Firewood Calculator

Ordering the right amount of firewood for the heating season is a balancing act. Buy too much and you tie up storage space while logs sit long enough to spoil; buy too little and you risk running out mid-winter, when last-minute deliveries get expensive fast. Pinning down your real need protects both your budget and your comfort.

The estimate runs on a simple BTU-based method. The season's heat need is your square footage times a fixed figure for insulation quality (25,000 BTU per sq ft for good, 35,000 for average, 50,000 for poor) over a five-month season, scaled for the number of months you enter. That total is divided by 20 million BTU per cord for hardwood or 15 million for softwood; there is no separate stove-efficiency factor, climate input or target temperature. The cost line prices hardwood at $400 a cord and softwood at $275, and the gas and electric comparison lines price the same BTUs at $1.50 a therm and $0.15 a kWh. Penn State Extension puts modern wood stoves at 80% efficiency or more and open fireplaces at only 10-20%, so with a fireplace the real need is far higher than the result.

Treat the result as a planning figure rather than a guarantee, since burning habits and the specifics of your stove move actual consumption up or down. Not all firewood performs the same, either: seasoned hardwood delivers the best BTU output and burns cleaner, while green wood wastes heat and leaves creosote in your chimney. Be honest about insulation quality, too, because an optimistic rating leads straight to ordering less than you actually burn.