air to air heat pumps work

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air to air heat pumps work
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Nicky cigreen

Joined: 25 Jun 2007
Posts: 9967
Location: Devon, uk

Posted: Fri May 30, 25 4:13 pm Post subject:

Slim wrote:

..... If you can't make it work then that's a you problem at this point

I imagine properties are quite different comparing USA to UK - What is the housing stock like there? how are they constructed? I believe they are going in new housing here, certainly I think new houses should be built with the requirements for ASHP, but the problem is converting older houses - and we have lots. Also we tend to have housing with little or no outside space, and everyone is closer together.

dpack

Joined: 02 Jul 2005
Posts: 44405
Location: yes

Posted: Fri May 30, 25 4:28 pm Post subject:

re usa vs uk properties, both are very varied , the variations are from age , design, price band, etc

outside cities the us ones tend to have more space

re low energy input in the uk, i worked next to and on a scandahaus in the 1980's

in winter a few twigs took it from cool and unoccupied for 5 days to warm in 20 mins, triple insulated, heat exchange chimney, ducted warm air heating for background etc

plenty of space for PV for that one, and it is in a hundred acre wood

i have also known uk houses that are only cosy if you burn a 1/2cwt of coal a week

they were built for that

in the us outside of cities there is a lot more scope for carbon reduced energy than in cities or in most uk rural properties

Slim

Joined: 05 Mar 2006
Posts: 6709
Location: New England (In the US of A)

Posted: Fri May 30, 25 9:38 pm Post subject:

The UK housing stock clearly needs better/more/any insulation anyway, it's kind of a separate issue. Improving insulation reduces energy use and therefore climate impact of whatever system, and is typically a better return on investment than most other spending.

My own home is common for 25 year old house. Stick built, 2x6 walls, with only fiberglass. I've improved the attic insulation here, probably a foot and a half of rock wool batts.
Nicer homes were built much better than this.
My father's house is WWI era. Practically no insulation (and some unique characteristics that make adding insulation very impractical). If he switched to a hybrid boiler he would be burning less oil, and producing fewer climate impacting emissions. Why not incentivize that switch when his boiler is aging out?

I don't see why any of this is a bad idea to reduce climate impacting emissions?

Get the folks to jump for solar and insulation and a heat pump if you can. Get the test to jump for insulation if you can. Get the remainder to reduce their fossil fuel consumption with a hybrid system if you can. None of that is mutually exclusive or "all or nothing" beyond the specifics of any one specific incentive

Mistress Rose

Joined: 21 Jul 2011
Posts: 16508

Posted: Sat May 31, 25 6:53 am Post subject:

I would agree with that Slim, and I think that is the answer Ty Gwyn. If you can't get people to go the whole hog, which is difficult, get them to reduce where they can. Insulating parts of our house would be very disruptive, but putting in solar panels a lot less so. I should add our house started life as 2 railway carriages about the time Slim's fathers house was built, and has carried on from there. We still have the original chimneys, but the rest is 'interesting'. SIL always seems to end up in the bathroom rather than at the front door.

gz

Joined: 23 Jan 2009
Posts: 9247
Location: Ayrshire, Scotland

Posted: Sat May 31, 25 6:48 pm Post subject:
The problem with all the schemes that turn up is that every time they seem to be "one size fits all" and each latest idea is the best thing out...ignoring the fact that houses and people are all different.

Mistress Rose

Joined: 21 Jul 2011
Posts: 16508

Posted: Sun Jun 01, 25 7:44 am Post subject:
That is true Gz, and not just for this sort of thing.

gz

Joined: 23 Jan 2009
Posts: 9247
Location: Ayrshire, Scotland

Posted: Sun Jun 01, 25 7:50 am Post subject:
Playing politics instead of getting the job done

dpack

Joined: 02 Jul 2005
Posts: 44405
Location: yes

Posted: Sun Jun 01, 25 9:58 am Post subject:

imho heat pumps are ace if you have ground or water to source from

ground water is extra good if the water moves

specific heat capacity of water vs air, no contest

take a degree C out of a cu M of each and the energy harvest is several factors of ten different

similar issues to wind turbine vs shetland array water turbine, umm on that one, i rather like the shetland array, scaled up it would be a reliable, predictable energy harvest at a reasonable cost per MW

wind is cute and tested at scale,it sort of works
but air is three noughts short of water for kinetic energy for volume and velocity
ie a hurricane might knock you over, a small river or tidal flow at knee ht often does

iirc air is three noughts short of water for latent heat

Nicky cigreen

Joined: 25 Jun 2007
Posts: 9967
Location: Devon, uk

Posted: Sun Jun 01, 25 11:57 am Post subject:

gz wrote:

