Outside of a good woodstove, there really isn’t a good way to produce heat cheaply. Even solar is expensive up front and can never pay for itself, not even 25 years later.
The best investment is insulation. Insulating the windows and ensuring the doors have good quality seals is some of the most effective means at insulation.
Do you need a system that pays for itself or do you need a system that runs when other systems suddenly break down due to war or national catastrophe? If your system runs when macro systems have collapsed, has not your system suddenly paid for itself?
Another words isn’t the intrinsic cost of self sufficiency
priceless?
Perhaps you might never get back the full cost of a power system in terms of today’s fiat money economies. Consider what you do get back when these fiat money schemes break down!