I'm jealous of your financial learnings. However, your model is not accurate as it doesn't factor in the 4 degree improvement in comfort and indoor pollution from propane furnaces: Propane furnaces can cause indoor pollution through the release of pollutants like carbon monoxide (CO), nitrogen dioxide (\(NO_{2}\)), and benzene, which are byproducts of combustion.
It also doesn't include the negative externalities because of tragedy of commons. Sadly, these kind of flawed 'financial' calculations are widespread.
What is inspiring from the OPs comment is that this is doable in harsh Canadian winters with negligible solar and it breaks even. Most of the world is living in significantly more sunshine, so it should work out a lot better financially for >99% of the population.
It also doesn't include the negative externalities because of tragedy of commons. Sadly, these kind of flawed 'financial' calculations are widespread.
What is inspiring from the OPs comment is that this is doable in harsh Canadian winters with negligible solar and it breaks even. Most of the world is living in significantly more sunshine, so it should work out a lot better financially for >99% of the population.