@hughf Hi.. just read your comment and the last line caught my attention and if I understand you correctly  .. so many years ago I did a self install of a Trianco Active Air Heatpump .... it was a rebadged  chinese made machine anyway the compressor failed I can't now remember if it was in warranty or just out. The point was that as I was not an "approved installer" the manufacturer "Trianco" would not even talk to me or assist in any way.  Ended up scrapping the unit and now happy with air to air. But moving to G2 listed Farmhouse in Somerset in two weeks so its  full circle for me back to oil :)        

That's unfortunate, but the nature of the beast with any sort of refrigeration in a domestic environment over here. Look at the US, HVAC tech's everywhere, perfectly capable of changing all the parts inside your average split ac/heatpump unit. Compressors, 4 way vavles, expansion valves, filters, all available from the spares suppliers or kept on the van.

To be honest, I like to write down my tech at a reasonable rate, so if I can get 10 years out of something that costs £3k, I'm happy with that. I wouldn't expect any issues within 10 years, perhaps a regas, but that's easy enough for anyone with F-gas to do.

I'm not installing it with a LLH or a Plate

You may have seen the discussion on these, both in the thread I started about my installation, and elsewhere. One interesting point is that Freedom changed their requirement for these, from being and absolutely essential component (bye bye warranty if not used etc) to, in their latest installation manual, it being shown as a component, but the warranty voiding aspect if not used has been removed.

I still have my PHE in place, and am still on the fence about it, pros (keeps rad circuit crud away from primary ASHP circuit) and cons (extra expense, losses and something else to go wrong).  

It's really odd that Midea won't sell to end users, even if no warranty was offered. I'd be happy to buy one if they knocked some coin off for warranty voiding - I'll void it anyway as I'm not installing it with a LLH or a Plate - ain't got the space for that, I'll just use the overly long loops of 28mm...

It goes without saying, use is entirely at user's risk, if you turn your house into a freezer of a frying pan using the calculator, it is your responsibility, not mine. But, in the right hands, it might be of use to some people, if only as an independent sanity check.

@hughf - I think various people have been borrowing other people's calculator spreadsheets and modifying them over the years - just as I have done with the OFGEM calculator. If the spreadsheet is available online, that is what will happen (and it is basically a good thing, openness and transparency and not to mention error checking etc). Freedom made their calculator available online, ie put in the public domain, so, as I see it, it is available to all. I suspect many installers also send property/quote specific copies to their customers, again increasing general circulation.  

I can't see the merit in installing a new gas combi, only to find in 2035 that we can't find a replacement when that fails. Plus, it would be nice to ditch the gas finally so I don't have to bother a gas safe engineer and try and ninja a 28mm gas through the house to the new boiler location.

Attached are my latest workings using the Freedom toolkit. At the moment I'm torn between a Midea (concerned by the fact they might not sell me one), a Cool Energy CE-iVT9 (concerned by the efficiency using r410 vs r32 - I don't know enough about the finer points of refrigerants to assess this), and an LG Therma V (because the controller looks excellent, I like the look of the AI weather comp mode, and they're cheap as chips)

@hughf, welcome to the forums and look forward to hearing how your system comes along and which ASHP you chose. I’ve created a dedicated thread for you, so please continue to share updates here.

Thanks for creating this thread for me Mars, appreciated...