ASHP & triple glazing

[Joeboy]

Thanks for posting Joeboy that's a really inpressive performance especially when compared to last years figures and so useful to know for future reference. Good to see Fintray's figures and other suggestions accompanying as well.
Having gone down the path of A2A and been very happy with it I had wondered if A2W systems were worth all the additional expense and upgrades to rads etc so it's great to learn of use cases where results are so positive.

I would think folk who have the heating covered by A2A would be able to use a ASHP hot water cylinder to provide the DHW at a fraction of the cost of a full system? You could duct it to use house air in winter and external air in summer to make it as efficient as practicable?

I’m still wondering about something similar myself as we appear to need very minimal heat but with a family of small boys and large dogs the DHW demand seems to be fairly high. High enough for me to be attempting to model our DHW consumption over winter to add to the house data for overall energy use.

Moxi

I'll watch the developments on the A2A's with interest. Might get for No1's smaller home.

AD, glad you enjoyed the post. Just wanted to sprinkle some real world positivity for those reading up on AP's. Hope to assist in nudging folk from thinking about it to getting the quotes in!

I continue to have minor data errors on the oem side of things when a hot dhw cycle is running. In real terms it might distort the scop figure over time but not enough that I'm bothered. Continuing to tweak the dhw flow rate to see if we can dial in a sweetspot.

As to the A2A's, the two we have in Turkey are excellent. Never missed a beat and the older unit has been in for seven years now.

[Stinsy]

I would think folk who have the heating covered by A2A would be able to use a ASHP hot water cylinder to provide the DHW at a fraction of the cost of a full system? You could duct it to use house air in winter and external air in summer to make it as efficient as practicable?

I’m still wondering about something similar myself as we appear to need very minimal heat but with a family of small boys and large dogs the DHW demand seems to be fairly high. High enough for me to be attempting to model our DHW consumption over winter to add to the house data for overall energy use.

Moxi

I’ve looked at these. However (similar to DHW thanks that plumb into a multi-split) they’re bordering on “vapourware”.

I’m yet to find an actual person, IRL or online, who has one in their house. They tend to be very bulky and expensive with poor efficiency (official claims in the 2.75 CoP range), and they require complex an expensive ducting (particularly if you’re installing it in an old airing cupboard in the middle of a British house.

They’re clearly designed for the American market where they can pay their way doing double duty as a dehumidifier for the basement and where the cold air can be exhausted into the house to save in AC.

Currently I heat my house with the single A2A on the upstairs landing and resistive heaters in the kitchen/living room. This is only possible because I can reliably game additional cheap slots anytime I need them.

The 30yo 30kW gas combi still does DHW. I plan to swap the gas boiler for a cylinder this year. I might plumb a Willis heater and circulation pump into the CH circuit to see how that does next winter.

Down the line I’ll plumb a small HP (maybe 4-6kW) into the CH and cylinder. I’m on 10mm microbore, which isn’t HP friendly in theory but I’m working on the assumption that 14x rads will provide suitable emitter power and flow…

[Adokforme]

Thanks for posting Joeboy that's a really inpressive performance especially when compared to last years figures and so useful to know for future reference. Good to see Fintray's figures and other suggestions accompanying as well.
Having gone down the path of A2A and been very happy with it I had wondered if A2W systems were worth all the additional expense and upgrades to rads etc so it's great to learn of use cases where results are so positive.

I would think folk who have the heating covered by A2A would be able to use a ASHP hot water cylinder to provide the DHW at a fraction of the cost of a full system? You could duct it to use house air in winter and external air in summer to make it as efficient as practicable?

I’m still wondering about something similar myself as we appear to need very minimal heat but with a family of small boys and large dogs the DHW demand seems to be fairly high. High enough for me to be attempting to model our DHW consumption over winter to add to the house data for overall energy use.

