Heat Pumps & Hydrogen Powered Boilers Book

[joe90]

9 minutes ago, Marvin said:

The nearest mains gas here is MILES away

and me ?‍♂️

[ProDave]

Like others here, mains gas was simply not an option here, it is at least 3 miles to the nearest gas main.

 

But even if mains gas were available, there is the standing charge to consider.  A quick search suggests that is typically £90 per year.

 

So if I had installed mains gas just to heat my home, then the gas usage bill would have to be less than £160 per year for gas to be "cheaper" than my heat pump.

 

[IanR]

1 hour ago, billt said:

There are 22 million gas CH systems in the UK, 67,000 heat pumps is niche.

 

It would be more helpful if you compared apples to apples, rather than oranges.

 

22 million is the total number of properties that have a gas boiler, where as the 67,000 figure I quoted is the heat pump installs for 2020.

67,000 installs can not be considered as "niche", no matter what dictionary you are using for your definition.

 

1 hour ago, billt said:

A SCOP of 4.2 sounds rather optimistically high - it's only likely to be achievable with very low flow temperatures; IOW not when applied to a retrofit. A quick search finds a list of SCOPs for Vaillant ASHPs which range from 4.58 at 35C to 2.9 at 50C.

 

Nibe F2040-12 Quoted SCOP is 4.2. It actually performs better in my own property, but to save the detail I quoted the standard SCOP.

 

I pay 12.5p per kWh for my electricity, so by the standard SCOP I am paying 3p for every kWh of heat the ASHP produces.

A 90% efficient Gas Boiler requires Gas at 2.7p per kWh to be competitive. I'm sure somewhere in the country there is a deal that achieves that price, but it was never available to me at my last property where the cheapest I ever got it was 3.67p per kWh. And that excludes the additional standing charge for gas that @ProDave points out.

Edited August 13, 2021 by IanR

[Gone West]

On 09/08/2021 at 21:49, Des Ingham said:

What I would really love is some feedback from people who have heat pumps installed, I would like to know their thoughts, both positive and negative, about their heat pump.

Well Des, are you happy now you've kicked the top off the ants nest . I bet you weren't expecting this sort of response.

[Gone West]

For my part I was in the niche camp for the last few years but am now living in a converted old stone cottage. I designed and built my own house to PH standards and heated it with electric towel rails and an EASHP through the MVHR system. It was extremely comfortable and a cheap form of space heating and DHW heating. I now live in an old bungalow with solid stone walls which is heated with an oil fired rayburn and standard wet radiator system. I wouldn't dream of trying to heat this house with an ASHP as I am fully aware of the pros and cons of such a system.

[jfb]

Accepting the danger of appearing like a Dave apologist I feel like some responses to his original post are attacking the messenger rather than dealing with some of the issues.

 

the idea that we can just switch over from gas boilers to ASHPs en masse is deeply problematic. It is the sort of idea that could become government policy without really dealing with some of the issues. Draughty and poorly insulated old housing stock is not an ideal fit for heat pumps. Nor are new builds that scrape through building regs at best and at worst wouldn’t pass if we had a building regulation system fit for purpose.

 

Solutions to these problems are not straightforward but surely they have to include better building standards/regulation and decent incentives for upgrading housing fabric. Clearly we need to make the switch to heat pumps and reduce reliance on fossil fuels but this can only happen if government can think longer term and actually grapple with the issues. The message of reducing energy use rather than just switching to a ‘clean’ energy source needs to be hammered home and built into standards/incentives. Fabric first.

[Ferdinand]

9 minutes ago, jfb said:

Accepting the danger of appearing like a Dave apologist I feel like some responses to his original post are attacking the messenger rather than dealing with some of the issues.

 

the idea that we can just switch over from gas boilers to ASHPs en masse is deeply problematic. It is the sort of idea that could become government policy without really dealing with some of the issues. Draughty and poorly insulated old housing stock is not an ideal fit for heat pumps. Nor are new builds that scrape through building regs at best and at worst wouldn’t pass if we had a building regulation system fit for purpose.

