Hybrid Air-Source heating

Yes but the efficiency off them is not good at that temp range, if i remember right they say a 17% saving over gas.
Most air source heat pumps running at the 34 degree temp are well into the high 300 % and almost 400% efficiency, but once you increase the flow temp the efficiency soons drop off, thats the reason most air source heat pumps only heat the water in a cylinder to 50 degrees

About 9 years ago we replaced the softwood double glazed windows and doors of the original build (self build finished 1990) with Internorm triple glazed units. They have powder coated aluminium externally on wooded frames. The chalet is about 300m2 so quite large. We don’t heat the four guest bedrooms except for family visits. We have no painting inside or out now, and have saved a lot on heating. It’s been a good investment as well as delivering visual satisfaction. I couldn’t live with uPVC windows!

The gas component of our £110/month energy bill is less than the electric even in winter. Probably 40% this month.

As I mentioned very early on insulation is the key to a low carbon future. If you are embarking on buying a cottage to improve, get an expert to advise. @Dunc is spot on.

Phil

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My sister has a state of the art , expensive air/air system in her luxury bungalow

It’s always cold when I go round!

Not something I would go for.

Yes the noise can be a problem in quiet rural environments… I am aware of a few issues locally, and one where the heat exchanger had to be relocated.
I believe some of the newer more expensive exchangers are more quiet, but there is consideration of reflective services, concrete floors, brick walls than can reflect and channel the sound. You can also use acoustic baffles around the exchanger in quiet locations, without affecting efficiency too much apparently. I am told in a typical urban or suburban environment with general background noise of traffic etc, it’s not an issue at all.
Best have it on a wall ideally with no windows facing away from any neighbours… but anyway it can’t be near or under a bedroom window from a planning reg perspective… as when the window is slightly open, as many bedroom windows are for much of the year, it would be audible at night.
on some new housing developments, where everyone has an exchanger it must be less of an issue… my daughter has such an arrangement in a small village, but it took her a while to get used to the background noise… but she came from a very quiet house and location.

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The ecodan is very quite, in fact it’s called whisper quite.
Triple glazing should be just compulsory on any new window, this would help slash the price for them.
The biggest problem with air source is prolonged cold weather, as when the temperature falls outside the out put falls on the unit, it can go from being a 11kw to a 9 kW, not so bad if it’s only for a few days and you have underfloor heating, you probably won’t even notice, but if we start getting weeks of cold weather, by that I mean, -5 and below then most folk with air source heat pumps are knackered or should I say cold

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Ours is a not based on meter readings and the payment is fixed based on assumed energy use / output (calculated on basis of the energy performance certificate that had to be done for the application). There is a meter, but it is for monitoring only and not calculating payments.

Yes tim thats how it was, but not anymore, can’t remember when it changed but its been a few years now

I did point out that with weather compensation LTHW flow will only be running at 75C at morning startup or during very cold weather. With climate we have in the UK they will be running at 55C or below for the majority of the time.

The calorifier is only heated up to approx 55C for safety reasons. Although the controls probabley allow for an anti legionalla cycle which will involve heating to approx 70C.

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Its not quite the same as a heat pump really, but still a nice bit of kit, especially if no mains gas.
But a saving of just 17% a year, isn’t really a game changer and i bet it costs quite a bit more than say a gas boiler?
But this sort of technology needs to keep on going and get better, as we need units that can run at high temps, say 70 degrees, but also be very efficient, because most homes in this country, an air source heat pump is no good.
I also guess we need to make alot more electric as if not its a waste of time if it wont switch on

Yes indeed - fibreglass frames would be good, too, sadly hard to get and therefore expensive.
We have full triple triple glazing, in aluminium clad timber frames. The amazing thing is we get condensation on the outside on cold mornings, because the outer pane to all intents and purposes don’t get any heat from inside at all, so they behave like the glass or metal of an unoccupied car. Whole-house heat recovery ventilation also means none of those stupid trickle vents needed in windows. It means we never need open windows in winter - and with their better soundproofing I suppose that would make the noise of air source heat pump less of an issue (but any noise issue is an issue - as with SiS, we live in a very quiet place).

