Baseline propane usage for a mid-KY winter comes from the ~2,500
heating-degree-day climate of Laurel County. Insulation and setpoint apply
straightforward multipliers (roughly 3% per degree, 22–32% swing between drafty
and tight envelopes).
Propane furnace: baseline gallons × your $/gal price, 90% AFUE
mid-market gas furnace. Electric strips: same BTU load at 1 kWh =
3,412 BTU, priced at your electric rate. Cold-climate heat pump:
HSPF2 ≈ 8.5 — roughly 2.5× COP over a KY heating season.
Dual-fuel: heat pump above ~30°F (about 65% of the season),
propane below — weighted 65/35.
Your actual winter cost depends on solar exposure, air infiltration, ductwork, and
how often the door opens.