The problem with all the schemes that turn up is that every time they seem to be "one size fits all" and each latest idea is the best thing out...ignoring the fact that houses and people are all different.

very true

Nicky cigreen

Joined: 25 Jun 2007
Posts: 9967
Location: Devon, uk

Posted: Sun Jun 01, 25 12:10 pm Post subject:

Slim wrote:

The UK housing stock clearly needs better/more/any insulation anyway, it's kind of a separate issue.

I think it is more that we have a LOT of very old housing stock, that don't lend themselves to insulation - My attic is stuffed. I have double glazing. But the ground floors are solid and I looked into trying to insulate them but it is very difficult, digging down will undermine the walls which were built long before proper footings were a thing - and the ceilings are low so it can't go on top. the walls are solid and have no cavity, insulating walls on the inside is considered a bad idea given the construction of this house. It's not that we don't know that insulation is a good idea, but can it be done to the standard needed to make ASHPs work? often not.

Quote:

My father's house is WWI era. Practically no insulation (and some unique characteristics that make adding insulation very impractical). If he switched to a hybrid boiler he would be burning less oil, and producing fewer climate impacting emissions. Why not incentivize that switch when his boiler is aging out?

I don't see why any of this is a bad idea to reduce climate impacting emissions?

Get the folks to jump for solar and insulation and a heat pump if you can. Get the test to jump for insulation if you can. Get the remainder to reduce their fossil fuel consumption with a hybrid system if you can. None of that is mutually exclusive or "all or nothing" beyond the specifics of any one specific incentive

The point, I believe, Ty Gwyn is making is do hybrid systems actually work? - is it ok to have less insulation and a bigger ASHP or more panels, is half boiler half ASHP a good idea or is it a con designed just to claim the gov grants.
I don't know. It seems ASHPs do work, yes, for a house insulated to a certain standard, with certain heating systems within, but do these mix up arrangements work or is it greenwashing? It is worth trying to find out the answer to this question.

Ty Gwyn

Joined: 22 Sep 2010
Posts: 4632
Location: Lampeter

Posted: Sun Jun 01, 25 1:18 pm Post subject:

To be honest i was intrigued when i had the phone call regarding this Hybrid system where the air pump was connected to the oil central heat ing working on a thermostat regarding outside temps but also a manual where i could switch to either,that made the bells in my head ring,i thought let them come and i`ll pick their brains,i had so manyquestions to ask and the 2 sales men/manager on the phone kept telling me the surveyor when he calls will explain it fully to me,

They could`nt give me a specific time for an appointment except between 12 and 3 pm so i found jobs around the farm yard to do,they never turned up,got a phone call the following day saying surveyor called and no answer,i`d already told them there are 12 properties around here with the same postcode but only one John Williams,another appointment was made,and they never turned up again,apparently mix up in the managers diary,they wanted to make another appointment but could`nt give a specific time other than between 12 and 3pm,i told them that was not good enough as there is another company advertising on a local web site and i`ll contact them for a better service to be told a lot of companies are now offering the Hybrid systems.

Tell me,why would a company install solar panels,where i could possibly sell electricity back to the grid,a hybrid heat pump and insulation,costing around Â£20 to 30,000 if i am able to turn it off manually and carry on with the oil,something does`nt ring true.

Mistress Rose

Joined: 21 Jul 2011
Posts: 16508

Posted: Mon Jun 02, 25 7:32 am Post subject:

Sounds as if you are better off without that company Ty Gwyn. Some are just in it to claim the government grants. The trouble is, very few of them will send someone who know what they are really talking about in the early stages, even if you tell them you won't speak to someone that can't answer your questions. If you are interested, you are better speaking to someone local you can trust and will answer any queries you have.

