Heat pump domestic heating

[Lucky Luke]

Hi, experts, recently, I heard about heat pumps for domestic heating and hot water. When I looked on the Web and saw one or two videos, I was overwhelmed by it all, being very aware that there are too many unknown factors in all this, for me to do anything about it.

Apart from the cost of having a heat pump installed, there is the fact that, with regard to storing any equipment, our small house (a semi) has only a small, under-stairs closet (access is via a door in the external wall). The CH boiler is installed there. It is quite small (there is room for the boiler, fixed to the wall, and for someone to stand in front of it, but there is very little space for stepping backwards, as the underside of the stairs would be in the way). Furthermore, the garden at the front of the house is very tiny (about 12ft X 8 ft, maximum), so I don’t know that this would be large enough to bury any pipes.

Is there anyone out there that is familiar enough, with this new heating, to point me in the best direction of making a preliminary enquiry about the pros and cons of installation, and the potential cost of it? I mean, there will be good and poor firms that do this work (in the UK).

Also, can that person tell me whether these outfits cost anything in the way of needing regular servicing?

I hope someone can give some useful information, as our boiler is now coming to the end of its life, and the idea of having a geothermal (or other) heat-pump seems to be the best way to go, if that is indeed possible.

Hoping for a helpful response,

L.L.

 

[endecotp]

It’s not “geothermal”.

Your garden is much too small for a ground source heat pump.

An air source heat pump would fit but I worry about the noise.

Is your house well insulated?

Your best plan is probably to replace your boiler when it fails with a new gas boiler.

 

[stem]

They are fine for new builds with top rated insulation, but not so good for retrofits. Firstly they can't generate the high temperatures associated with traditional boilers. So, in new premises heat pumps are usually used with underfloor heating which offers a much larger area as a heat emitter than a radiator, or as ducted blown warm air which provides the option of cooling (aircon) in the summer.

For existing properties the installation of underfloor or ducted heating systems will be cost prohibitive for most people, and if a heat pump were connected to existing radiators they will become only lukewarm. So, to achieve a comfortable temperature it would require, more, or larger radiators installing. Even then my experience is that most heat pump installations have to be run for 24 hours a day in very cold weather to maintain a comfortable indoor temperature.

Secondly, most systems will have an 'air source heat pump' [unless you have acres of land and a massive installation budget and can install a 'ground source heat pump'] With air source heat pumps, as the air outdoor temperature drops to single figures there is less heat available from it when you need it most. Also, because the outdoor unit gets much colder than the ambient air temperature, they can freeze up frequently and have to defrost themselves. My experience is that this defrosting can take up to as much as 20 minutes each hour, during which time no heat is made available to the property.

Finally because of the low temperature they produce, domestic hot water doesn't reach a useful or safe (to kill legionella) temperature, so either a top up, or separate hot water heating system is required.

Personally, I would definitely go for a heat pump if I had a super insulated home with underfloor heating and a ground source heat pump. I wouldn't entertain anything else at the moment.

 

[Lucky Luke]

They are fine for new builds with top rated insulation, but not so good for retrofits. Firstly they can't generate the high temperatures associated with traditional boilers. So, in new premises heat pumps are usually used with underfloor heating which offers a much larger area as a heat emitter than a radiator, or as ducted blown warm air which provides the option of cooling (aircon) in the summer.

For existing properties the installation of underfloor or ducted heating systems will be cost prohibitive for most people, and if a heat pump were connected to existing radiators they will become only lukewarm. So, to achieve a comfortable temperature it would require, more, or larger radiators installing. Even then my experience is that most heat pump installations have to be run for 24 hours a day in very cold weather to maintain a comfortable indoor temperature.

Secondly, most systems will have an 'air source heat pump' [unless you have acres of land and a massive installation budget and can install a 'ground source heat pump'] With air source heat pumps, as the air outdoor temperature drops to single figures there is less heat available from it when you need it most. Also, because the outdoor unit gets much colder than the ambient air temperature, they can freeze up frequently and have to defrost themselves. My experience is that this defrosting can take up to as much as 20 minutes each hour, during which time no heat is made available to the property.

Finally because of the low temperature they produce, domestic hot water doesn't reach a useful or safe (to kill legionella) temperature, so either a top up, or separate hot water heating system is required.

Personally, I would definitely go for a heat pump if I had a super insulated home with underfloor heating and a ground source heat pump. I wouldn't entertain anything else at the moment.

