The geothermal hvac unit that I am looking at is a 2.5 -3 kw...

The geothermal hvac unit that I am looking at is a 2.5 -3 kw unit . That unit is capable of doing a 30 square house . Heating , cooling and hot water . The installer has customers who I can talk to and let me look at their power bills so I can see the facts for myself . I am yet to do this . That is obviously a super important part of this whole thing .

Your idea of multiple splitties isn't a bad idea at all . The beauty there is you could probably retrofit an extra one or two if needed . You can get multi head splitties anyway which could work as well .

I've been speaking to a few a/c people recently . Privately they will tell you that in some circumstances , rc heaters won't do the job when it is really cold . The coldest we get here is 0 deg which should be ok but I'm still checking that out . -20 ? I reckon that's pushing it . I know up in the high country they struggle when the temp goes negative .

I have been given a couple of rough quotes for a ducted rc ac system and they start at 15k and depending of the quality of the unit , can go a bit higher than that .

The thing with having solar panels offsetting the hvac system is that most of the time ( during the day ) , there will be nobody home . Early evening for heat/cool is probably the prime time , just when the panels stop producing . Yes , it would make sense to precool/heat the house during the afternoon for free . I'm just wondering how much extra energy is required for that evening/overnight period .

" So are you planning on being off grid and Geo HVAC or one or the other? "

All options are on the table for me . Everyone's situation is slightly different so adapting the technology is where the detail becomes crucial . As you previously posted , when building a new place on acres , 25k is almost negligible . Or the example of the depreciation on a new car .

So , in theory , for 60k I could probably have a total off grid system and a 30 square house that is completely heated and cooled . No power bills ever . Heating and cooling running all day if I choose .

Compared to : 5k for power connection .
15k for ducted rvac .
5k for solar boosted hot water .

Roughly a 35k difference . Less 3k a year for power bills ? Hmmm , the gap is starting to reduce .

Not forgetting solar panel and battery replacement at some point although I expect that the replacements in time will be much cheaper and more efficient so maybe the replacement costs will not be so bad .