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Snap! But different brand. I don’t recall the name offhand, made in Germany though UK agent. Back in 2011 they were pretty hard to find - and didn’t seem to have improved much when I looked last summer thinking of the next house.

I guess one doesn’t need to, but I am assuming most prefer to if they can… there is no substitute for sleeping with a small flow of fresh air with the occasional sound of wild life … even when very cold outside it seems to not be an issue, it’s only when blowing a gale or storm do we shut as it is then too noisy.

Mrs SinS and I do struggle in some modern hotels which are centrally air exchange ventilated where windows can’t be opened … it can be very hard to sleep soundly… perhaps its just what you are used to.

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100% :slight_smile:

Winter or summer we always have a bedroom window open… even just an inch.

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Reading these replies, and very helpful thanks, the priority is insulation. This strikes me a bit like EV cars. To make the cars go further they’re built using super modern light/strong materials and designed to cut through the air better. I often wonder if they applied the same efficiency technology to normal ICE cars then what effect would that have on your mpg?

So if you line the walls, triple glazing, top the loft up, super lagged tank, &c., then what does that do to your heating bill even if you don’t go air-source?

What I need to decide, assuming we can/don’t go the underfloor heating route and go hybrid, is this worth doing? I still do the various insulation/window/tank things anyway. If you’re gutting a house and also having all the first floor windows to replace then it makes sense to do these things.

btw… a spanner in the works we will have a wood burning stove BUT I might find a way to pipe an external air feed.

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I like the sounds (done some reading as well) of the Ecodan. From what I can see this is just a supplementary hot water tank for hot water. Is that hot water only? Why not just put a supplementary heating loop in your standard water tank?

The thing about the while house ventilation is that it doesn’t get stuffy at all - there is no ‘bedroom smell’ as you get from a closed unventilated room in the morning, and we very quickly just found that it was so comfortable that nothing makes us want the windows open, when any odd external noise like a passing car or barking dog of crowing make chicken (apparently I’m not allowed to name it!) waking us, or excessive draught when the wind picks up in the night - but visitors do often open the windows because they are used to those things and are conditioned to an open window.

As for hotel rooms, I find British ones often are too hot for comfortable sleep, with controls set so you can’t reduce adequately…

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A very interesting thread.
Our house has an oil boiler which my wife and I are looking to replace and was looking air or ground heat source. We also have an outdoor pool with pool house that has another oil boiler as well so we were looking to change that first and see how we get on. We have had a couple of people round and a “darth vader” seems to be the popular choice of air source. There are downsides though as it can’t heat the water for the shower in the pool house or the hot water in the kitchen so that means we will have to get an electric boiler of some kind, or maybe gas cylinders. All this has put us off a bit and after reading this with the noise (that was not mentioned to us) it is starting to feel like the hurdles are maybe a bit too high at the moment which is a shame.

The point to note is that it works best if the house is designed and constructed to be a passive house. There are then other possibilities for thermal storage/heating. Grand Designs has explored the options over the years. The most adventurous was a large earth bank forming part of the house heated in summer and drawn upon in winter. The owner was naturally anxious whether he had done the calculations correctly!

Phil

In my view building regs should be changed to require all new construction to be to passive house standards. If that was done the price differential from the materials and methods would fall so as to be very small or negligible as a proportion of overall house cost. But huge training requirement for an industry traditionally rather resistant to change.

Interestingly I went to an exhibition of low energy homes in Milton Keynes, with lots of novel ideas including thermal stores (whatever happened to the idea of a eutectic store that could effectively store a much greater amount of heat energy per unit volume?), and I remember being struck by the benefit of a heat pump. I just googled to remind myself when it was: 40 years ago this year! And only now are some of the ideas becoming mainstream.

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I can’t remember the numbers but we lived in a rented house half the size of our current one while ours was being built and with the insulation being massively better our oil and electricity bills dropped significantly in the new house compared to the rented one. I forgot to mention that we have a mechanical heat recovery ventilation system so can get fresh air in the house at 90% efficiency - if zero outside and 20 inside, the fresh air coming in is warmed to 18 degrees - without having windows open. The air in the house always feels perfectly fresh

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