for once the warranty ends. Especially for someone low paid. Say part of it breaks in 5 years, they won't have multiple months' salary to hand they can just chuck at it. And their current system would have been removed as part of the install.
They already got hit quite a few years back with grant funded blown insulation which caused damp problems. They had to get that removed themselves as the installing company and gov grant scheme were long disappeared by the time the issue was diagnosed. The one being offered this time is different and shouldn't have the same problem. But the responsibility aspect is presumably the same again for the insulation and heating kit - once it's installed and a few years pass, it's your problem now.
Also the environmental benefit angle won't register here as they're not at that level of luxury in life. If it works the same or better, costs the same or less to run, and is more convenient then it's good. They're almost flattered I'd say at such a generous offer, but also cautious. Maybe you can get insurance cover like you can for boilers.
Thoughts?
Heatpumps the only thing that would concern me.
The rest is fairly benign with minimal moving parts. Yes parts will need replaced over time but not lockstock whole system.
And most of it has. payback that is beyond expected life span.
The repairs are likely less than the cost of. Buying and maintaining the alternative sans grant.
Oh and I'd run a mile from any retrofit cavity wall insulation. External insulation or internal but cavity wall is just asking for trouble.
So they’ve had cavity wall insulation previously to the point they had to pay to have it removed and they’re now considering more cavity insulation?
It is a source of concern. As I said, it's a different material which claims to be better - polystyrene beads rather than blown foamy wool.
Not sure if the offer is all or nothing, or even if it would even work well enough if you don't do the insulation.
The repairs are likely less than the cost of. Buying and maintaining the alternative sans grant.
There's no need to buy anything to replace the current system, and the only maintenance cost of that is the chimney sweep.
Oh and I’d run a mile from any retrofit cavity wall insulation. External insulation or internal but cavity wall is just asking for trouble.
Noted. External would't fit in with adjoining houses. Internal could do but grant doesn't fund redecoration.
Are they in an area with air quality regulations or that is likely to become one in future? If so, ‘replace now with grant’ is more compelling as replacing later under pressure could be expensive without grant.
Polystyrene beads will still track water across the cavity and cause damp. Cavity walls were designed to stop water tracking from the outside to the inside, they were not intended as part of the house insulation. Filling is just asking from trouble.
As for things going inventors seem to be prime to failure on the solar panel setup, neighbour had to fork out a grand for a new one. He says he's still in profit from the installation but it's reduced the savings and he had to find the grand (they are retired).
From what you've said I'd be exploring insulation of the inside of the internal walls and better loft insulation before considering anything else.
in an old house with a solid fuel stove that runs the central heating, and no insulation other than in the attic floor. Just about the worst setup possible efficiency wise and environmentally, but simple.
unless they live in Spain, I wouldn’t be going near an air source heat pump for that sort of house. It will cost a bloody fortune in electricity to end up with a cold house.
tell them just to heat the house with £10notes in their current stove for similar effect.
A ground source heat pump would likely offer better efficiency but higher capital cost. But only after they’ve replaced the windows and insulated the house to a very high standard
A new built house here went up in flames because the inverter over-heated.
As far as heat pumps needing maintenance, mine has a 7 year warranty and the installer told me it doesn’t really need servicing apart from keeping it clean, clear of leaves etc. Certainly a lot less than a gas boiler.
As said, installing a heat pump in a draughty, poorly insulated house is probably a waste of money.
I'd figure out what can be done in terms of insulation first and foremost. Not having to heat the house in the first pace will be a lot cheaper than any other solutions.
Solar, it's hard to see what can go wrong with it, it's no more complicated than lots of other electrics already in your house, and will make/save them money. Worst but unlikely case it stops working and they don't fix it.
Heat pumps are getting better all the time, the newest ones can run at hotter temperatures than an average gas combi so don't need a full re-plumb with new rads etc although the same principles apply that if you do fit larger rads then the system is more efficient as it doesn't need to run so hot. And heat pump + solar will hedge their bets on energy prices, if electricity prices go up then they're insulated from that effect as even if it's not very efficient in mid winter, they're also generating electricity to run it / sell to the grid.
We had cavity wall insulation blown in a couple of years ago under a government grant, it's made a massive difference. The house used to be freezing overnight, when the heating went off at 8pm it'd be uncomfortably cold by the time you went to bed at 10:30, and the heating being on in the morning wasn't enough to make the house comfortable before we'd left for work.
Now it's on all day at 17.5C 5:30am-8pm due to the OH not working, it barely drops overnight, the house feels warm all night, and despite the rises in the price of gas our DD is currently lower than it was 2 years ago (and we're in credit).
And zero damp.
It depends on the house though. It requires the outer wall / grouting / guttering to be in good condition and not exposed to prolonged driving rain or other sources of damp.
