Heatpump

pep.fermi

I'd like to hear stories on central heating with a heatpump, rather than gas.

Our house was built 2019. At the time the housebuilder offered us to chose between gas and heatpump, the latter would have costed 30k more. Running cost would have been similar: heatpump needs 1/3 the energy (varies a lot, depending on the type, more efficient ones have lower running costs but cost much more to buy and install), but energy is electricity that costs x3 gas. Not sure maintenance costs, reliability etc. We opted for gas, because the lower cost. But I'm a hard core enviromental fanatic and I now regret the choice. So I'm contemplating replacing gas-boiler with heatpump, though doing it now is of course silly, should have done it then.

I'm still shocked by the fact the heatpump are so bloody expensive.
Informal recent quotation was ca 40k.

Anyone here changed from gas to heatpump?
Cheers,

Pross

No experience of them but is that price for air source or ground source? It's about two or three times what I believe an air source heat pump would cost in the UK.

I know there are a few on here that have heat pumps and previous comments seem to give mixed reviews.

davidof

pep.fermi said:

I'm still shocked by the fact the heatpump are so bloody expensive.
Informal recent quotation was ca 40k.

Two houses next door have heat pumps. Both ground sourced. I was surprised at the maintenance charges for what is essentially a fridge in reverse. 250 quid per year. That is my hot water heated for the year for 3.

40K is crazy for a bit of pipe and an electric motor though, that's a lotta gas.

ugo.santalucia

Sensible advice would be to wait until your boiler needs replacing, which might be another 6-7 years. In the meantime, hopefully the price of heat pumps will go down. I am assuming your house is fairly well insulated (cavities, loft, triple glazing etc..).

Price of gas and electricity will still be linked for quite a long time.

joeyhalloran

Edited: decided post was off topic

ugo.santalucia

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

Pross

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

You probably won’t have a choice next time your boiler needs replacing as gas versions will be banned but yes, hopefully they’ll be significantly cheaper by then.

ugo.santalucia

Pross said:

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

You probably won’t have a choice next time your boiler needs replacing as gas versions will be banned but yes, hopefully they’ll be significantly cheaper by then.

I've got the feeling all these dates will be postponed in the end...
How much more electricity will be needed if every household went fully electric? So, heating, cars etc... how many new power stations (or equivalent renewables) will be needed per year to get there?

pblakeney

ugo.santalucia said:

Pross said:

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

You probably won’t have a choice next time your boiler needs replacing as gas versions will be banned but yes, hopefully they’ll be significantly cheaper by then.

I've got the feeling all these dates will be postponed in the end...
How much more electricity will be needed if every household went fully electric? So, heating, cars etc... how many new power stations (or equivalent renewables) will be needed per year to get there?

The dates are likely to remain.
Until after the election....

mully79

Before considering a heat pump, ask what refrigerant is used ?
80% of heat pumps installed in 2019 used r410a which is now being phased out as of Jan 23.

I think they’re moving to R32 which cant be used as a straight replacement in a r410a system so those old 2019 heat pumps would have to go in the skip so everyone can have a shiny new lower gwp version.

orraloon

Isn't there a fundamental design conflict problem, in that gas / oil fired boilers can push out CH water at x temp while heatpumps air or ground produce lower temp outflow. So need radiator sizes and pipe systems able to cope with higher flow and lower temps to generate similar room heating effect?

Hence if one's house's design is from the fossil fuel supply times, swopping to a heatpump ain't that simple. Not just ditch the gas boiler for a heatpump.

rjsterry

orraloon said:

Isn't there a fundamental design conflict problem, in that gas / oil fired boilers can push out CH water at x temp while heatpumps air or ground produce lower temp outflow. So need radiator sizes and pipe systems able to cope with higher flow and lower temps to generate similar room heating effect?

Hence if one's house's design is from the fossil fuel supply times, swopping to a heatpump ain't that simple. Not just ditch the gas boiler for a heatpump.

