Air Sourced heat pump

[nicholab]

Has anyone switch to a Air Source heat pump? What has your experience been?

[elsiegee40]

I don’t know if this is paywalled, but this article is from Which? .

 

https://www.which.co.uk/reviews/ground-and-air-source-heat-pumps/article/air-source-heat-pumps-explained-al5MC4f773Zq

[chazzy2501]

I looked at these and they look promising. Unfortunately they don't add much value to the home and will takes years to pay themselves back. if you don't plan to move for 15 years then they'll be a cost benefit.

 

(very rough summary with oodles of assumptions)

[Theblacksheep]

Insulate as much as possible, especially the loft, but pay attention to rubber seals on doors/windows and those cold spots you know about. You do need a minimum EPC rating to be able to get on the government scheme so double glazed windows, led bulbs, loft insulation and cavity wall all help older properties reach that minimum.

 

Get your radiators first, lower temps (45-55) mean you need larger surface areas to heat up the spaces. All are double thick rads now. Insulate the flow and return pipes to make sure you maximise the heat to the rads.

 

Ensure your outside unit has enough airflow around it.

 

You will probably need space for a water cylinder, it cannot boil on the fly like a combi. Consider one that can take a solar heater, that way if you have solar or get some in the future, you get some free water heating. 180 litre tank might be enough hot water for 2 adults + 1 child per day.

 

If you have land, consider a ground source heat pump. They are more expensive, but you get paid more for them, are cheaper to run they are more consistent.

 

Smart controllers essential, if the water takes 30-45 mins to get to temp, you want this done based on intelligently.

 

US info online will mostly be air/air heatpumps, UK mostly has air/water, so careful of that. Air/air does not qualify for the RHI either. Another gotcha is that if you like 24c heat (looking at you wife) then ASHP will be expensive to run than gas.

 

Switch to a cheaper energy supplier, with eco7 (or smart) you want to be generating your hot water for 5p per kwh, not 20p. I've used Bulb and Octopus recently, I've switched to Octopus Go (15p/5p and 100% green), DM me up if you want £50 off your switch with a referral.

 

 

If I was doing it again, I wouldn't have installed underfloor heating and gone for more rads straight away. It was expensive, but I get paid £60 a month for 7 years, so it does get offset a bit.

Edited May 19, 2021 by Theblacksheep

[jmak]

Nearly....

 

Deposit paid, installation next month. Advice from experience so far:

 

Find a few companies who've done something similar before - we live in a Victorian house, so it's quite a different prospect to installing in a modern house and I wanted to see evidence of happy customers with warm houses! I hope that's going to pay off.

 

Budget for radiators. I'd planned to replace ours anyway and had a ballpark figure in my head based on like for like swaps. (I'd also intended fitting them myself, but firstly some of them with over 100kg and secondly as they're specialist items there's not much saving to be made.) What we're ending up with is 25% of the total cost. Some of the radiators are huge - with prices to match.

 

On the up side, our house is so inefficient and the system is so expensive, we'll get the maximum grant... Hoping that over 10 years it'll be cost neutral compared to replacing our >40 year old oil boiler, which was the alternative. Installer is more optimistic, but I'd rather be pleasantly surprised.

[Michael]

I haven't bought one, but I have looked into it. There are two aspects to look at (very much like electric cars really).

 

1. Is it better for the environment (possibly).

 

2. Are you better off financially, probably not, far from it.

 

An Air Source Heat Pump requires space in your garden, as well as a water cylinder in a cupboard/garage, which ironically a lot of people in the UK got rid of in favour of a Combi Boiler.

 

An Air Source Heat Pump will continuously turn a motor (which of course uses electric) to generate heat and heat your water cylinder.

 

So as it stands, your gas is roughly 2-3p per Kw and electric can be as much as 14p per Kw - all I can suggest is look at your current tariffs with your energy supplier.

 

Personally I think the future will be hydrogen, as the existing pipe network serving gas could be used for hydrogen and manufacturers of gas boilers (such as Worcester Bosch), now sell dual gas/hydrogen boilers in preparation. It'd work in the same/similar fashion, burning on demand when you turn the tap on and not continuously. The biggest issue in the UK from what I've read, is it's currently expensive to manufacture hydrogen, but I'm sure that will change.

 

The biggest issue I have with all this - Air Source Heat Pumps and electric cars, is if everyone did this, would the national grid cope? I've no idea, plus there are questions on how all this additional electric would be generated?

 

So there you have it - still unfavourable cost wise and still questions environmentally. Everything just doesn't add up at the moment.

[mavhc]

If the layout of the house would work easily I'd look into HVAC, going to need cooling more than heating in the future, and heating air with a reversible heat pump is much easier than heating water, then pumping it to radiators, and having that heat the air.

[supportman]

Does anyone have some companies to look for? I've got a big garden to so hoping to do the ground sourced pump.