Moxi

That sure will be interesting to see how your figures stack up Maxi and if you do progress to a conclusion the journey taken to arrive there.
For just the two of us with DHW covered by an abundance of pv for 8 months of the year then dear Octopus's 7p overnight rate and storage batts keep figures acceptable if not absolute minimum. It was only that we had so much energy being exported in the early days of the system that I installed a
210 litre thermal store to consume rather than "waste" quite so much to export. For sure without excess pv it probably wouldn't make sense especially with the attractive 15p/kWh export rate on offer these days.
Just checking back on our DHW figures for this year to 1st Dec then we've paid for 571 kWh's at 7p, so £40 near as damn it. To date I haven't yet lost too much sleep.

[Adokforme]

I'll watch the developments on the A2A's with interest. Might get for No1's smaller home.

AD, glad you enjoyed the post. Just wanted to sprinkle some real world positivity for those reading up on AP's. Hope to assist in nudging folk from thinking about it to getting the quotes in!

I continue to have minor data errors on the oem side of things when a hot dhw cycle is running. In real terms it might distort the scop figure over time but not enough that I'm bothered. Continuing to tweak the dhw flow rate to see if we can dial in a sweetspot.

As to the A2A's, the two we have in Turkey are excellent. Never missed a beat and the older unit has been in for seven years now.

On the smaller homes front then this last year I had a 3.5 kW A2A system installed in my sisters bungalow to cover space heating combined with a single electric rad in shower room. DHW being covered by a 10kW electric shower with a single similar unit for kitchen and bathroom sinks. The first months consumption figure was very impressive so I'm anxious to discover if the second months proves similar. When I have this to hand I'll perhaps go into more detail about the whole project.
Good to learn of seven years trouble free service Joeboy as ours has been in six years now.
Our friendly installer was telling me of a system he had installed and called to replace a few weeks prior to Christmas. On checking it out he serviced, re gassed it and told the owner to save his money or book a holiday. It was installed 30 years ago and he knows of many he's installed with similar longevity!

[Moxi]

Everyone will have their particular requirements and be starting from different positions but I think the common aspect is that heat pumps work. I agree with Stinsy that the CoP for the tank integrated heat pumps is a lot less than that achieved by a standard ASHP but the difference in cost and space may make that a moot point for some. Equally some folk might be happy to use a standard hot water cylinder and immersion heater combined with cheap rate electric/ free pv generation if they already have it and change to a mother option when equipment becomes dated / unreliable.

JB and Fintray are showing us what very well designed systems can achieve along with indicative costs. Somewhere between these systems and the standard cylinder and immersion system is where people will end up depending on funds, existing infrastructure and preferences.

For is my wife is erring towards a heat pump and using our wet rads as she likes the idea of even temperature around the home, for me I’m thinking that an A2A system would provide the same even heating for less outlay with the bonus of cooling capacity on the occasion that we get a warm summer here abouts. That then leaves the DHW issue which could by by various options but I clearly need a hot water cylinder so for a few hundred quid extra maybe a heat pump gives me. 2.75 multiple- more if the system uses house air at 20 degrees and exhausts outside and the A2A fills in the 20 degrees air at its cop of 3 to 3.5 ? It’s all in the mix and waiting on data and agreement for marital harmony but the common thread remains the fact that heat pumps work.

Moxi

[Joeboy]

Everyone will have their particular requirements and be starting from different positions but I think the common aspect is that heat pumps work. I agree with Stinsy that the CoP for the tank integrated heat pumps is a lot less than that achieved by a standard ASHP but the difference in cost and space may make that a moot point for some. Equally some folk might be happy to use a standard hot water cylinder and immersion heater combined with cheap rate electric/ free pv generation if they already have it and change to a mother option when equipment becomes dated / unreliable.

JB and Fintray are showing us what very well designed systems can achieve along with indicative costs. Somewhere between these systems and the standard cylinder and immersion system is where people will end up depending on funds, existing infrastructure and preferences.