A new built house here went up in flames because the inverter over-heated.
relevance is? House fires can be caused by many items
Hopefully the sums have been done but I'd be surprised if CWI alone would be enough insulation for a ASHP system.
A new built house here went up in flames because the inverter over-heated.
And was that a MCS accredited installer with an approved inverter.
Because either it wasn't the inverter specifically or it wasn't an uk regs approved inverter.
Much more likely a sub standard mc4 connector as that seems to be one of the leading causes of "solar" fires
A heat pump doesn't need a well insulated house. It will need radiators or underfloor correctly sized including pipework.
If your building needs 20kW to heat it it doesn't matter if it is gas, oil, ASHP, biomass or £10 notes that delivers those 20kW. What does matter is how you deliver it and how control it.
If gas is 3 times cheaper than electricity then if you achieve a COP of 3-4 (relatively easy to do if design is correct) then running costs should be similar regardless of insulation.
A well insulated house will be cheaper to heat regardless of how it is delivered.
I would never recommend running a heat pump at higher temperatures to avoid radiator upgrades, that will lower your COP and increase running costs. This is why people think you can't heat old properties with heat pumps because if you don't do the upgrades then you will get a luke warm house that is costing lots to run. The lower you can get the flow temperature the better. Remember all work for a heat pump install is currently zero rated for VAT so spending a bit more on even bigger rads to get that temp down even more makes sense.
Whether it is worth spending thousands on possible radiator and system upgrades is a different matter, however all new, and fully replaced heating systems have to be designed with a maximum flow of 55 deg. C now so you've already got to get most of the way to towards achieving the radiator sizes required by a heat pump.
We have heat pumps running in a castle, that's about as old as you can get!
As for wall insulation, I would speak to a reputable chartered surveyor, but from speaking to guys who do wall tie replacement they say the wall ties that are in the best condition are usually those with polystyrene bead fill rather than anything else.
Bear - Your COP of 3-4 may be correct for the south of England or somewhere it rarely drops near or below freezing.
For those of us in location where it does drop below freezing, your COP when it's cold will be <2 or at least twice as expensive as running gas Central Heating. It's not something that you can design away; its inbuilt to the thermodynamic laws; any Temperature / Entropy chart for the refrigerant used in the heat pump will show with same findings when it gets cold.
Heating a castle with an air source heat pump sounds bonkers!
It’s a ground source admittedly but still low temp.
Vaillant quote SCOP of above 4 at 40 deg flow at -5 externally for their units, output is lower and this is manufacturers figures not real world but those figures are recognised by MCS.
Get the flow low enough and you could achieve 4, use of large buffers, time of use tariffs can all impact running costs.
To blanket claim they don’t work in old buildings or only work in modern well insulated buildings is simply not true.
Also it is a SCOP, you have to look at the whole year. Granted in depths of winter it will be poor but I don’t expect it to be below freezing for the entire heating season.
In the south of England or somewhere else mild, ASHP are probably an OK proposition. For other parts of the country, unless coupled to a modern and highly thermally efficient home are a v.poor choice and a chunk of the population will likely feel scammed once they’ve had an ASHP installed and ran it for a few years. <br /><br />
Using a better source of low grade heat to supply the heat pump should be the second order of importance after insulation when designing your heat pump system; either from ground source bore hole / horizontal slinky or taking low grade heat from the sewer network / ground water where available. <br />
Scruff - do you work in the industry? I think you are probably far cleverer than me!
Fabric first should always be encouraged however I would dispute your assumptions and I suspect that there are many companies who could provide evidence that heat pumps do work in non super insulated buildings in areas north of Watford or as us southerners call it the north!
Yeah, guilty as charged.
Such as the world we live in, I’m quite sure there will be companies promising the world up to and including a happy ending
Heat pumps will almost certainly be a major way of heating our homes in the coming years, but Air Source unlikely to be best method for a large swathe of the country and existing housing stock
They are up against thermodynamic first principles and using the air for the low grade heat supply for an ASHP, the COP plummets as the temperature drops; precisely as you need it most.
They will still of course heat a cave if you wanted to, but might not exactly be the most efficient or cost effective method for doing so.
The headlong rush to installing them is likely to lead to folk feeling understandably swindled when their bills rise significantly
A heat pump doesn’t need a well insulated house
I've seen set ups that didn't work affordably, there was very little insulation (stone built).
Scruff and Bear I think I’d be keen on your consultancy as to whether we do our house!!! 🤓
re the OP. Super tricky one this, solar I think probably a strong bet. ASHP I’m having enough trouble working out whether our mid-00’s well insulated stone build (cavity with insulated breeze blocks and 15-28mm pipe) will work so we can get off oil heating.