Heat Pumps and 10mm Microbore Piping

[EuroTrotters]

Hi

Has anyone had their gas/oil central heating upgraded to an Electric Heat Pump and had any issues?

Ive heard that the flow and the fact that new heat pump systems are pressurised can cause flow issues along with leaks.

 

[bigwood]

The people next door have recently had a heat source pump fitted. Like us there gas heating was mostly 10 mm pipe so they had to have the pipes changed to 15 mm and some radiators had to be changed. Whilst the work was being done there front garden looked like a scrap yard.
As an add on they have had solar panels fitted to help with the electric bills.

 

[Googlebot]

I am no expert, however from what I know heat pumps don’t heat the water up much. You therefore need a large radiator and surface area to get the heat transferred to the room effectively. For that reason you generally need bigger radiators than a normal system.

Microbore systems only have the capability to supply a limited amount of heat, therefore are subject to limitations in heat output per radiator. That said, there is less water in a microbore system so it will heat up quicker and take less energy to keep it at temperature.

I suspect in the real world, you will probably get away with the 10mm pipe.

 

[RetiredPope]

My daughter is having a heat pump fitted to replace her oil heating next month. During the survey they stated that you can't run a heat pump through microbore pipe work. This was dissappointing news for us as ours is all microbore. If we want to switch we need to have all radiators re-plumbed.
In daughters house they have recommended replacing 2 of her radiator for larger ones, the others being OK. she lives in a 3 bed semi circa mid 70's build.

 

[Ejaydee]

We have an ASHP, and I can confirm micro bore pipe is not good. You will need 15mm as a minimum (unless things have changed in the last couple of years). Unfortunately, many UK properties will have to have quite a lot of work done if they are to have a heat pump installed and for it to be efficient. Good insulation is a priority and increased sizes for radiators (I have Thermoskirt (aluminium skirting boards) fitted around the house and underfloor heating in the bathroom).

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[ctc]

And no doubt a sharp intake of breath before they worked out the cost of the extra plumbing.

 

[Plumb]

My daughter is having a heat pump fitted to replace her oil heating next month. During the survey they stated that you can't run a heat pump through microbore pipe work. This was dissappointing news for us as ours is all microbore. If we want to switch we need to have all radiators re-plumbed.
In daughters house they have recommended replacing 2 of her radiator for larger ones, the others being OK. she lives in a 3 bed semi circa mid 70's build.

Not quite sure of the relevance of pipework sizing ! After all the heat pump is only another form of heating energy medium no difference gas ,oil , coal electric all the same as far as system heat requirements

 

[Clipgate]

Heat pumps have a great deal of development to go in my view, a average flow temperature is around 65deg C the oil boiler on average 85degC.
In order to maintain a safe temperature in the supply most pumps fit an auxiliary electric heater to supplement the temperature.
The insulation and supply piped need to be designed carefully as does the radiators etc.
I researched the possibility myself carefully and visited customers who had the system fitted.
Yesterday one customer contacted me to say since fitting the cost has risen to around £10 per day this time of year, and this augmented by a wood burner, from oil costs of around £4.50 per day.
If you research on utube a number of professional installers have posted advice, which can if course be ignored however may be worth serious consideration.
This one with hands on experience.

 

[gpat]

Not quite sure of the relevance of pipework sizing ! After all the heat pump is only another form of heating energy medium no difference gas ,oil , coal electric all the same as far as system heat requirements

The pipework size is important as you generally have to get a greater flow of water through the system. Its a simple flow/pressure relationship

Therefore you have 3 choices

1) Increase the pressure to achieve the flow through the existing pipes
2) Increase the pipe bore to increase the flow without higher pressure or
3) Both

 

[Odd-no-more]

After all the heat pump is only another form of heating energy medium no difference gas ,oil , coal electric all the same as far as system heat requirements

Air source heat pumps have a much lower flow temperature than other forms of heat engine. In the 1970's systems were designed with a flow temperature of 80 deg heat pump will do about 60deg that's why larger radiators are needed

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[Plumb]

The pipework size is important as you generally have to get a greater flow of water through the system. Its a simple flow/pressure relationship

Therefore you have 3 choices

1) Increase the pressure to achieve the flow through the existing pipes
2) Increase the pipe bore to increase the flow without higher pressure or
3) Both

Still don’t know why increased pipe work necessary you are transferring less energy to the radiators ! Yes an increase in radiator surface area will possibly be needed it all relies on mean water temperature differential.

 

[Odd-no-more]

I would not have a have an air to water heatpump but I am getting an air to air heatpump, just one at the moment to see how well it does, I know they work well but can be noisy. If it works we will only use the heating in the morning and late evening and use the heatpump to keep the main room warm in the day and if it's good I will add more units to heat the whole bungalow. If it doesn't work I will at least have air-conditioning in the main room for the summer.

 

[Plumb]

Heat pumps have been around donkeys years and never very efficient and consequently never caught on

 

[Richard n Ann]

I'd consider a multi split system. No faffing about with water pipes, easy to fit and efficient

 

[acropolis22]

Heat pumps have been around donkeys years and never very efficient and consequently never caught on

But used widely in Scandinavia and Germany? I think if they are not installed in a suitable situation they will be inefficient.