Broadly, yes. Fabric first - reduce the amount of heat you need whatever the source. Then think about changing the heat source.

pep.fermi

orraloon said:

Isn't there a fundamental design conflict problem, in that gas / oil fired boilers can push out CH water at x temp while heatpumps air or ground produce lower temp outflow. So need radiator sizes and pipe systems able to cope with higher flow and lower temps to generate similar room heating effect?

Hence if one's house's design is from the fossil fuel supply times, swopping to a heatpump ain't that simple. Not just ditch the gas boiler for a heatpump.

No radiatiors in our house already.

pep.fermi

Pross said:

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

You probably won’t have a choice next time your boiler needs replacing as gas versions will be banned but yes, hopefully they’ll be significantly cheaper by then.

Yup. I think this is true. Just, my previous boiler is 40yr old and running.

pep.fermi

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

I think this nails it.

rjsterry

pep.fermi said:

Pross said:

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

You probably won’t have a choice next time your boiler needs replacing as gas versions will be banned but yes, hopefully they’ll be significantly cheaper by then.

Yup. I think this is true. Just, my previous boiler is 40yr old and running.

The difference in performance between a 1980s boiler and a 2020s boiler is significant, so just a straight replacement will help. I don't think heat pumps have ever been something you install to save money. The point is to remove the reliance on gas and reduce emissions. If you have a large south-ish facing roof, you can also more easily offset the energy used to run a heat pump with some PV panels.
£40k sounds very high but without knowing the building I don't know if it's justified. We would normally budget something closer to £10-£15k, but demand is high at the moment. If you have £40k to spend, I'd still look at where you can upgrade the fabric alongside any replacement of the old boiler.

Pross

rjsterry said:

pep.fermi said:

Pross said:

ugo.santalucia said:

On a general note, I really don't see the incentive in this, unless your sense of guilt for burning fossil fuels in your very home prevents you from sleeping at night.
I don't think you will ever recover your money in your lifetime and most likely you will end up with a system which is less good at doing its job.
Will it make the house more marketable? Maybe, maybe not, but I don't think right now anyone will pay premium for that and in ten years they still won't because it will be an obsolete heat pump

You probably won’t have a choice next time your boiler needs replacing as gas versions will be banned but yes, hopefully they’ll be significantly cheaper by then.

Yup. I think this is true. Just, my previous boiler is 40yr old and running.

The difference in performance between a 1980s boiler and a 2020s boiler is significant, so just a straight replacement will help. I don't think heat pumps have ever been something you install to save money. The point is to remove the reliance on gas and reduce emissions. If you have a large south-ish facing roof, you can also more easily offset the energy used to run a heat pump with some PV panels.
£40k sounds very high but without knowing the building I don't know if it's justified. We would normally budget something closer to £10-£15k, but demand is high at the moment. If you have £40k to spend, I'd still look at where you can upgrade the fabric alongside any replacement of the old boiler.

They're not in the UK but still seems very high. Fabric should be OK on a 2019 built house you would hope. I don't quite get the reference to a 40 year old boiler but I assume that must have been in the previous house.

rjsterry

Good spot. If 4 years old you may as well get the use out of it.
There's quite a gap between 'complies with the regulations' and 'ideal for a heat pump'.

mark.oneill19

First time poster/long time lurker

ASHP/GSHP - The efficiencies offered by such systems are very good - anything from 3 - 6 times+ kWh output to the kWh input. However, the heat energy out is much lower temperature than that of the hot water provided by a traditional gas fired boiler or from direct electric heater. Therefore you need a large emitter (radiator) to provide the same level/rate of heat transfer of a typical GCH + wet radiator system. Consequently the HP system is likely going to need to work longer and harder to provide the same levels of human thermal comfort you are used to if you don't have oversized radiators or UFH to emit the heat over a large area. Ultimately HTC is the thing that matters.

Modern property, post 2002, probably provides the necessary thermal performance in terms of insulation but also air permeability (how drafty the place is). Older properties are gash - poor fabric insulation and notably leaky i.e. they bleed warm air from the interior to the colder exterior quite readily. The consequence of this is that the indoor temperature drops easily and the heating system then has to switch on to maintain the desired temperature. Your traditional GCH will do this far quicker than a HP, and therein lies the issue - you 'feel' the temperature differential. And the larger the room the bigger the volume of air to heat to the desired temperature and the more heat energy required to achieve this.

If I was considering switching from GCH to ASHP (which I'm not - new high efficiency boiler and wet UFH combo) I'd do fabric first - roof, walls (where possible) and definitely glazing (u-values are really poor and heat loss high) internal ceilings, then I'd get my property tested for heat loss/leaks - infrared survey and air permeability test, addressing any issues as they present themselves. Ill-fitting doors, windows and other building envelope opening are a massive cause of heat loss. Then do nothing for a bit and see what impact that has on heat demand/energy consumption/bills compared with previous periods. Next it's consider a new high efficiency condensing boiler. No point keeping 80% efficient boiler if you can easily replace it with a 95% efficient one and run it for 10 years+ (15% saving straight off). Then do the comparative analysis between that new on paper set up versus an ASHP over the lifetime of the systems. Bear in mind you will likely have an external invertor 'box' that will be at the mercy of the elements - it will rot particularly if you are in a coastal location.

I can't comment on the costs of the OP's HP system - that would be property dependant, but £40k seems high for a typical residential property instal - maybe its a big country pile.

The take away is don't rush into HPs. They are not the silver bullet people think they are. They operate best in well insulated, low permeability property where the heat can be slowly built up and retained. They will not warm your home in the same way as a conventional GCH set up.

Bottom line - insulate well, use less energy overall and save on the bills........or get on the turbo to warm up

Pross

I'm thinking of getting a survey done to work out where we can improve our insulation. There are a few obvious ones - roof insulation is nowehere near current standards but its a bit problematic as we use it for storage so would presumably need to lay batons to get sufficient insulation and allow for re-boarding (the area we can use for storage is already very limited due to a shallow roof pitch). Second we need to replace our windows and doors, I've lived here over 20 years now and other than the front door we haven't replaced anything and the curtains visibly move on windy days. Then theres the conservatory that is seprated by a large patio door that is generally open as it provides access to the garden and the extension I've mentioned before that used to be a garage and is single block clad with foil backed plasterboard which is where I spend most of the day working, that's seperated from the kitchen by an internal door. In an ideal world I would demolish the conservatory and former garage then have them rebuilt as insulated cavity walls but financially that unfortunately isn't realistic.

Our boiler feels new and efficeint but in reality is now over 10 years old so we could probably get something better. I would also like to replace all the radiators that I assume are the originals from the early 70s (plus the pipework could probably do with upgrading as we've had a couple of leaks). Not sure if the radiators would greatly improve efficiency but we could certainly get something less bulky and have them in better locations. However, as above and RJS always says we need to stop the heat leaking before looking at the source of the heat.

surrey_commuter

mark.oneill19 said:

First time poster/long time lurker

ASHP/GSHP - The efficiencies offered by such systems are very good - anything from 3 - 6 times+ kWh output to the kWh input. However, the heat energy out is much lower temperature than that of the hot water provided by a traditional gas fired boiler or from direct electric heater. Therefore you need a large emitter (radiator) to provide the same level/rate of heat transfer of a typical GCH + wet radiator system. Consequently the HP system is likely going to need to work longer and harder to provide the same levels of human thermal comfort you are used to if you don't have oversized radiators or UFH to emit the heat over a large area. Ultimately HTC is the thing that matters.

Modern property, post 2002, probably provides the necessary thermal performance in terms of insulation but also air permeability (how drafty the place is). Older properties are gash - poor fabric insulation and notably leaky i.e. they bleed warm air from the interior to the colder exterior quite readily. The consequence of this is that the indoor temperature drops easily and the heating system then has to switch on to maintain the desired temperature. Your traditional GCH will do this far quicker than a HP, and therein lies the issue - you 'feel' the temperature differential. And the larger the room the bigger the volume of air to heat to the desired temperature and the more heat energy required to achieve this.

If I was considering switching from GCH to ASHP (which I'm not - new high efficiency boiler and wet UFH combo) I'd do fabric first - roof, walls (where possible) and definitely glazing (u-values are really poor and heat loss high) internal ceilings, then I'd get my property tested for heat loss/leaks - infrared survey and air permeability test, addressing any issues as they present themselves. Ill-fitting doors, windows and other building envelope opening are a massive cause of heat loss. Then do nothing for a bit and see what impact that has on heat demand/energy consumption/bills compared with previous periods. Next it's consider a new high efficiency condensing boiler. No point keeping 80% efficient boiler if you can easily replace it with a 95% efficient one and run it for 10 years+ (15% saving straight off). Then do the comparative analysis between that new on paper set up versus an ASHP over the lifetime of the systems. Bear in mind you will likely have an external invertor 'box' that will be at the mercy of the elements - it will rot particularly if you are in a coastal location.

I can't comment on the costs of the OP's HP system - that would be property dependant, but £40k seems high for a typical residential property instal - maybe its a big country pile.

The take away is don't rush into HPs. They are not the silver bullet people think they are. They operate best in well insulated, low permeability property where the heat can be slowly built up and retained. They will not warm your home in the same way as a conventional GCH set up.

Bottom line - insulate well, use less energy overall and save on the bills........or get on the turbo to warm up

A very informative first post but if you want to fit in here then the addition of a shonky graph would not go amiss

Pross

surrey_commuter said:

mark.oneill19 said:

First time poster/long time lurker

ASHP/GSHP - The efficiencies offered by such systems are very good - anything from 3 - 6 times+ kWh output to the kWh input. However, the heat energy out is much lower temperature than that of the hot water provided by a traditional gas fired boiler or from direct electric heater. Therefore you need a large emitter (radiator) to provide the same level/rate of heat transfer of a typical GCH + wet radiator system. Consequently the HP system is likely going to need to work longer and harder to provide the same levels of human thermal comfort you are used to if you don't have oversized radiators or UFH to emit the heat over a large area. Ultimately HTC is the thing that matters.

Modern property, post 2002, probably provides the necessary thermal performance in terms of insulation but also air permeability (how drafty the place is). Older properties are gash - poor fabric insulation and notably leaky i.e. they bleed warm air from the interior to the colder exterior quite readily. The consequence of this is that the indoor temperature drops easily and the heating system then has to switch on to maintain the desired temperature. Your traditional GCH will do this far quicker than a HP, and therein lies the issue - you 'feel' the temperature differential. And the larger the room the bigger the volume of air to heat to the desired temperature and the more heat energy required to achieve this.

If I was considering switching from GCH to ASHP (which I'm not - new high efficiency boiler and wet UFH combo) I'd do fabric first - roof, walls (where possible) and definitely glazing (u-values are really poor and heat loss high) internal ceilings, then I'd get my property tested for heat loss/leaks - infrared survey and air permeability test, addressing any issues as they present themselves. Ill-fitting doors, windows and other building envelope opening are a massive cause of heat loss. Then do nothing for a bit and see what impact that has on heat demand/energy consumption/bills compared with previous periods. Next it's consider a new high efficiency condensing boiler. No point keeping 80% efficient boiler if you can easily replace it with a 95% efficient one and run it for 10 years+ (15% saving straight off). Then do the comparative analysis between that new on paper set up versus an ASHP over the lifetime of the systems. Bear in mind you will likely have an external invertor 'box' that will be at the mercy of the elements - it will rot particularly if you are in a coastal location.

I can't comment on the costs of the OP's HP system - that would be property dependant, but £40k seems high for a typical residential property instal - maybe its a big country pile.

The take away is don't rush into HPs. They are not the silver bullet people think they are. They operate best in well insulated, low permeability property where the heat can be slowly built up and retained. They will not warm your home in the same way as a conventional GCH set up.

Bottom line - insulate well, use less energy overall and save on the bills........or get on the turbo to warm up

A very informative first post but if you want to fit in here then the addition of a shonky graph would not go amiss

And a Twitter link with no context.

mark.oneill19

No can do a shonky graph, I’d need to charge you a fee for that. 😁