I think people who consider running miner as heater and consider solar as free power may have the wrong mindset.
You might make $70 a years with a nano using limited excessive solar to mine or using miner as a heat source. However, that's not scalable, not going to change your life.
Personally, I have ~10 kw solar. However, I would never consider myself as having "free" power. The solar I have was a bad investment I made a few years ago. It like a drop in ocean for the amount of power I use.
I use at least 10x more power than heating house would require. IMHO, using miner as a heater is not a good reason to mine at a loss. If unprofitable, you save more $$$ if you turn off your miner and switch your heating source from resistance electric to natural gas or heat pump.
Depending on the coin, there is also a lot of uncertainty. Sometimes it's better to wait until bull run, sometimes the coin dies before bull run. Or the coin just becomes forgotten during bull run and never reach previous peak in bear market.
For example, I sold vishai daily when it first came out. If I hodled, it would be worth 0 now.
I mined pyrin before it was listed on the exchange and sold right after exchange listing. It did go up later, but look at it now. I'm so glad I sold all, maybe not at the peak.
