Heat pumps

[thursday]

Hi

I am looking at possibly changing our mains gas boiler and interested in getting a heat pump (either air or ground) I wondered whether anyone on the forum had already installed a heat pump at their house and might be able to share some do's and don'ts? Is it hard to do? Was there a lot of insulation steps you had to go thorough? Does it provide a reliable source of heat and hot water?

Thanks

Thursday

[thursday]

thanks Cidolphus. I was really interested in getting some of the other view. Thank you.

[jc2]

I know someone who has one - keeps breaking down. Expensive and he said there are only about 3 people in the country who know how to fix them. The tech will get better though.

[kissthisguy]

Thanks for starting this thread. Wonder how appropriate they from a noise perspective for Victorian terraces? Are our back gardens all going to be humming in a few years?

[Guest]

cidolphus Wrote:

-------------------------------------------------------

> No, they are not a reliable source of heat and hot

> water. They are inefficient and their efficiency

> drops off significantly as the outside temperature

> falls whether is air source or ground source. This

> loss of inefficiency occurs when you need the most

> heat ie when the ambient temperature is low.

>

> Heat pumps are simply refrigerators working in

> reverse. So on a hot day your fridge motor runs

> much more consuming more energy. In cold weather

> your heat pump runs much more and consumes more

> electricity. They use a compressor, an evaporator,

> a heat exchanger and a fan. Lots of plumbing and

> connections. A gas boiler is much simpler, more

> efficient and much, much cheaper to install.

>

> I would never consider installing a heat pump, no

> matter how much spin the Govt puts on them. They

> make no sense whatsoever.

Saying that they make no sense whatsoever is completely false.

The technology is relatively simple, although retro-fitting them to an existing property is not straightforward.

If anyone has any specific questions about air or ground source heat pumps then please feel free to message me directly - I'm a Chartered Building Services Engineer with a degree in Mechanical Engineering and over 15 years experience of working with this technology.

[Dogkennelhillbilly]

cidolphus Wrote:

-------------------------------------------------------

> So on a hot day your fridge motor runs

> much more consuming more energy. In cold weather

> your heat pump runs much more and consumes more

> electricity.

Well, yeah - obviously any heat/chill source is going to consume more energy the greater the difference between ambient temp and target temp.

[Siduhe]

No specific experience but as I understand it, a key issue is how well insulated and draft proof your house is (as then the overall lower heat output matters less). How airtight is your home currently?

[Guest]

Siduhe Wrote:

-------------------------------------------------------

> No specific experience but as I understand it, a

> key issue is how well insulated and draft proof

> your house is (as then the overall lower heat

> output matters less). How airtight is your home

> currently?

This is a much cheaper and easier way to reduce your energy bills, especially in Victorian properties.

[kissthisguy]

very true @clintmcjam. A friend had secondary glazing put in last year and barely needs to heat the upstairs now. It's not the most attractive solution, but it's made a big difference.

This is a much cheaper and easier way to reduce your energy bills, especially in Victorian properties.

[Penguin68]

This is a much cheaper and easier way to reduce your energy bills, especially in Victorian properties.

Most Victorian (and Edwardian) properties are single skin (no cavity for cavity wall insulation)- so not that easy to insulate walls, and too much 'draft proofing' may well lead to undue levels of condensation. Draft proofing and then inserting air bricks to reduce condensation is a very round-about way of getting things done. Much of the local housing stock is not (in terms of its build) optimised around achieving zero carbon.

[boogalou]

Hi Thursday,

Fantastic news that you're considering doing this. Currently, there will be a relatively high upfront cost, but you may get some support from the government / council for that and you'll still hopefully make savings over the longer term - as illustrated by someone on twitter who's installed one already:

There're some great resources out there - Waltham Forest Council recently did a 'super-eco' retrofit a semi-detached Victorian home, which apparently you can actually visit until the spring.

https://astongroupuk.com/projects/retrofitting-a-victorian-property-in-london/

Do keep us updated with your progress.

[George Orwell]

It seems the Waltham Forest retro-fit is seen as successful.

The cost: ?115,245

[Mark]

George Orwell Wrote:

-------------------------------------------------------

> It seems the Waltham Forest retro-fit is seen as

> successful.

>

> The cost: ?115,245

That's the cost of the whole house refit (including garden landscaping), ?59k of the cost was paid for by a grant.

Heat pump and radiators system was ?10,200 and "the resident would save around ?860 per year and a carbon emission reduction of about 4240kg per year."

[heartblock]

Noisy and big... but I imagine future versions will be more reliable and quieter. It is a step forward but I think needs further development.

[gabys1st]

We also insulated our attic roof under the tiles as well as between the joists.. cost a bit but installers were in and out in a day. House is now warmer in winter and cooler in summer

[KidKruger]

I think also just wearing thermals and jumpers during colder periods helps reduce heating costs.

Some households seem to want to be able to walk around in shorts and vests as if it was summer, during winter, which is unrealistic.

Nowt wrong with feeling the actual season !

[George Orwell]

"Heat pump and radiators system was ?10,200 and "the resident would save around ?860 per year and a carbon emission reduction of about 4240kg per year."

Plus several thousand pounds for insulation.