[jmak]

I haven't bought one, but I have looked into it. There are two aspects to look at (very much like electric cars really).

 

1. Is it better for the environment (possibly).

 

2. Are you better off financially, probably not, far from it.

 

An Air Source Heat Pump requires space in your garden, as well as a water cylinder in a cupboard/garage, which ironically a lot of people in the UK got rid of in favour of a Combi Boiler.

 

An Air Source Heat Pump will continuously turn a motor (which of course uses electric) to generate heat and heat your water cylinder.

 

So as it stands, your gas is roughly 2-3p per Kw and electric can be as much as 14p per Kw - all I can suggest is look at your current tariffs with your energy supplier.

 

Personally I think the future will be hydrogen, as the existing pipe network serving gas could be used for hydrogen and manufacturers of gas boilers (such as Worcester Bosch), now sell dual gas/hydrogen boilers in preparation. It'd work in the same/similar fashion, burning on demand when you turn the tap on and not continuously. The biggest issue in the UK from what I've read, is it's currently expensive to manufacture hydrogen, but I'm sure that will change.

 

The biggest issue I have with all this - Air Source Heat Pumps and electric cars, is if everyone did this, would the national grid cope? I've no idea, plus there are questions on how all this additional electric would be generated?

 

So there you have it - still unfavourable cost wise and still questions environmentally. Everything just doesn't add up at the moment.

I don't disagree with most of your points, but I think the answer is "it depends".

 

We need to replace our boiler now, so hydrogen isn't an option. Also, the village I live in doesn't have mains gas, so I need an alternative to an oil tank on the drive. I know hydrogen can be stored safely, but I haven't seen any plans for a domestic product.

 

The gas distribution network could be repurposed, but it will need a lot of investment. Old steel pipes might be usable, but there is a risk of leaking even from steel pipes in good condition and all of the pumping infrastructure would need replacing. (The current stuff would mostly work with a natural gas/hydrogen mix, but that is only part of an answer.) It looks like there is a plan to replace most of the gas distribution network over the next 10 years - I really hope they invest in properly future proofing it (plastic pipes) by making it fully hydrogen ready, but that is more expensive. It also doesn't fix the issue for people whose boilers are broken now.

 

In terms of electrical grid load, I think it will need something clever doing to balance demand. The total capacity should be ok, but it probably can't deliver the peak load without some work. There are various options for this. Storage batteries either in homes or substations. Store energy as heat in hot water tanks to provide peak time heat from off peak electricity. Vehicle to grid so that when you get home from work, you plug your car in and it runs the heating during peak grid demand and then charges overnight.

 

We also need to remember that producing hydrogen requires a lot of energy, so we'll need more clean electricity generation anyway. The efficiency calculation on generating electricity to produce hydrogen which then needs to be distributed and then burned (or converted back to electricity in a fuel cell) versus distributing electricity to use in appliances directly becomes more complicated.

 

EVs can already work financially (for consumers, at least). Our lease cost for our main car is about the same as we were spending monthly on petrol and we were on the margin of replacing a 13 year old car anyway (expected repair bills in next 12 months greater than value of car). Our other car is newer and only does about 5k miles per year, so economically and environmentally it probably doesn't make sense to replace it now. I get that not everyone has a drive to charge at home and that needs to be solved, and replacing something that doesn't need replacing probably isn't beneficial environmentally, but as we're replacing our car and heating now and hydrogen isn't an option for either, I'd rather be investing in something that's currently much lower carbon and has the potential to be zero carbon.

 

It's going to be complicated and someone will have to pay, but we need to stop using energy that produces carbon dioxide. I hope we invest upfront, rather than waste money on lower carbon infrastructure and therefore need to replace it again to get to zero carbon.

[jmak]

Does anyone have some companies to look for? I've got a big garden to so hoping to do the ground sourced pump.

You'll want someone reasonably local - I was impressed with a couple companies in East Anglia, although nothing installed yet.

 

I thought I wanted ground source until I saw the cost [emoji44]. Ballpark was £40k!

[Michael]

I don't disagree with most of your points, but I think the answer is "it depends".

 

We need to replace our boiler now, so hydrogen isn't an option. Also, the village I live in doesn't have mains gas, so I need an alternative to an oil tank on the drive. I know hydrogen can be stored safely, but I haven't seen any plans for a domestic product.

 

 

I agree, if you don't have gas then your choices are limited.

 

It wouldn't be unreasonable to ask for your 'average user costs', for each type of fuel/method used to generate energy for a typical 3/4 bedroom house, then you have a direct comparative. I'd also encourage speaking to someone who's actually done it too. I did exactly this and it wasn't favourable in their case, but may not always be the case for all.

[Theblacksheep]

An Air Source Heat Pump will continuously turn a motor (which of course uses electric) to generate heat and heat your water cylinder.

 

So as it stands, your gas is roughly 2-3p per Kw and electric can be as much as 14p per Kw - all I can suggest is look at your current tariffs with your energy supplier.