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[Richard n Ann]

But used widely in Scandinavia and Germany? I think if they are not installed in a suitable situation they will be inefficient.

Also if the water temperature is set too high the compressor runs continuously which isn't good.

 

[Steve N Tracy]

There is a Scandanavian company that have developed a heat pump system that runs at a higher temperature so it is a straight swap for a gas boiler,
https://group.vattenfall.com/uk/new...hes-heat-pump-solution-to-replace-gas-boilers

 

[acropolis22]

Also if the water temperature is set too high the compressor runs continuously which isn't good.

Correct, although you don't want it cycling on and off either. Most efficient when it has a good run at it.....

 

[Odd-no-more]

There is a Scandanavian company that have developed a heat pump system that runs at a higher temperature so it is a straight swap for a gas boiler,
https://group.vattenfall.com/uk/new...hes-heat-pump-solution-to-replace-gas-boilers

I've had a quick look, they give no information on how they do it or the COP % or even the cost so I will wait and see. One thing is for sure, if their system works well, it won't be long before the big boys pinch it.

 

[Plumb]

Correct, although you don't want it cycling on and off either. Most efficient when it has a good run at it.....

That applies to condensing boilers most efficient when running at the dew point to extract the latent heat so needs to run at a lower temperature

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[Odd-no-more]

Correct, although you don't want it cycling on and off either. Most efficient when it has a good run at it.....

I think most systems modulate in the same way as a gas boiler so as not to cycle

 

[Plumb]

But used widely in Scandinavia and Germany? I think if they are not installed in a suitable situation they will be inefficient.

Not sure why they would be any more efficient in those countries the law of physic’s doesn’t change.

 

[acropolis22]

Not sure why they would be any more efficient in those countries the law of physic’s doesn’t change.

I suspect their housing stock is more recent than ours. So some of the basics are already in place. Well insulated property and underfloor heating to name but two?

 

[Odd-no-more]

Not sure why they would be any more efficient in those countries the law of physic’s doesn’t change.

They have much better insulation in their homes. The government likes to talk about saving energy, but the building regulations still don't insist on a heat recovery system for new builds, let alone triple glazing

 

[Plumb]

I suspect their housing stock is more recent than ours. So some of the basics are already in place. Well insulated property and underfloor heating to name but two?

Yes quite agree their insulation of properties are much greater than ours so use far less energy! If you switch the thing on it will use energy, they also probably have deeper pockets than us

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[BouncyBoatFolk]

I would not have a have an air to water heatpump but I am getting an air to air heatpump, just one at the moment to see how well it does, I know they work well but can be noisy. If it works we will only use the heating in the morning and late evening and use the heatpump to keep the main room warm in the day and if it's good I will add more units to heat the whole bungalow. If it doesn't work I will at least have air-conditioning in the main room for the summer.

We have warm air heating in our house [ Johnson Starley] . I did ponder an upgrade to an air source system, but the 25+ payback time frame put me off. Our current boiler is 28 years old and is serviced bi-annually as it only works for 5 months a year as the water is element heated by economy 7. Additionally, the air source is barely any more efficient and cost a fortune to buy initially, no brainer, keep the old system running as long as possible with a new thermo coupling every other year, and a new fan every other decade. Also we prefer the almost instant hit of warm air heating.
Mike.

 

[Odd-no-more]

We have warm air heating in our house [ Johnson Starley] . I did ponder an upgrade to an air source system, but the 25+ payback time frame put me off. Our current boiler is 28 years old and is serviced bi-annually as it only works for 5 months a year as the water is element heated by economy 7. Additionally, the air source is barely any more efficient and cost a fortune to buy initially, no brainer, keep the old system running as long as possible with a new thermo coupling every other year, and a new fan every other decade. Also we prefer the almost instant hit of warm air heating.
Mike.

If your unit fails you can get a unit to replace it that uses a standard gas boiler and a heatexchanger

 

[Plumb]

Johnson and Stanley are still in business in Northampton and have produced thousands of units over the years and would be able to supply a replacement unit compete I’m sure

 

[acropolis22]

We have warm air heating in our house [ Johnson Starley] . I did ponder an upgrade to an air source system, but the 25+ payback time frame put me off. Our current boiler is 28 years old and is serviced bi-annually as it only works for 5 months a year as the water is element heated by economy 7. Additionally, the air source is barely any more efficient and cost a fortune to buy initially, no brainer, keep the old system running as long as possible with a new thermo coupling every other year, and a new fan every other decade. Also we prefer the almost instant hit of warm air heating.
Mike.

Funny isn't it how we are all different? I absolutely hate warm air heating. I don't especially like the dryness it produces in the atmosphere, and I really don't like the way it seems to go freezing cold a soon as it shuts off. Hey ho, each to his own.

 

[Plumb]

Funny isn't it how we are all different? I absolutely hate warm air heating. I don't especially like the dryness it produces in the atmosphere, and I really don't like the way it seems to go freezing cold a soon as it shuts off. Hey ho, each to his own.

I think when people already have a system the cost implications are a governing factor , also the instant heat factor can be beneficial,also some people prefer just having the registers rather than the radiators taking up wall space

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