Plus a few thousand pounds for redecoration.

Maybe ?25k - ?30k in total.

[Mark]

A breakdown of some items can be seen here https://astongroupuk.com/wp-content/uploads/2021/10/Greenleaf-Road-Retrofit-Factsheet-WEB.pdf:

Heat Pump and radiator system ?10,200

Solar PV and battery storage ?12,294

Underfloor insulation ?1,850

Solid wall insulation ?12,081

Loft insulation ?829

You need to add vat to those figures

Not sure what the breakdown of the grant was, but it was about ?59k

[Boddle]

We did some research on this and concluded that currently our Edwardian terrace just isn't able to accommodate it. We ended up with a hydrogen ready boiler instead, and hope that the technology will make it simpler soon

[Boddle]

We did some research on this and concluded that currently our Edwardian terrace just isn't able to accommodate it. We ended up with a hydrogen ready boiler instead, and hope that the technology will make it simpler soon

[redpost]

My friend has had an air source heat pump in his flat for 20 years now and it has never gone wrong, he has no gas so it works out quite a lot cheaper than electric heating. It struggles on the few very cold nights we get in London, but most of the time copes well. If you space for a ground source heat pump, then this should be even better.

I did a lot of work myself on our victorian house, we installed triple glazed windows, a heat recovery system (recycles heat from air) and insulated as best we could (thin 20mm PIR insulation on internal walls to avoid losing space, heavy insulation between floors and in loft where space was not an issue). Our house is very pleasantly warm with minimal heating, very well ventilated and the upper floors are still warm in the late afternoon when the heating has been off since 8am.

[Monkey]

Very useful thread. A silly question perhaps: are air pumps noisy? Worried about causing grief with neighbours.

[first mate]

I agree, the noise aspect could make them unsuitable for many urban dwellings, especially terrace homes where everyone is so close together.

[Cozza01]

Yes. We have an air source heat pump and have had one for the last 4 years. It has never gone wrong and if you wish to see one in action please PM me and I can arrange.

The comment that they inefficient and their efficiency drops off significantly as the outside temperature falls whether is air source or ground source. Is not incorrect but incredibly misleading!

From a physics case this is correct but the drop off is marginal and does not impact the warmth of the house because air source heat pumps work best in insulated houses. (Heat pumps are used in the Nordic countries which are significantly colder than the UK.)

My advice would be...until you have completed the following list of energy improvements....its not going to work that well in a victorian/edwardian house which just leaks heat. (No cavity wall insulation.)

1. Decent double glazed sash windows

2. Wall insulation - either inside or on the outside of the house...depending on if your house is brick or render. Insulation only needs to be on the external walls.

3. Under floor insulation plus and perhaps under floor heating - most houses are floorboards over dirt foundations not exactly robust from a heating perspective. (We have underfloor heating on the ground floor and radiators on the first and second floors.)

As to are they noisy, not particularly. There are planning rules on where they can be situated in relation to neighbouring properties but the installer will be able to confirm all of that.

Most people wonder about the difference in bills. Our house is around 3000 square feet and semi-detached and our energy bills are under ?80 a month. (For complete disclosure we do have solar panels too.)

[redpost]

Cozza01 Wrote:

-------------------------------------------------------

> Yes. We have an air source heat pump and have had

> one for the last 4 years. It has never gone wrong

> and if you wish to see one in action please PM me

> and I can arrange.

>

> The comment that they inefficient and their

> efficiency drops off significantly as the outside

> temperature falls whether is air source or ground

> source. Is not incorrect but incredibly

> misleading!

>

> From a physics case this is correct but the drop

> off is marginal and does not impact the warmth of

> the house because air source heat pumps work best

> in insulated houses. (Heat pumps are used in the

> Nordic countries which are significantly colder

> than the UK.)

>

> My advice would be...until you have completed the

> following list of energy improvements....its not

> going to work that well in a victorian/edwardian

> house which just leaks heat. (No cavity wall

> insulation.)

>

> 1. Decent double glazed sash windows

> 2. Wall insulation - either inside or on the

> outside of the house...depending on if your house

> is brick or render. Insulation only needs to be

> on the external walls.

> 3. Under floor insulation plus and perhaps under

> floor heating - most houses are floorboards over

> dirt foundations not exactly robust from a heating

> perspective. (We have underfloor heating on the

> ground floor and radiators on the first and second

> floors.)

>

> As to are they noisy, not particularly. There are

> planning rules on where they can be situated in

> relation to neighbouring properties but the

> installer will be able to confirm all of that.

>

> Most people wonder about the difference in bills.

> Our house is around 3000 square feet and

> semi-detached and our energy bills are under ?80 a

> month. (For complete disclosure we do have solar

> panels too.)

Well said, ground source will have very minimal drop off as temperatures drop, because pipes are buried and ground is near constant temperature all year round.

Air source efficiency does drop off as air temp drops as pump has to work harder, also the external coils get iced up and it has to go through a defrost cycle. However, this is minimal in london and most times of the year it will be working with an efficiency of around 3 COP ... which means 1kw of electricity gives 3kw of heat.

But, they are no magic bullet, your house needs to be well insulated as well .. and not just the low hanging fruit like draft excluders and loft insulation.