Is heat pump technology improving or getting cheaper?

chrisgeller

Interested to hear everyone's thoughts on this.

Seems that heat pumps are the great hope for getting the population off burning fossil fuels, but there isn't much take-up for some practical reasons.

From what I've read, getting an air source heat pump installed along with changing all your radiators in an existing property can easily cost over £10k (which a government grant can help with). You're then left with what seems to be a fairly large, potentially noisy piece of equipment, that is slower to heat up, can't produce hot water on its own, and will probably still cost more in electricity than a gas alternative. I've heard they're anecdotally more likely to break down.

I've heard that there are new refrigerants being used that can get water much hotter, but then the COP seems to fall. At least this might avoid having to change all the radiators, but obviously ongoing costs may be higher.

It looks like ASHPs make some sense on new-builds where you can insulate the hell out of them from the get-go and put in underfloor heating, but that doesn't really help with the pre-existing 30,000,000 homes or so in the UK.

Are we anywhere near a point where the average punter would consider getting an AHSP installed on purely cost/ease-of-use considerations?

Or is it unlikely the technology can get to the point of this any time soon without vast government support?

Reed_Richards

I am replacing an oil boiler with an ASHP soon.  The cost will be a good deal greater than £10k; I have to replace most radiators and also the hot water cylinder because you need a higher output coil inside the cylinder in the same way that you need higher output radiators.  But it should heat the water in the cylinder to 50 C without assistance.  By all accounts it will not be as noisy as my oil boiler is when it is running.  My oil boiler had a service contract and we were averaging about two service calls a year so I hope the ASHP will prove more reliable than this.  I'm told that ASHPs are reliable but then the salesmen would say that, wouldn't they?  The laws of physics dictate that if you heat the water hotter then the COP will fall.
The ASHP only makes economic sense because of the RHI payments I expect to get.  These, I'm told, are set to make up the cost difference between the heat pump and a conventional boiler.  So I am relying on the "vast government support" you mention.  However as with other "green" technologies, costs may fall over time.  


  

Martyn1981

Heat pumps are very popular in Scandinavia, and my house (though admittedly they are just small air to air units), so I don't think there is any real problem with the technology, more the application in the UK, and our particularly poor housing standards. Bit of a shame really, but I'm sure we'll do the right thing eventually ....... once we've exhausted every other possibility.

michaels

I have tried really hard but even with a 10k green home grant and needing to replace a gas boiler I just can't make the maths work with any sort of realistic estimate of the SCOP. Our use case is poor because we use about 5x as much hot water than our epc suggests even though our heating is OK although again we heat 24/7 not the epc 8 hours per day.

Bottom line leccy costs 5x more than gas per kWh so the maths can't work.

Pile_o_stone

michaels said:

I have tried really hard but even with a 10k green home grant and needing to replace a gas boiler I just can't make the maths work with any sort of realistic estimate of the SCOP. Our use case is poor because we use about 5x as much hot water than our epc suggests even though our heating is OK although again we heat 24/7 not the epc 8 hours per day.

Bottom line leccy costs 5x more than gas per kWh so the maths can't work.

I don't think heat pumps will beat mains gas in cost, and if we start piping wind/solar generated hydrogen to replace natural gas, then it never will.

Cardew

I don't know what conditions must be met to get the RHI subsidy. I assume oversight of qualification for the subsidy would be similar to the MCS registration requirement for those installing solar PV??

In the past manufacturers sold a heat pump to an installer, and manufacturers took no responsibility for any problems with a faulty installation.

joefizz

Pile_o_stone said:

michaels said:

I have tried really hard but even with a 10k green home grant and needing to replace a gas boiler I just can't make the maths work with any sort of realistic estimate of the SCOP. Our use case is poor because we use about 5x as much hot water than our epc suggests even though our heating is OK although again we heat 24/7 not the epc 8 hours per day.

Bottom line leccy costs 5x more than gas per kWh so the maths can't work.

I don't think heat pumps will beat mains gas in cost, and if we start piping wind/solar generated hydrogen to replace natural gas, then it never will.

I dont think they will either. I will say though that the air to air ones should really complement a FF system but above all else insulation will be the key. Im visiting a newbuild later on today to get a view of what can be achieved when its designed from the ground up with the end aim to be minimising FF usage, not completely replacing it.

Im currently studying for another masters but its with a US uni so although Im early into the latest module and obviously US teaching will have a different slant to the rest of the world, their answers seem to be going in the direction of nuclear and solar in the main. Certainly where I live we are arent going to get rid of FF completely but we can minimise usage significantly.
One of the resources Im using is the our world in data website. Now again, never take information from just one source but this chart is interesting in terms of uk energy usage.
https://ourworldindata.org/grapher/energy-consumption-by-source-and-region?stackMode=absolute&time=earliest..latest&country=~GBR

Reed_Richards

Cardew said:

I don't know what conditions must be met to get the RHI subsidy... 

You need an accredited heat pump installed by an MCS accredited installer.  You need an MCS certificate from your installer saying that your Seasonal Performance Factor is 2.5 or greater.  You need an EPC that is less than two years old and which does not recommend loft insulation or cavity wall insulation.  Your house cannot be a new build and there are complications if it's not your main home or you have another major source of heating (not just a room heater).    

ed110220

How about air to air heat pumps ie split air conditioners? These are relatively cheap so no government incentives. Obviously you'd need a different way of heating you hot water. Perhaps they're often overlooked as there is an assumption that heating must be a boiler + radiators system in this country, but the preference seems to be cultural.

The other year I went to the Calgary area of Canada where they have bitterly cold winters and I didn't see a single radiator, all the heating was by air vents in the floor or ceiling so direct air heating is certainly viable. 

Reed_Richards

ed110220 said:

The other year I went to the Calgary area of Canada where they have bitterly cold winters and I didn't see a single radiator, all the heating was by air vents in the floor or ceiling so direct air heating is certainly viable. 

The more northerly parts of North America have colder winters and hotter summers than the UK.  So air vents allow heating in winter and cooling in summer (i.e. air conditioning) from a central source ("Central Air").    

ed110220

Reed_Richards said:

ed110220 said:

The other year I went to the Calgary area of Canada where they have bitterly cold winters and I didn't see a single radiator, all the heating was by air vents in the floor or ceiling so direct air heating is certainly viable. 

The more northerly parts of North America have colder winters and hotter summers than the UK.  So air vents allow heating in winter and cooling in summer (i.e. air conditioning) from a central source ("Central Air").    

Reed_Richards said:

ed110220 said:

The other year I went to the Calgary area of Canada where they have bitterly cold winters and I didn't see a single radiator, all the heating was by air vents in the floor or ceiling so direct air heating is certainly viable. 

The more northerly parts of North America have colder winters and hotter summers than the UK.  So air vents allow heating in winter and cooling in summer (i.e. air conditioning) from a central source ("Central Air").    

Calgary has a cooler and shorter summer than London (only two months with average highs reaching 20C, compared with London's four) so I doubt there is much cooling, I didn't see any where we stayed, just a large "furnace". It's also one of the warmer places in Alberta - summers in Banff, Jasper etc where they use similar heating are even cooler and shorter. Just saying that there seems to be no technical requirement for heat to be delivered from radiators rather than directly to the air via an air conditioning unit or vent.