I think insulation would be the first step regardless of where we live. We had flurries yesterday that didn't even stay on the ground for a minute which means my fishing will have to wait as I like it warm. Been looking at building my own home for years, from advanced framing to insulation, to ground heating/cooling. (With the high water table, cooling would be really simple) My only concern with insulation is moisture and how to prevent mold growth. My water table is high, about 30cm below the grass. Your in floor heating makes me think that a concrete wall with a heating element inside would be a possibility. It would only have to be just above inside temperature in winter.
What you have done is pretty impressive. In my days as an electrician in NZ they still had "night storage heaters" who used a similar concept. The relay would make a loud CLANK sound when it came on whenever the plants had too much spare electricity. The owner could open them up or close them to control the temperature somewhat. I was only doing commercial buildings, office and factories and then mostly mechanical, so I never worked with one. How do you control the temperature, or are you ok with letting it fluctuate depending on how much solar you have? And what did you use for insulation?
Solar+ storage is getting to the point where it makes financial sense for people to go off grid, house price, even here 2 hours from Toronto have increased in price so much that a 30k system is only a fraction of the cost of a home. Add starlink to the mix and it makes sense for people to move to cheaper locations. A self driving electric car would allow you to sleep on the way to the office if you have to attend in person once a week or less and can be charged at home.
It is hard to predict the future, especially when all of it depends so much on personal preference. My new neighbours sold their house in Toronto, she works as a teacher and he works from home as an engineer they have young kids who they spend a lot of time with, it is perfect for them. My wife is a city girl who works from home and she likes a big house, which we could only afford here. While I prefer to be even further away from the city, in a small house (but in a nicer climate, a (push)bike ride away from the ocean) New solar equipment is finally coming down in price, with all in one systems going to give some serious competition to the DSSR20. (Not because they are better, but because they are cheap and convenient) Combined with rack mounted batteries those are going to give the powerwalls a run for their money.
I love what you have created, the fact that it does not waste energy as heat, which has to waste even more energy by trying to get rid of the excess heat and the external IO made it the perfect choice for me, the diversion, while not an option for me, is brilliant. And like all nearly all brilliant solutions, logical in hindsight. I am glad you chose to share it freely.
Below a picture of my 4 panels installed on the shed taken last month. I get sun on them from about 11:30 as there are some large trees to the Southeast, yesterday I got about 2 kWh from them but it was a dark overcast day. I need to paint the ends of the horizontal 2*4's and cable tie the wires (Still testing output per panel as the trees behind partially overhang the shed.)
Next 8 panels will go where the green tarp is, wife wants more shade there, but while I will be building it alone, this time I will get some one to help me lift them up onto the wooden structure. Angle will be far from optimal, even worse than the shed, but I do have to compromise with her and the trees that throw shade on the shed, won't be in the way. I told her don't expect much production over winter, but she is ok with that.