Heating Loads, Simplified

This calculator uses transparent per-square-foot usage benchmarks derived from typical U.S. consumption data: about 0.45 therms of natural gas per square foot per year at average insulation — 900 therms for a 2,000 sq ft home — with electricity (6.0 kWh/sq ft) and heat pumps (2.1 kWh/sq ft, reflecting ~3× COP) scaled accordingly. The season length simply pro-rates the annual figure.

Fuel Choice Is the Biggest Lever

At current typical prices, natural gas and heat pumps are the cheapest ways to heat a home, electric resistance the most expensive, and propane and oil in between. Because each fuel uses a different unit — therms, kWh, gallons — comparing them on dollars alone is the honest way: enter each fuel's local price and compare the season totals side by side.

Insulation Multiplies Everything

The Advanced Options insulation setting shifts usage by −22% to +35%. Air sealing and attic insulation are the classic high-return upgrades precisely because they cut every fuel type at once. A poor-to-good insulation improvement on a 2,000 sq ft gas home saves roughly $200–250 a season — every year, for the life of the home.