Thats not necessarily true bear. I have a heat pump, electric resistance plenum heat, propane and a wood stove/fire place for house heating options in my home. Because of a program through my power company i can heat my house for .064/kwh. At that rate propane has to be below $1.42/gal before the propane furnace is cheaper than the plenum heat (currently propane is cheaper than electric plenum when below 35 deg). The heat pump is about 250% efficient relative to the electric plenum heat which means propane would have to sell for $.57 per gallon in order for it to be cost effective vs my heat pump. But the heat pump can only reach that efficiency above 35deg.
I'm in commercial, industrial and institutional hvac. NY is chock full of natural gas. Without incentives or programs all things being equal natural gas is by far the best value around here for an automatic heating system, I never mentioned propane because it is around 3x the cost.
Ive heard the midwest has the best propane prices. Im in Mn and i heat my 3700' house for $190-230/month with electricity in the cold months. If its 35-40 deg the HP can handle the whole load for about $1 per day. Im happy with that.
And in NY air cooled heat pumps cannot handle the low ambient temps. We use heat pumps in hospitals offices and nursing homes that are cooled by a chilled water loop and heated by a hot water loop (by gas boiler). I don't know why somebody keeps downvoting me.
Second part: you're a "global warming" imbecile. Look it up.