Stem, I thank you for that wealth of information and advice. It's just what I needed. In due course, we will buy a new gas boiler.
L.L.

 

[Lucky Luke]

It’s not “geothermal”.

Your garden is much too small for a ground source heat pump.

An air source heat pump would fit but I worry about the noise.

Is your house well insulated?

Your best plan is probably to replace your boiler when it fails with a new gas boiler.

Thanks for your response also, endecotp. I was not keen on the idea of an air-source pump, as it happens. What Stem has said clinched it! And our house is not really well insulated.
L.L.

 

[bernardgreen]

Personally, I would definitely go for a heat pump if I had a super insulated home with underfloor heating and a ground source heat pump. I wouldn't entertain anything else at the moment.

An acquaintance who was selling ASHP systems a couple of years ago ( " best clean green heating " ) has ceased the business having found the systems do not come up to expectations and invoke complaints from neighbours ( the noise ? )

 

[Lucky Luke]

An acquaintance who was selling ASHP systems a couple of years ago ( " best clean green heating " ) has ceased the business having found the systems do not come up to expectations and invoke complaints from neighbours ( the noise ? )

I'm thankful to have posed my enquiry on this forum. The stuff that I first saw, on the Web, blew me away!
L.L.

 

[Bodgedbuild]

The newest systems are lightyears ahead of those from only 3 or 4 years ago, I have a Hitachi Yakuti 80 series heat pump and the water is hot enough to scald if turned up, its downside is that it requires both indoors and outdoors units with the indoor unit being about the size of a washing machine. My mother-in-law has a regular temperature unit and she was advised to have larger rads fitted, she need not have bothered though (and I would not have got a "hot unit), her unit can easily heat the rads hot enough that you cannot leave your hand on them for long. The regular temperature units only require an outdoor unit that looks like an aircon unit and heat to around 65 degrees vs 45 degrees that they used to be 3 or more years ago.
It is expensive but eligible for government grants. If you have access to gas, I would use that, its still the cheapest but if you do not, I would recommend seeing if you can a demonstration.

 

[Harry Bloomfield]

Roughly, for every 2Kwh of heat you get out of them, you pay for 1Kwh of electric, so around 200% efficient. Fine if you have no alternative to electrical heating, but the colder it is outdoors the less efficient they become = at the time when you need more heat, there is less available.

Electric costs around 4x the cost of gas, so swap your gas boiler for one of these systems and your heating bill will double.

 

[Lucky Luke]

Roughly, for every 2Kwh of heat you get out of them, you pay for 1Kwh of electric, so around 200% efficient. Fine if you have no alternative to electrical heating, but the colder it is outdoors the less efficient they become = at the time when you need more heat, there is less available.

Electric costs around 4x the cost of gas, so swap your gas boiler for one of these systems and your heating bill will double.

Point taken, Harry. Thanks!
L.L.

 

[Lucky Luke]

It is expensive but eligible for government grants. If you have access to gas, I would use that, its still the cheapest but if you do not, I would recommend seeing if you can a demonstration.

Bodgedbuild, I'm afraid that, even if they are now as good as you say, the cost would be a huge factor. Also internal space.
L.L.

 

[StephenStephen]

I'm thinking that it'll be interesting to see how the maths changes with newer time of use electricity tariffs - electricity can cost 4 times as much as gas, but there are also (admittedly rare) times when you can get paid to use electricity, and certainly lots of times of day when electricity cost is comparable with gas.

 

[Harry Bloomfield]

I'm thinking that it'll be interesting to see how the maths changes with newer time of use electricity tariffs - electricity can cost 4 times as much as gas, but there are also (admittedly rare) times when you can get paid to use electricity, and certainly lots of times of day when electricity cost is comparable with gas.

Using it when cost was lowest or even (I heard) being paid to use it, would involve require massive heat storage to cover for the times when the cost was high.

 

[Bodgedbuild]

Bodgedbuild, I'm afraid that, even if they are now as good as you say, the cost would be a huge factor. Also internal space.
L.L.

I'd stand with the others on here if you have gas available to use that. If you do not though you can have a unit that takes no space apart from a hot water tank, it is only the 80 degrees Centigrade units that have an indoor part. You would need outdoors space for, effectively, an air conditioning unit.
I will be getting almost 2/3rds of my install cost back in Grants, I believe they have reduced that slightly now though to around half for new applicants