But you can't power a computer on PV. I don't think anyone who knows something about energy efficient heating suggests PV to warm a house electrically, it's too inefficient.
Not my comment you're responding to, but it's not talking about PV for heating (that'd be kind of ridiculous, honestly).
Systems for heating water/air using solar can be quite inexpensive as well; converting light to heat is rather easier than converting it to electricity.
E.g., I've seen cheap pool-heating systems that just pump the water through wide flattened black pipes exposed to the sun and send it back into the pool. Voila, solar heating!
Yeah my second sentence was a non sequitur, but my point was: you can only do a little with solar/water heating. Yes heating a pool is one of those things, but that's a very niche application. This thread is about heating a house, or at least about being comfortable in one, and solar/water is just not a viable technology for that in the vast majority of cases.
Oh... you said "PV" in both sentences, which is specifically converting light to electricity; that's what threw me.
For heating a house with solar (not PV) -- it would depend on insulation level, I'd imagine. I do know people who use it for "most of the time" water heating, with good results.