For is my wife is erring towards a heat pump and using our wet rads as she likes the idea of even temperature around the home, for me I’m thinking that an A2A system would provide the same even heating for less outlay with the bonus of cooling capacity on the occasion that we get a warm summer here abouts. That then leaves the DHW issue which could by by various options but I clearly need a hot water cylinder so for a few hundred quid extra maybe a heat pump gives me. 2.75 multiple- more if the system uses house air at 20 degrees and exhausts outside and the A2A fills in the 20 degrees air at its cop of 3 to 3.5 ? It’s all in the mix and waiting on data and agreement for marital harmony but the common thread remains the fact that heat pumps work.

Moxi

There is maybe the view that the space heating multiplier on the a2a offsets a fair whack of the 1:1 downside for immersion heating?

I am looking at our bigger picture now. A2a multiplier plus export allowed me to step away from Ripple, invest that returned money at 5% which then allows me to top up the Octopus account if the export in good months doesn't quite cover it? Sorry to go off track but the a2w multiplier gave me the ability to reshape my RE world to a closer to home more satisfying setting. It might do similar for all?

[Moxi]

Absolutely JB heat pump multiplier’s work at many levels and you can get into the multiplier at varying costs to work your way up towards the “gold standard” of a well designed home system.

As an example we have a mobile air conditioning unit that we bought to keep the dogs cool during the long hot summer a few years back. It’s been in the wardrobe for around 18 months because it’s seldom that hot where I live but I was reading Resy’s A2A posts again recently and it made me go upstairs to check our mobile system and sure enough it also heats so after Christmas on suitable days it will be coming out to trial heating the house, I managed a quick run with it before Christmas and my wife was impressed with the heating capacity even after a short run.

For me this is a “free” heat pump source that I can use to save some cash and prove the concept to others before progressing to the next stage.

I reckon the next stage being “ can we dispense with the ad hoc mobile cables and ducts but keep the heat “

At that stage it’s going to be a discussion about the various options and heating and cooling vs heating and DHW all stacked against the fact that for us at least we need to fit it into an 84 sq meter cottage with the kids and the dogs.

I doubt we will be able to go gold standard here just because we would need to gut the cottage to do ALM the plumbing but I will be happy to aim for bronze or silver until the kids are grown up.

Moxi

[Ronski]

Moxi, those portable air conditioning units are flawed, unless they are the twin hose system. The ones with just the exhaust effectively suck the air out of the room, and if you do that air needs to come back in from somewhere. Most have a single exhaust designed to be vented outside, and thus a lot of air that needs to be replaced. I used to have one in the office at work, and when switched on you could literally hear the walls creak as they were sucked in.

[Moxi]

It’s not really a flaw it’s a limitation of the design which has to be a compromise on the split system, the compromise or inefficiency is reflected in these systems COP which is less than the equivalent split system.

The exhaust air draws a depression in the house and increases infiltration air, the air infiltrating needs to be warmer than the exhaust air for the COP to be positive.

The best way to prove the concept for us will be to pop the air conditioner outside on cooling cycle with the exhaust vent fed into the house via the cat flap - that way it will operate to strip heat from the outside air and eliminate infiltration air by dint of over pressure on the discharge side of the circuit. Just need a suitable cold dry day or a big rain cover for the unit.

It’s not proposed as a long term solution just a proof of concept for the family and to make use of something in the interim that would otherwise be sat taking up space and depreciating.

Moxi

[Joeboy]

Liking the reverse thinking Moxi! I hope the test day is soon.

Here's a few encouraging graphs

Before ashp


A wee bit ashp with home temp equalise ongoing


Equalised and normal operation


As above but one day missing (today), includes daughterly & No1 abusing the hell out of us over Christmas!


If I hit the full 7p charging per night and don't touch the grid during the day then that's worth £23 a week to us going on pre/post ashp figures. I don't want to run the sums without ashp or on a normal tarriff as it would be scary. Some 150-mile ev charges in amongst it all, quite evenly spaced.