Slim

Joined: 05 Mar 2006
Posts: 6709
Location: New England (In the US of A)

Posted: Sat Jun 07, 25 11:40 am Post subject:

Like everything, there's differences in quality, etc.
Some companies are better than others.
We have two air source heat pumps. The one in our house is a Fujitsu, and while functional and efficient enough, we've learned that their quality is lower, and they're more likely to leak coolant, which is counter to climate goals.
As with many things, you get the quality you pay for...
The second one we had installed in our preschool building (sole source of heat, but we were able to build that thing pretty well, 2x6 walls with rock wool insulation, and something approaching R-70 in the ceiling with all of my layers) is a Mitsubishi and that's what I recommend to anyone I talk to about it.

As mentioned way long ago in this thread, insulation is important, but all heating systems are rated by how many BTU they deliver per hour. All living spaces have a given range of air turnovers per hour, and related amount of BTU per hour needed to keep the space at a given temperature in given weather conditions.
Therefore, insulation helps, but that's true for any heating system. If you're currently keeping it warm enough with what you have, you need to match that BTU per hour capacity, regardless of what heating system you replace it with.

So the insulation argument is related, it helps a lot to reduce heating demand, but ultimately separate from whether or not heat pumps are effective. As long as they're sized properly (and the manufacturer, installers, etc., are of sufficient quality and integrity) then they work.

Here's the new model I'd prefer to use, for my own heating budget, though I'm not sure it's the best for climate concerns: https://xkcd.com/3099/

Nicky cigreen

Joined: 25 Jun 2007
Posts: 9967
Location: Devon, uk

Posted: Sat Jun 07, 25 1:26 pm Post subject:

my understanding, and correct me if I am wrong, was that ASHP cost more to run ( than mains gas CH) , and so the big point of insulation was to bring down the running cost.
I think many are discovering that their ASHPs are resulting in higher running costs atm, and that's houses that *have* increased their insulation.

Regarding 'hybrid' systems, I've been researching what other moorland homeowners have put in locally and a few have gone for hybrid systems that are actually different floors - so it could make sense to have heat pump ( ASHP or GSHP ) for the ground floors ( involving the work of digging up the solid floors, insulating, laying underfloor heating and reflooring) and using gas CH for upstairs... lots to think about.

Slim

Joined: 05 Mar 2006
Posts: 6709
Location: New England (In the US of A)

Posted: Sat Jun 07, 25 3:01 pm Post subject:

The dollars per BTU produced will always be in flux as different energy sources follow different market pressures, and depending upon policy impacts on pricing.

Unfettered gas production can make gas much more affordable than most options, but is continuing the release of fossil carbon....
Heat pumps will almost always use less power than pre-existing resistance electric heating....

What happens as gas or electricity become more or less expensive moving forward?

I bought panels while net meeting was, and continues to be, in effect here. Zero incentive for me to do any attempts at battery storage, time my usage for daylight hours, etc. The utilities lobby against this, but they still benefit as I'm sending them more power than I'm using on sunny days when they have the most grid demand for cooling (so those kwh are worth much more) and use the most when the supply is highest, and the kwh I'm using are the cheapest for them to supply. But if the rules get shifted, than my power usage, cost of heating our other building, etc., will shift as well.

Last year I switched to a new offering for heat pump users, charging much less in the winter months, and much higher in the summer months. I mostly only buy in net power in the winter months, so it works out quite well for me. (Too bad they do the net metering only on a kwh basis, not the value of the kwh!) But again, this scheme can be changed in the future, and would shift a $/BTU comparison of energy sources.....

95% of our household heating costs is entirely in our control, however, as it's just the depreciation and maintenance on my chainsaw, wood splitter, wood stove, and my time. I don't know of any other way to future proof against market and policy impacts on the cost of heating beyond cutting your own wood, or possibly making a very large solar system with storage that can be used if needing to go off the grid. And even cutting my own wood on my own land is only so much in my control.... There's the potential for my health to no longer allow it, there's the potential for my property taxes to skyrocket for some reason and force me to sell the land, and the initial costs are not accessible to many, etc.....

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