How Many Cords of Firewood Do I Need?

I built this calculator because I got tired of guessing. My first winter heating with wood, I ordered three cords of red oak for a 1,800 square foot house in upstate New York. Ran out by the end of January. Turns out I needed closer to five. That’s an expensive lesson when you’re scrambling to find seasoned hardwood in the middle of winter.

The math behind this tool is straightforward. It starts with your climate zone, pulled from NOAA data based on your zip code. That gives us your heating degree days (HDD) — basically a number that tells us how cold your winters are. Then we multiply by your home’s square footage, factor in your insulation quality, and divide by your stove’s efficiency. The result is your total BTU requirement for the season.

From there, the calculator divides your BTU need by the heat output of each firewood species. That’s how you get the cord count. A dense hardwood like Osage Orange at 30 million BTU per cord will go a lot further than white pine at 15 million. You can compare all 70 species on our BTU comparison chart.

Here’s something that surprised me when I first dug into the numbers: the difference between an EPA-certified wood stove and an open fireplace is massive. An EPA stove runs at roughly 72% efficiency — meaning 72 cents of every dollar’s worth of wood actually heats your house. An open fireplace? About 10 to 15%. Most of that heat goes straight up the chimney.

In practice, that means a 2,000 sq ft house in a cold climate might need around 7 cords with an EPA stove, but closer to 35 cords with an open fireplace for the same warmth. Nobody’s burning 35 cords — which is exactly why open fireplaces are for ambiance, not heating. If you’re serious about heating with wood, an efficient stove is the single best investment you can make.

Not sure which species gives you the most heat per cord? Check the BTU comparison chart or use the BTU calculator to figure out your exact needs. And if you want to make sure you’re getting the best bang for your buck, the cost calculator compares species by price per million BTU.