 

Solutions to these problems are not straightforward but surely they have to include better building standards/regulation and decent incentives for upgrading housing fabric. Clearly we need to make the switch to heat pumps and reduce reliance on fossil fuels but this can only happen if government can think longer term and actually grapple with the issues. The message of reducing energy use rather than just switching to a ‘clean’ energy source needs to be hammered home and built into standards/incentives. Fabric first.

 

I think Govt policy has for a number of years required fabric improvements before renewable  technology gets funded.

 

A current example is I think the investment sequence imposed for GHG funding. Previously this also applied to funding for solar panels iirc under the FIT programme.

 

IMO there are three important lessons we have learnt:

 

1 - Gordon Brown's Code for Sustainable Homes taught us about the problems with gimmicks. 

2 - The Conservative programme thinking about funding out of energy bill savings taught us to keep it as simple as possible.

3 - The spiralling cost of FIT when it the arates were kept high enough to be free money taught us (I hope) about realism and keeping subsidies relatively small to maximise overall returns in CO2 savings.

F 

[SteamyTea]

22 minutes ago, Gone West said:

I wouldn't dream of trying to heat this house with an ASHP as I am fully aware of the pros and cons of such a system.

Apart from capital cost, why do you think it is unsuitable?

 

14 minutes ago, jfb said:

Draughty and poorly insulated old housing stock is not an ideal fit for heat pumps.

Same question?

[jfb]

19 minutes ago, SteamyTea said:

 

34 minutes ago, jfb said:

Draughty and poorly insulated old housing stock is not an ideal fit for heat pumps.

Same question?

Off top of my head.

- higher temperatures needed reducing efficiency 

- if replacing radiators for oversized to reduce temp needed then a significant cost and possibly unpopular if it means losing more usable space

- Ufh costs a lot to retrofit and needs insulation to be effective so larger cost

- issues with electrical supply on larger properties, possibly smaller ones too (to be fair I don’t know how easy to overcome this is)

- capital costs of replacing boiler for ashp

- waste of embedded energy of gas boiler if replaced before its’ usable life span

- finding space to fit new hot water tank if replacing combi boiler

[IanR]

The benefit of @SteamyTea asking "Apart from capital cost", is that it separates out the issues that get resolved with either carrot (grants) or stick (legislation) incentives from the Government, from the real practical issues.

 

44 minutes ago, jfb said:

- higher temperatures needed reducing efficiency 

- if replacing radiators for oversized to reduce temp needed then a significant cost and possibly unpopular if it means losing more usable space

- Ufh costs a lot to retrofit and needs insulation to be effective so larger cost
- capital costs of replacing boiler for ashp

 

Even in a "high energy loss" home, if you install large enough heat emitters you'll get the flow temperature down so that an ASHP can heat it with reasonable efficiency, you just need a large capacity ASHP. While theoretically possible, in the majority of cases it seems the wrong thing to do when an investment into the fabric of the building would reduce the energy losses, reducing the required emitter size and the ASHP size, so in turn reduce the day-to-day running costs.

There appears to be a yet-to-be-announced/legislated plan from the Government that will push to improve the fabric of existing buildings before any ban on the sale of fossil fuel boilers comes in to place.

Resolving the issues you mention above will require investment from the home owner, and where the home owner is not able to afford those changes: grants will be required either directly from the Government, or via the energy suppliers and in some cases will be paid for in part by the energy savings that come from those changes.

 

44 minutes ago, jfb said:

- issues with electrical supply on larger properties, possibly smaller ones too (to be fair I don’t know how easy to overcome this is)

- waste of embedded energy of gas boiler if replaced before its’ usable life span

- finding space to fit new hot water tank if replacing combi boiler

 

There are practical issues that some properties will have that will make a standard ASHP, UVC, large heat emitter installation difficult to achieve. ASHPs will not be the solution for all.

