Good luck on your journey, @wheatie

I’ve got a lot of time for NIBE, Viessmann and Stiebel Eltron as heat pump brands. NIBE have taken some flak over the past year or two around replacement parts availability, but in terms of engineering and performance they’re still very solid. Don't know much about Thermia, so can’t comment.

Once you’ve narrowed down the brands, I’d say the final decision should really come down to which one your shortlisted installers know inside out. The best heat pump in the world won’t perform if it’s not designed and commissioned properly, whereas a good installer working with a brand they fit week in, week out, will usually deliver better real-world results.

Have you got a shortlist of installers yet?

You mentioned horizontal loops... have you also looked at vertical boreholes? They’re more expensive upfront, but can be more space-efficient and often offer more stable ground temperatures over the long term.

@editor 

Thanks Mars - a little relieved that we are thinking along the right path in terms of manufacturers.

As far as installers are concerned - no, we have not gotten that far as of yet (grateful if you have any contacts in our area).

Our plot is ~6ac, so plenty scope for horizontal loops.

I'll reach out to the above x3no vendors and take it from there.

.....curve ball......we did have a wood burning stove included as part of the overall build, but now thinking it would largely be an ornament and superfluous to requirements for a thermally efficient new build with optimised HP......but welcome your thoughts.

Kind Regards,

W

Posted by: @wheatie

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.....curve ball......we did have a wood burning stove included as part of the overall build, but now thinking it would largely be an ornament and superfluous to requirements for a thermally efficient new build with optimised HP......but welcome your thoughts.

Not a curve ball at all. We have wood burning stoves and if you live is a rural location they can be a lifesaver as we've discovered over the years. Power outages. The stoves are on and we can keep living areas warm. If temperatures drop below design temperatures (which is not that relevant to GSHPs, but definitely applicable to air source units) the stoves come on to help the heat pump. You don't have to use them, but I certainly wouldn't decommission or remove them.

I recommend talking with Kensa Heat Pumps who are a UK GSHP manufacturer.

They're nowhere near you geographically, but actually based almost as far as you can travel west in Cornwall before encountering the Atlantic Ocean.
I say "almost as far" since I'm ignoring a few small islands beyond Lands End... because that would just be Scilly.

Kensa will already have the geotechnical maps for your area of Scotland, and can evaluate four alternative strategies for the ground loop

• sub-surface horizontal pipe runs known as a 'slinky', about 1.5m below ground level
• one or more 'standard' depth boreholes, typically 100-200m deep
• a single deep borehole of approx 400m, which can have significantly greater efficiency
• drop the pipe into a tract of water, such as a river, loch or abandoned mine shaft

They can do a desk-study without visiting your site, but may already have an installer in your area.

Posted by: @transparent

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I recommend talking with Kensa Heat Pumps who are a UK GSHP manufacturer.

Not wanting to spread wild rumours, but I've heard concerns about Kensa's financial stability after they announced redundancy consultations for about 20% of their staff in October 2025 due to policy delays and funding uncertainties in the UK heat pump market. Reports highlighted staff feeling broken by the cuts, a CEO resignation shortly after and some debt mentions, though the company remains active with investor backing and recent project announcements.

Personally, I'd be cautious proceeding with a Kensa heat pump until things stabilise.

I can't speak to Kensa's financial condition, but their kit is excellent and their customer support is OUTSTANDING.

@windyinsancreed They don’t use an AI Chatbot then?😆

@toodles Not at all!  We usually g0t a very helpful Cornishman within 5 minutes who took as much time as needed to talk us through any needed diagnostics/reconfiguration. We had two heat pumps configured to make the most of dirt cheap overnight juice and it took a bit of trial and error to perfect the configuration.

Posted by: @Anonymous

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We usually g0t a very helpful Cornishman within 5 minutes who took as much time as needed to talk us through any needed diagnostics/reconfiguration.

That's quite normal.

Time goes more slowly here in the West Country.  😉