Welcome to the forum, @callum_62. Glad to see you making an appearance before picking an installer since preparation is a big part of getting a good outcome.

No idea what level of knowledge you have already about heat pumps, but you might want to check out our ABC guide in the articles section of this site. The ABCs of ASHPs: A Jargon-Free Introduction to Heat Pump Basics - Renewable Heating Hub

Although it may be covering basics you're already aware of, it'll be a good way of filling in any gaps in your understanding and may even cover some aspects you haven't yet thought of.

After reading that, you might also want to take a look at another article on red flags to look out for. 6 Red Flags to Avoid When Considering a Heat Pump Installation - Renewable Heating Hub. This article is a useful checklist for helping spot installers taking the easy route rather than the right one for you.

@majordennisbloodnok thanks for this info - I'll give them a read 

I've been doing quite a bit of reading and YouTube videos but I'm in no way an expert and know what I should be getting.

We've had a visit from a heat geek trained company and they came across pretty well - pending quote.  I liked the fact the guy talking to me was also involved in the install 

The quote for 17k was an initial costing from I think more a sales team rather than someone who would be involved in the actual install 

I will be very interested to put a side by side comparison when I have the other quotes 

I'd imagine my house is fairly straightforward too - very new, insulated to a high standard, a fair amount of outside space etc 

If we go ahead we would also consider getting a 2nd battery to bring us up to 13kw if battery storage 

That's good, @callum_62. I also have a solar PV array and, as it happens, Growatt inverter and battery. Whether or not the battery is worth the extra investment is a very difficult question to answer but if you do go for it then the key is making it really work for you. By that, I mean switching to a time of use tariff if you haven't already and putting in some active monitoring of the tariff prices, the battery's state of charge, the heat pump's operational state, the forecast solar production and so forth, and telling the battery to charge from grid at cheap times to tide you over expensive ones. It sounds pretty complicated but it's easier than you might think and there are several ways of doing that. At this stage I won't go into too much detail other than to say it's something you should look into before spending on an extra battery. Once again, if in doubt then just post a question or two here and someone should be able to help.

I'm similar to you, 4 bed, 6.1 solar, 6.4 battery. 

I went with Octopus with 8kw heat pump. £2250 after grant.

I've looked into increasing battery which would cost £890 for another 3.2.

I'm on Cosy tariff with 3 cheap rates throughout the day when I fill up batteries. 

Heat pump hammers the batteries so they don't always last until the next cheap rate that why I enquired about another battery. 

Working out the costs, Cosy cheap rate 12.52p per kw, going sometimes into dearer rates I hit an average of 13.25p per kw throughout January, so overall an increase of just £5 for the month. 

Conclusion, not worth increasing battery.

Well we have all our quotes in and it's really hard to justify going ahead unfortunately 

All quotes at around £15-19k before the grant 

Considering we are in a 5 year old house with very good levels of insulation, windows and doors it's certainly higher than I expected 

Too high to justify the £7500-12000 cost to us at this point in time 

@callum_62 that does seem high. Can you give us an idea of what the quotes cover, including heat pump brands and sizes?

@editor  Hi - sure

Aira 6kw 250l tank - 8 rads changes - £17k

Arotherm 7kw 200l tank 8 rads - £19k

Vaillant 5kw 200l tank 6 rads - just under £15k

All include a variety of radiator upgrades - generally changing any K1 to K2 rads 

My house is bog standard 4 bed detached new build- no weird or complex pipe runs either from what I could tell and they advised - no pipework upgrades were factored.  We already have a system boiler so new tank would go where current tank is

Basic heatloss around 5.2kw

I'm not saying what I've been quoted is overpriced as they come in sort of around the same but I'd have thought our house would have been on the cheaper end of the scale - and yet some are more than the grant and the max interest free loan combined!

Didn't you fancy trying a quote from Octopus?

@njt yes but they are not installing in our area 

It's one of the reasons we might just hold off too

That's unfortunate. 

Hopefully they get to your area in future as they do tend to quote a good price.

@njt @callum 62.  Advert on eBay for Samsung 12kwh R 290 and cylinder, all installed for £2750 + BUS £7500.

My quotes for a similar system plus 13 radiators ranged from £8000 to £15000 + BUS £7500. in rural Norfolk.