Larger properties that may require a move to a 3 phase supply from single phase, in some cases could make the change to electric heating impractical, however the more widespread requirement for upgrading the transformers to cover the higher capacity required as houses switch to electric heating you'd hope is covered within the infrastructure planning.

If the ban on the sale of fossil fuel boilers comes in soon enough, say 2030, then the majority of ff boilers will have reached their end of life before 2050, so few would be forced to change before their reasonable lifespan is up.   

[ProDave]

This is getting off topic, but the issues I see with older houses are as above.  We used to live in a 1930's semi that leaked heat like it was going out of fashion.  We built an extension in the 1990's that was a bit better but not a lot.  That was heated with an LPG boiler with an eye watering appetite for gas.  But I didn't know any better.  I grew up in a similar 1930's semi that sometimes in winter could not even maintain a comfortable temperature in spite of the radiators being piping hot, and just accepted bedrooms were cold places especially at night when the heating went off and they quickly cooled down.  I suspect there are still a LOT of people accepting this level of heating as "normal" and think nothing of it.

 

Yes in theory you could heat that house with an ASHP, but it would have to deliver as much heat into the house as the gas boiler did, and would as a minimum need larger radiators to operate at a lower temperature.  As has been mentioned it would never match gas prices, a well designed system might get close but would never match it.  So you would need much larger radiators, a very large heat pump, possibly an upgrade to a 3 phase supply to power it? and the "benefit" for all your efforts and capital outlay would still be higher bills.  So I would certainly not be advising an ASHP for that type of house.

 

The elephant in the room, and a problem that must be solved is just what are we going to do to all the houses like this to make them more energy efficient, and who is going to pay for it?  What is really needed is a strip back to bare shell, insulate everything and seal it for decent air tightness and then while doing that level of refurb fit UFH and then it might be a candidate for a sensible size heat pump.

 

There was a bit on the STV news recently about them doing exactly that to a Glasgow tenement block as a test bed to see exactly what is required to bring the building up to a modern standard.  The brief shots they showed appeared to show wood fibre or similar insulation slabs being used to line all the external walls on the inside.

[Declan52]

The Republic of Ireland had the right idea. They brought forward much stricter building regs and introduced a new standard where all new homes being built from 2020 had to be low energy homes. In order to have gas installed you had to overcome that many hurdles that a heat pump was the preferred option. Oil boilers in New builds will be banned from 2022 and gas 2025. So they are already miles further down the path than the UK are. A standard new build house built by a large developer in the UK isnt going to be suitable for a heat pump as they will have just scraped past the poor building regs we have. In Eire they are suitable. Changing the regs is the only real solution along with actually testing each house performance not just 1 in every 20.

To get round the issue of older housing stock if you are doing a renovation then in order to meet the much higher building regs the government will give you a grant to install towards EWI and better Windows and what ever else you want to do. 

[Gone West]

2 hours ago, SteamyTea said:

Apart from capital cost, why do you think it is unsuitable?

In our case it's the capital cost and disruption, along with not wanting very thick radiators or walls covered in radiators. With this sort of building the best solution would be to build an energy efficient replacement house. I have already done that and don't have the funds to do it again. We are lucky that the house came with a 4kW PV system and solar thermal which has provided most of our hot water. The FiT payments, when we get them, should cover our oil costs. Not very 'green' but as I say I've already been there and done that.

[SteamyTea]

56 minutes ago, Gone West said:

In our case it's the capital cost and disruption, along with not wanting very thick radiators or walls covered in radiators. With this sort of building the best solution would be to build an energy efficient replacement house. I have already done that and don't have the funds to do it again. We are lucky that the house came with a 4kW PV system and solar thermal which has provided most of our hot water. The FiT payments, when we get them, should cover our oil costs. Not very 'green' but as I say I've already been there and done that.

Now you are in a much milder climate (was it Kent before), you may find yours heating demand is lower.

