GSHPs are rare in the UK and likely to remain so. In practice building regs will require most new homes to have heat pumps but they'll almost all be air-source units. UK winters rarely get very cold (typical minimum design temperatures are above -5C in most of the country) so ASHPs work well all year.

Even better would be to build out (in new build housing estates at least) district heating. This is common in quite a few other countries and it should work pretty well in the UK too - it's always seemed odd to me that it isn't more common here.

I used to have it; it's a technically nice system when working, but the problem is having no choice of provider, no control when it goes wrong, etc.

Makes sense for flats (or dense area of many leasehold houses, if that happens) where there's a management company holding your throat anyway, but otherwise I can't see how it works unless perhaps it was provided by the council (similar disadvantages, just more trust/better outcomes from complaints).

Plus, don't GSHPs need quite a lot of land for the piping? Houses in the UK are built on the smallest possible plots of land :(

It's normal for temperatures in Scotland to dip below -5C over winter - do ASHPs not work at those temps?

For horizontal designs yes- the rule of thumb is the brine coil area should be around 3x the heated area. However, the vertical bores don't need much area, just expensive drilling work.

I think I can call myself fully corrected. I mistook GSHP for all heat pumps and got confused

New UK houses would all be cavity-wall so is there a reason the inside of the exterior wall isn't being used as the source ?

I'd love to see the source for this info - do you have a link?

Thank you!

I wonder if whoever thought that up has ever been to the UK?

Its a UK government plan so yes, why do you ask?

Also, you know, it's the UK Government's plan, so you know it's going to be something that is deliberately designed to not work, but will funnel billions of pounds of public money into private firms with relatives of Tory cabinet ministers on the board.

If the UK Government appears to be doing something "good for the environment" you can rest assured it's only because they've found a way to use it to siphon money out of the public purse.

Well, it doesn't sound like they know much about the geography or geology of the UK, quite frankly.

How is every house builder going to afford a million quid borehole?

I don't think the original claim is quite right. The UK govt is banning new gas boiler installations after 2025, but I believe there's a range of alternatives such as an air or ground source heat pump, or a hydrogen boiler.

From what I've read through, replacing my boiler with a gshp would cost in the tens of thousands, not a million pounds.

How would a hydrogen boiler work? Hydrogen trucks deliverying? Is the UK piped for hydrogen? Electrolizing water on site?

Somehow all the leaky old cast iron pipes that just about suffice for carrying gas around the country will be able to be used for hydrogen Real Soon Now, and everyone will be able to just go out and buy a new £6000 boiler to replace the natural gas ones they had fitted recently.

Then all we need to do is start turning the natural gas into hydrogen - releasing just as much carbon dioxide as burning it does - and we've got a clean green hydrogen economy!

The plan is to convert the existing pipe network to use hydrogen. British Gas are planning to trial it starting with a village of around 2000 homes next year. Meanwhile modern boilers are often being sold as "hydrogen-ready" in preparation for the switch.

Ground source boreholes are mostly 10-15 metres deep, so not wildly expensive, especially when part of a new construction. You may be thinking of classic geothermal bores? Drilling down to proper hot-rocks would be a much costlier scheme in most of the UK.

Wonder if you could drill centralised borehole and then use retrofit old gas lines to move compressed refrigerant…

> Drilling down to proper hot-rocks would be a much costlier scheme in most of the UK.

Is this something people do?

Big buildings do. They often have to go down that deep for foundation pillars anyway.

You don’t need a borehole at all. Ours uses coils of pipe that are about 1m deep.

So, not really suitable for most of the north-west then.

I skimmed the plan and didn't find any requirement to use a ground to water heat pump. Air to water devices are mentioned several times as viable heat pumps for this plan. These do not require boreholes.

I think the UK is effectively banning gas boilers and its upto the developer/consumer to choose an alternative - a combination of CHP (local heating), GSHP, but most likely air source heat pumps.

Almost all heat pumps in the UK being installed these days are air-source.

Those work in hot dry countries. Lots of the UK - in particular the north-west - is neither hot nor dry.

Up here you end up with the outdoor part freezing into a block of ice.

I live in a similar climate and have never once had this problem in the winter. Something is wrong if this is happening to you.

Every one we've got fitted around sites at work freezes up in the rain. Given that they have to be outside, I'm not sure how to solve that.

Incorrect. Try a quality brand like Mitsubishi or Thermia.

These are all Mitsubishi ones, fitted by the manufacturer's recommended installer.

The problem is that the outdoor part has to be, well, outdoors, and that's where all the water is.

Canadians have air source heat pumps with backups that get used ~5-10 days a year...