Pennsylvania winters don’t ask politely. In Philadelphia, the coldest month averages a low of 26 degrees Fahrenheit, and that single number shapes almost everything about heating a home with wood here: how many cords you’ll burn through, which species are worth the labor of splitting, and how long you need to plan ahead before a log is ready to burn.
How cold it actually gets here
Twenty-six degrees. That’s the average nightly low for the coldest month at the Philadelphia reference station, based on NOAA’s 1991-2020 Climate Normals. Not the record low from some freak arctic blast, and not a daytime high that makes winter feel manageable. This is the typical overnight temperature a Pennsylvania home has to fight against, night after night, for weeks at a stretch.
That number puts the state in a middle zone. It’s not the brutal negative-double-digit cold of the upper Midwest or northern New England, where a furnace failure can turn dangerous in hours. But it’s well below the threshold where wood heat is optional decoration. Twenty-six degrees means real heat loss through walls, windows, and roofs, night after night, for a season that often runs from November into March.
For a homeowner burning wood as a primary or serious supplemental heat source, this figure means the difference between a fire that feels nice and a fire that keeps pipes from freezing. A stove loaded at 9 p.m. needs to still be putting out useful heat at 3 a.m., when the outdoor temperature is sitting right around that 26-degree mark or lower. That’s an overnight burn problem, and it’s a density problem, which is exactly what the next section deals with.
What this means for planning
If you’re heating a drafty farmhouse or an older suburban home with mediocre insulation, this cold figure means wood needs to work hard for four to five months. If you’re supplementing a gas or oil furnace with a wood stove for cost savings and ambiance, the same 26-degree baseline still matters, it just changes how much you lean on the wood versus the furnace on the coldest nights. Either way, this isn’t a climate where a rack of half-seasoned softwood gets you through comfortably. The cold here is real enough that the choices below aren’t cosmetic.
Which woods are worth the effort here
With a winter low around 26 degrees, density starts to matter in a way it wouldn’t in a milder state. A cord is a fixed volume, a stack measuring 4 feet by 4 feet by 8 feet, or 128 cubic feet total. That volume never changes. What changes is how much wood mass is actually packed into it, and denser species pack in more pounds of burnable fuel per cord than lighter ones. More mass per cord means more stored energy, which means a longer, hotter burn from the same amount of stacking and hauling.
According to Michigan State University Extension, a cord of well-seasoned hardwood carries roughly 20 million BTU on average, which works out to about the heating value of 145 gallons of #2 fuel oil or 215 gallons of LP gas. That figure is an average across hardwood species, not a fixed constant, and both species and moisture content push it up or down significantly. A dense, dry cord can outperform that average; a light or poorly seasoned one falls well short of it.
Among species commonly cut and sold in Pennsylvania, red oak deserves specific mention, not for its heat output but for how it behaves in the stack. MSU notes that red oak’s cell structure makes it dry more slowly than most other hardwoods, so it needs extra time seasoned before it earns a spot in the wood shed for a cold night. That’s a scheduling issue as much as a heat issue: buy or cut red oak late, and it won’t be ready when the 26-degree nights show up.
Density versus availability
The densest hardwoods, generally the oaks and hickories sold regionally, are the ones worth prioritizing for the coldest stretches and for an overnight load meant to still have coals in the morning. Lighter woods, birch and similar species, burn faster and hotter at first but don’t hold a bed of coals the way dense oak does, which makes them better suited to kindling a fire or carrying the shoulder-season evenings in October and April than to anchoring a January night.
But none of this matters if you can’t get the wood seasoned properly. A modestly dense species that’s been split, stacked, and dried correctly for a full season beats a theoretically superior dense species that’s still green when the cold arrives. Local firewood dealers and the seasoning timeline described below decide as much of your winter as the species chart does.
| Wood category | Relative BTU per cord | Smoke | Sparks |
|---|---|---|---|
| Dense hardwoods (oak, hickory) | At or above the ~20 million BTU seasoned average | Low when fully seasoned | Low |
| Red oak specifically | Near the average, once fully dried | Low when dry; heavy and acrid if burned green | Low |
| Lighter hardwoods (birch, similar species) | Below the seasoned hardwood average | Moderate | Moderate |
| Softwoods (pine and similar) | Well below the hardwood average | Higher, more creosote-forming | Higher, more popping |
How much wood a winter takes
Any published number claiming “you’ll need X cords in Pennsylvania” is close to useless on its own, because the real answer depends on three things happening in your specific house, not in some statewide average. The 26-degree baseline is only the starting point. From there, everything hinges on how well your house holds heat and how much of your winter heating actually comes from wood versus a furnace or heat pump running alongside it.
The mechanism that moves the estimate the most is insulation. A poorly insulated older home, gaps around windows, minimal attic insulation, an uninsulated basement, can burn through roughly double the wood of a tightly sealed, well-insulated house sitting in the exact same climate and the exact same 26-degree cold snap. That’s not a small variation. It’s the difference between three cords and six for the same winter, the same thermostat setting, and the same species of wood.
Run your own estimate using these variables rather than trusting a flat number:
- Local winter severity: how many weeks realistically sit near or below that 26-degree overnight average, and how long your heating season runs beyond the coldest stretch
- House envelope: age of insulation, window quality, air sealing, and whether the basement or crawlspace leaks heat
- Wood’s role in the system: whether it’s the sole heat source, a nightly supplement to cut furnace runtime, or an occasional-use amenity for a few evenings a week
- Square footage actively heated: a wood stove warming one main living area burns far less than one expected to carry an entire multi-story house
Someone burning wood as the sole heat source in a leaky older farmhouse should plan for the high end of any range they see quoted locally. Someone running a stove a few nights a week alongside a working furnace, in a well-insulated newer build, should plan for the low end, and probably shouldn’t stockpile more than they can actually use and season properly in a given year.
Drying wood in this climate
Seasoning matters more than species, in Pennsylvania or anywhere else, because green wood simply cannot deliver its stored heat until the water inside it is gone. MSU Extension puts green wood moisture content at over 60 percent, while the target for burning is 20 percent moisture or less. That difference isn’t cosmetic. