Households in England and Wales to be offered new £5,000 Government grant from April 2022

QrizB

kernowpaul said:

Realistically in my case it appears the most cost effective thing for me to do is replace it with a modern high efficiency electric boiler.
...
Compared against the cost of an electric combi boiler installation ...

Moving to a direct electric heating system will increase your energy use, and your electricity bill, by something like 2x to 3x.

I don't know what your current energy bill is, but for a typical larger property (the sort that I would expect to have a GSHP) that could easily be an extra £3k per year.

Your CAPEX savings on installation will quickly be dwarfed by the additional OPEX running costs.

kernowpaul said:

We have been quoted £18,000 to replace our system,

I'd add that a quote of £18k to fit a £5k piece of equipment in place of an existing one seems excessive. It's a "we're too busy to take your job" quote.

Gerry1

kernowpaul said:

Realistically in my case it appears the most cost effective thing for me to do is replace it with a modern high efficiency electric boiler (We don't have mains gas supply in our area).

Oh dear, the widespread but mistaken belief that anything modern must necessarily be more efficient.  It's often true but it's certainly not the case with resistive electrical heating, everything old or new is always 100% efficient in its energy conversion.

The critical point is that '100% efficient' does NOT mean '100% affordable'.

With a GSHP you've probably been getting around 3 or 4kWh out for each kWh you've put in.  With a shiny modern resistive electric anything you'll always get precisely 1kWh, full stop.  Do the sums.

TheElectricCow

kernowpaul said:

It appears you can't get the grant to replace an existing heat pump, that has come to end of life and requires replacement.

I have bought a property that already has a ground source heat pump, installed about 2007. It is now coming to end of life, and I need to consider replacing it.

Realistically in my case it appears the most cost effective thing for me to do is replace it with a modern high efficiency electric boiler (We don't have mains gas supply in our area).

We have been quoted £18,000 to replace our system, note we already have the ground loop in place, so dont the have the excavation cost of fitting that.

Compared against the cost of an electric combi boiler installation, where is the incentive for people to stay with alternative heating systems. Where the incentive offered doesn't compete with the alternatives.

What does that quote include if you don’t mind my asking? I’m by no means an expert, but £18,000 sounds excessive if a suitable whole system is already in place and all you need is the heat pump itself replaced. 

Electric boiler is probably the worst thing you can do, it’ll be far less efficient than the heat pump so will cost 3-4 times more to run at the same level of heating. 

If keeping the heat pump isn’t an option storage heaters and a suitable new electric tariff are probably going to be the next best thing in terms of cost effectiveness, which on some tariffs wouldn’t be far off gas heating costs anyway.

MattMattMattUK

TheElectricCow said:

kernowpaul said:

It appears you can't get the grant to replace an existing heat pump, that has come to end of life and requires replacement.

I have bought a property that already has a ground source heat pump, installed about 2007. It is now coming to end of life, and I need to consider replacing it.

Realistically in my case it appears the most cost effective thing for me to do is replace it with a modern high efficiency electric boiler (We don't have mains gas supply in our area).

We have been quoted £18,000 to replace our system, note we already have the ground loop in place, so dont the have the excavation cost of fitting that.

Compared against the cost of an electric combi boiler installation, where is the incentive for people to stay with alternative heating systems. Where the incentive offered doesn't compete with the alternatives.

What does that quote include if you don’t mind my asking? I’m by no means an expert, but £18,000 sounds excessive if a suitable whole system is already in place and all you need is the heat pump itself replaced. 

I agree, with a ground source heat pump they could be hitting a COP of 8 depending on if it is borehole or shallow loop, but either of those should be good for several decades more so likely only the pump that needs replacing as you say, which would be nowhere near £18k. Pipes and radiators should be fine, the pumps themselves with fitting would be around £5k. 

TheElectricCow said:

Electric boiler is probably the worst thing you can do, it’ll be far less efficient than the heat pump so will cost 3-4 times more to run at the same level of heating. 

I think the previous poster might have got confused here, an electric heating system is 100% efficient, that is the nature of resistive electric heating, even the heat from the pump will end up in the property. An air source heat pump will hit a COP of around 4, so for every 1kWh of electrical input it can output 4kWh of heat, a ground source system which the PP as should be operating with a COP of around 8, making it the most cost effective heating solution by some way, around 3.4p per kWh of usable heat, wiping the floor even with gas. The only difference is the up front cost of the borehole or laying the shallow loops, but that has already been done and those are good for decades, something installed in 2007 should be good into the 2040s or later. 

TheElectricCow said:

If keeping the heat pump isn’t an option storage heaters and a suitable new electric tariff are probably going to be the next best thing in terms of cost effectiveness, which on some tariffs wouldn’t be far off gas heating costs anyway.

Even in a best case scenario, storage heaters are going to be nowhere near a ground source heat pump in terms of cost, even in the most generous night rate region it would be around three times the operating cost and based on the existing heat pump system just needing the pump replaced installing storage heaters would cost 2-5 times as much as replacing the heat pump, even installing a whole new system would likely be a similar cost for a large property. 

QrizB

I've not seen anyone with a GSHP claim a COP of 8! Most seem to be in the range of 2.5 to 4.

MattMattMattUK

QrizB said:

I've not seen anyone with a GSHP claim a COP of 8! Most seem to be in the range of 2.5 to 4.

One of my cousins has a GSHP, but technically his has interseasonal heat transfer (it works in reverse in summer, air con pumping heat into the ground), so not straight up, from a quick Google it does look like 4.5-5 would not be unreasonable for a fully optimised GSHP though. The major benefit with a GSHP is that their efficiency is pretty constant throughout the year, they do not drop off when the outside temperature drops. 

C_Mababejive

Verdigris said:

C_Mababejive said:

It amazes me that government are happy to spaff taxpayers money on heat pump grants but wont give grants to replace so called zombie boilers which are more than 30/40 years old and deemed most inefficient.

They are. They're encouraging zombie boiler owners to get a heat pump and come into the 21st century. The idea is to phase out gas, not encourage its use.

Bu if i have an ASHP fitted how long will it last? My current boiler has lasted 40 years. Also there are ongoing maintenance costs and the house has to be ripped apart to install lots of pipework and new rads plus a cylinder.

QrizB

C_Mababejive said:

Verdigris said:

C_Mababejive said:

It amazes me that government are happy to spaff taxpayers money on heat pump grants but wont give grants to replace so called zombie boilers which are more than 30/40 years old and deemed most inefficient.

They are. They're encouraging zombie boiler owners to get a heat pump and come into the 21st century. The idea is to phase out gas, not encourage its use.

Bu if i have an ASHP fitted how long will it last?

10-20 years, much like a gas boiler.

Even older than the post you're replying to!

C_Mababejive said:

My current boiler has lasted 40 years.

And is likely to be costing you £2-500 a year more than a more modern boiler would, due to low combustion efficiency. You should really think about replacing it.

C_Mababejive said:

Also there are ongoing maintenance costs

Similar to a gas boiler, then.