[SimonD]

10 hours ago, IanR said:

It would be more helpful if you compared apples to apples, rather than oranges.

 

22 million is the total number of properties that have a gas boiler, where as the 67,000 figure I quoted is the heat pump installs for 2020.

67,000 installs can not be considered as "niche", no matter what dictionary you are using for your definition.

 

In 2019 there were approximately 1 heat pumps installed for every 120 gas boilers installed new. This was about 1.2 million gas boilers, a number that is increasing every year. 2020 may have been 1.5 million gas boilers. Heat pump installations have grown in number, but the latest figures I saw reckoned heat pumps made up maybe 1% of total new heating installations.

 

This is a sorry situation indeed given how mature the heat pump market is and it's a testament to how useless UK government policy is on affecting a necessary change.

 

There is also the problem that just as with gas, there don't seem to be enough installers qualified to do the number of installs of heat pumps necessary.

 

13 hours ago, IanR said:

A 90% efficient Gas Boiler requires Gas at 2.7p per kWh to be competitive. I'm sure somewhere in the country there is a deal that achieves that price, but it was never available to me at my last property where the cheapest I ever got it was 3.67p per kWh. 

 

It depends entirely on your location. Round us, we can't get a green electricity tariff below about 18.5p. Ours, which I know is properly green (i.e. zero traded certificates) is just over 20p. We have a 'green' gas tariff of 4.26p. Last year when I did my full calculation I needed a COP in excess of 5 to make financial sense in terms of running costs.

 

For me the argument for/against heat pumps just needs to be a bit more nuanced as it's all about balance, compromise and context.

 

For example, the overall environmental impact, calculated to consider wider impacts than just CO2 is worse for heat pumps than for gas boilers. If you only take into consideration CO2 it's a different kettle of fish.

 

Interestingly there's been a recent paper looking at methane emissions, essentially saying that the primary short term goal re global warming should be to minimise methane emissions, especially from disused oil and gas fields, farming, waste, and other industries and that it would make sense to burn this. This is obviously contentious right now.

 

Heat pumps do work and they're an amazing technology, but they do have some fundamental drawbacks (compared to a narrow view of current heating demands) that need to be understood, recognised and compensated for accordingly. Likewise gas boilers could be far more environmentally friendly than they are currently (e.g. using green gas).

 

The elephant in the room as always is that if you want to cut emissions, it's actually far 'easier' to do it by reducing consumption than by trying the generate the necessary energy by alternate means, which means as most have already said, upgrading housing stock. But unfortunately, as can be seen in the recent proposed policies by this government, they want to avoid this, searching (hoping?) instead for silver bullet technology. They also have in place many policies that prevent, and/or increase the cost of retrofit upgrades, and the full utilisation of renewable energy.

 

For me, heat pumps are only a part of the total solution to the problems we face.

[SimonD]

1 hour ago, ProDave said:

The elephant in the room, and a problem that must be solved is just what are we going to do to all the houses like this to make them more energy efficient, and who is going to pay for it?  What is really needed is a strip back to bare shell, insulate everything and seal it for decent air tightness and then while doing that level of refurb fit UFH and then it might be a candidate for a sensible size heat pump.

 

Sorry, have to laugh as I've been catching up with this thread and almost said exactly the same thing starting with 'the elephant in the room' ?

 

But I do agree, it's fundamentally about 1st reducing energy consumption, making homes more energy efficient, and then looking at the appropriate solution for heating and DHW.

 

A while back I read a research paper comparing carbon emissions for passivhaus retrofit upgrade and demolition/new build passivhaus and the conclusion was retrofit favourable (obviously depending on overall context).

 

[Gone West]

18 minutes ago, SteamyTea said:

Now you are in a much milder climate (was it Kent before), you may find yours heating demand is lower.

We shall see, I've certainly noticed that the climate is very different from East Kent, much more agreeable for us.