 

ASHP is only 'on' when you are generating hot water, it is not continuously on, it only runs all day if you want it to. Under RHI you have an extra meter installed for the ASHP unit so you can see the watts draw is non-existent when not running.

 

1kwh of gas =/= 1 kwh of electricity =/= 1kwh of ashp output.

 

Gas boilers are 90% efficient, electric heaters are 100% efficient and ASHP are 100%-500% efficient. It depends on many factors, but at times it only takes 1KWH of electricity to generate 3kwh of hot water with an ASHP. I generate all my hot water at night on eco7, 5p a kwh at 200% efficiency it's cheaper to run than gas. Space heating during peak times is the big issue.

 

 

If the layout of the house would work easily I'd look into HVAC, going to need cooling more than heating in the future, and heating air with a reversible heat pump is much easier than heating water, then pumping it to radiators, and having that heat the air.

 

Not funded under RHI, so all the expense and none of the subsidies. Also, you still need hot water.

 

 

Does anyone have some companies to look for? I've got a big garden to so hoping to do the ground sourced pump.

 

Try Green Square depending on location.

Edited May 19, 2021 by Theblacksheep

[pooley]

I have one, installed as part of a pilot scheme a couple of years ago.

 

Massive Grey box in my garden - Mrs Poole hates it

Works out more expensive to run than just the gas boiler.

Still have a gas boiler that this Air pump uses if I ask for more heat than can be generated outside.

[Michael]

I have one, installed as part of a pilot scheme a couple of years ago.

 

Massive Grey box in my garden - Mrs Poole hates it

Works out more expensive to run than just the gas boiler.

Still have a gas boiler that this Air pump uses if I ask for more heat than can be generated outside.

 

Good feedback!

 

The grey box needs to be somewhere suitable, but ideally hidden as well I agree!

[mavhc]

All my appliances heat their own water, so I don't need hot water

[elsiegee40]

All my appliances heat their own water, so I don't need hot water

 

Including your taps?

[mavhc]

https://www.amazon.co.uk/Pudin-Electric-Instant-Stainless-Facilities/dp/B06XCS4MQT

[jmak]

https://www.amazon.co.uk/Pudin-Electric-Instant-Stainless-Facilities/dp/B06XCS4MQT

I don't think that would negate all my hot water needs, but it'd be a really useful addition and seems exceptional value.

 

Would be much more efficient than heating a whole tank (and waiting 20 minutes for that to happen before I can wash up). Not sure how it'll compare on price heating the perfect amount of water at peak price electricity vs excess water at off peak. Maybe I need a storage battery - or a Nissan Leaf!

[mavhc]

4-7pm is the peak time according to the national grid, they charge electricity companies for power moved over the grid during that period, so everyone get home, plug in your ev, cover the 4-7pm period, and then charge back up at midnight, that's the plan for 10 years.

 

Also have west facing solar.

[Rob_D]

Also have west facing solar.

According to the guys that put the system in here, PV panels are low cost enough that the larger surface area is better than making sure they're all facing south. (Only aspect they avoided was north-facing)

[the_quick]

We had something similar installed in a brand new flat - exhaust air pump made by Nibe. It was very cheap to run, but insulation was very good, even light switches had silicon around them to stop leaking air. As long as we run just using it without additional heat element switched on, it was very economical. We usually had it around 21C, so not cold really, never had problem with hot water. We love most that it kept flat quite dry and air was filtered quite well.

There were no parts outside, so possibly totally a different product.

[mikeprice]

Read something about this recently and the overall view was that ASHP (or Ground Source) was best considered as part of an overall plan including something to generate the power

e.g. Solar or Wind plus a battery

 

hence use the generating system to produce the power to power the pump - hence zero cost after installation.

 

I am thinking of getting (yet another) quote for solar to see how things have changed - if I do I will include some sort of heat pump and report back

 

Look like there is a small company near here that installs Solar and ASHP - I will see if I can contact them!

[mikeprice]

In addition

 

The recent government announcement that gas boiler will be discontinued is a real pain

 

When I moved in here (6 years ago) I updated the heating to a new efficient boiler and went from a hot water cylinder to a combi boiler

as suggested to be more efficient and hence eco friendly

 

now I will have to replace the boiler at just about the time that they can't be replaced any more!

and they now say I should have stuck with a hot water cylinder!

I understand the reasons but it is annoying

 

Which is why I want to start looking at possibilities now to move forward over time

 

It would help if teh government gave out incentives to convert over time - I have seen some mutterings (can you see a muttering???) but nothing concrete

[mavhc]

Problem is the time you want the heating most is when there's no sun for the solar panels, and the air is cold so the heat pump is least efficient.

[Andrew_C]

, and the air is cold so the heat pump is least efficient.

Less efficient. Define "so cold". There's still a lot of energy in the air at 273K.