Does anyone have any knowledge about getting a heat pump replacement for a regular gas boiler please? We have a micro bore system currently, and have been told we need all pipe work replaced by 15mm. Is this correct, or are we being sold an expensive option? Thanks.
My solid fuel heating system was recently replaced with an air source heat pump system.
Heat pump systems work with a relatively low water temperature therefore a greater flow rate is required, necessitating larger bore pipework and larger capacity radiators.
Mine has been installed since the beginning of the year and up to now it appears appears to be very efficient.
Swapping to a heat pump from traditional boiler with small bore pipework will be a case of rip it out and start again.
Heat pump, larger diameter pipework and resized radiators (although this isn't ideal, underfloor pipework is far better).
You also need to ensure the house is very well insulated as heat pumps don't produce the heat of gas so flow temperatures are much lower. If heat is being lost faster than it can be produced due to poor insulation you will never be warm.
Quote: Originally posted by minicamper2001 on 22/7/2022
Does anyone have any knowledge about getting a heat pump replacement for a regular gas boiler please? We have a micro bore system currently, and have been told we need all pipe work replaced by 15mm. Is this correct, or are we being sold an expensive option? Thanks.
It’s correct for an “air to water” heat pump.
And yes, it’ll be expensive because the bigger pipes can’t go behind the skirtings like the microbore ones do. That system usually gets abandoned in situ, it’s not worth the hassle of taking it out. You’ll need a water tank too, so you may lose a cupboard.
I do know someone who installed an “air to air” heat pump (which acting in reverse is an air con unit) in a big kitchen extension.
Quote: Originally posted by minicamper2001 on 22/7/2022
Does anyone have any knowledge about getting a heat pump replacement for a regular gas boiler please? We have a micro bore system currently, and have been told we need all pipe work replaced by 15mm. Is this correct, or are we being sold an expensive option? Thanks.
Heat pumps need at least a 15 mm piping to work and in some circumstances 22 mm would be better. So the conversion will be very disruptive. There are also questions on how efficient air source pumps are as they often need to be backed up by electricity to supplement the heating. Ground source heating systems are apparently more efficient but of course much more expensive to install. Might I suggest you have a look at the Skill Builder Channel on YouTube which will explain the pros and cons.
Have looked into the efficiency of heat pumps, and had looked at any info that I can find. As yet I am still not convinced that heat pumps are a viable replacement for gas centrall heating. The heat output of them is very low compared to gas. The change over from gas seems to be incredibly expensive.With the disruption of a complete new system needing to be installed.
The long term maintenance of them being an unknown at the moment, As is the durability and life span of them. They also rely on elecricity to function with the hot water needing an electric boost , With the cost of electricty going up who knows where it will stop.
For those reasons we chose to go a slightly different route, and have had a high efficiency wood burner installed.
It does seem bizarre to use electricity generated by a gas fired power station to run an air source heat pump to heat water for radiators, rather than the more direct route of using the gas boiler in the house to heat the water.
The heat pump also gets less efficient as the outside air temperature gets colder, so there will be times when supplementary heating will be needed, such as multi fuel stoves or oil filled radiators.
Maybe night storage heaters will come back!
Some years ago a small development of new houses was built in Braemar (Scottish highlands). They had both air source heat pumps - and a conventional fire to supplement them. During the first winter, the temperature fell so low that the pumps wouldn't work and had to be replaced with uprated ones. This might not be the case further south, but the efficiency does drop off in colder weather.
If you have a large garden, a ground source pump might prove to be a better choice. In any case, I don't think it's a good choice for retro-fitting. A heat pump system best needs to be incorporated in a house specifically built to utilise it.
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Quote: Originally posted by Fiona W on 23/7/2022
It does seem bizarre to use electricity generated by a gas fired power station to run an air source heat pump to heat water for radiators, rather than the more direct route of using the gas boiler in the house to heat the water.
The heat pump also gets less efficient as the outside air temperature gets colder, so there will be times when supplementary heating will be needed, such as multi fuel stoves or oil filled radiators.
Maybe night storage heaters will come back!
The idea is that the heat pump extracts heat from outside and gives you 3 or 4 times as much heat as you would get from the electricity used. That is energy saving. Also, gas is a CO2 emitter and eventually they will source electric from renewables such as solar PV or wind.
We did try using gas fired heat pumps in a few schools and they worked well. However, as we had to do carbon emission calculations for building regulations it scored far worse than an electrically powered system scored. We stopped using them after that.
The trouble with air heat source pumps is that they are not very efficient in winter so has to be supplemented with electricity to maintain temperatures, As Fiona has pointed out. Ground heat source would be better but difficult to install unless you have the land around the house. There is also the problem with anyone who has a small house as all the kit and extra tanks and piping takes up a lot of extra room. I think it would be better for the Government to insist that all new house were designed to have air heat source pumps and leave the existing housing owners to decide which is the best option. For me that would be to retain my current gas Combi. Given that you will have to use electrics to supplement an air heat source I would have thought there would an advantage to also fit solar panels and a storage battery as a means of reducing your reliance on the grid?
We replaced our 20 year old, but still serviceable, gas boiler for a new condenser one last year. It should see us out and is definitely more efficient.
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We have recently upgraded, we looked at heat pumps but, with the disruption of replacing the microbore pipe, cost of running and installation we decided to opt for a hydrogen ready condensing boiler instead.
New build is the way to go. “Gas boilers will be banned from new-build homes in Scotland by 2024 despite concerns that the electricity grid does not have the capacity to deal with green alternatives.” (Says The Times.)
Not sure if that’ll mean air source heat pumps as there aren’t so many technicians able to fit them yet. Might just mean panel heaters & electric immersion heaters, hopefully with solar backup. I’d retrofit a clean air compliant multifuel stove & flue too.
At the moment, until there’s a lot more local battery storage (a battery “farm” has just been built at my nearest wind farm), wind turbines turn off when the wind is strong as the transmission system can’t cope with the surge.
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Topic: Central heating heat pump
via mobile 22/7/2022 at 3:11pm