[willbish]

1 hour ago, SimonD said:

 

For example, the overall environmental impact, calculated to consider wider impacts than just CO2 is worse for heat pumps than for gas boilers.

Can you explain this? Is it because of the refrigerants used?

Edited August 14, 2021 by willbish

[SteamyTea]

1 hour ago, willbish said:

Can you explain this? Is it because of the refrigerants used?

I have not bothered to look into this much, but there is a CO₂ equivalent with refrigerants. But not all of them will leak.

Natural gas, by its very chemistry, will produce CO₂ when burnt in air. Electricity can be very clean.

There is also an infrastructure issue, we have one network that is multi use i.e heating, cooking, lighting, machinery and transport, and another that is just heating and cooling. There will be a carbon cost to that.

Edited August 14, 2021 by SteamyTea

[SimonD]

2 hours ago, willbish said:

Can you explain this? Is it because of the refrigerants used?

 

It's partly to do the the use of refrigerants as this does have high ozone depletion potential as the refrigerants do leak during both manufacture and use and need to be safely disposed of at the end of their life. However the development of CO2 as a refrigerant is a good thing here. Overall it's more in terms of the whole life cycle impact being more complex for heat pumps than gas boilers, which rightly includes the environmental impact of UFH systems, for example. Total figures come from the raw materials, energy and wastage associated with the life of the pump including for instance:

 

1. Extraction and processing of raw materials

2. manufacturing of pump components and assembly

3. installation

4. operation

5. UFH system manufacturing and contruction

6. Fuel extraction and processing for electricity generation

7. generation of electricity

8. transmission and distribution of energy

9. decommissioning - recycling and disposal of heat pump and related installations

 

The electricity generation side has changed significantly in the last 10 years which has resulted in most of the CO2 benefits of heat pumps coming into play in the UK. In other countries that have relied on a better input of renewable energy (e.g. Sweden) the figures are a bit different. But even so, the true nature of the global warming benefits of heat pumps is still more complicated than often assumed (e.g. electricity is more efficient so therefore it's the best option type assumption) - John Cantor has a good blog post about this - Heat Pump global warming effects

 

The figures for these are changing all the time so I wouldn't be surprised to see different conclusions on environmental impacts over the next 10 years. It's all shifting ground.

[willbish]

Any piece of tech or equipment has lifetime impacts to consider, I don't see anything to suggest that a heat pump has substantially greater lifetime impacts which counter their major benefit of running on (ever greener) electricity?

 

I'm not sure low temp UFH has higher total impacts either. Conventional steel rads inevitably rust and go out of fashion requiring replacement. UFH pipes have the potential to work for a generation at least. Also many gas boilers use UFH as emitters.

 

Still confused by this statement

 

5 hours ago, SimonD said:

the overall environmental impact, calculated to consider wider impacts than just CO2 is worse for heat pumps than for gas boilers.

 

[joe90]

The trouble is we are all getting (got) soft, when these draughty leaky houses were built they were considered better than what existed before (caves?) . Everyone now expects to walk around their  house wearing little in the way of clothes and in temps of 21’ or above. Central heating is treated as a norm. I grew up in a house with one open coal fire, heavy bed linen and a jumper when it was cold and frankly I believe more healthy. 
 

ah, but we had it tough, had to lick road clean etc etc ????

[ProDave]

These old leaky houses "worked" as long as you throw a lot of heat into them.  Fine when it is cheap and the consequences (MMGW) don't matter.  But now we know with a properly built house you CAN walk around all year in your tee shirt without needing a lot of energy input to keep it that way.  The "solution" is known.  It's how we get from the old housing stock we have to that, that is not yet known.

[Gone West]

13 hours ago, joe90 said:

I grew up in a house with one open coal fire, heavy bed linen and a jumper when it was cold and frankly I believe more healthy. 

I would be very surprised if using an open coal fire was considered healthy.

[joe90]

2 minutes ago, Gone West said:

I would be very surprised if using an open coal fire was considered healthy.

Ha, I meant not overheated ?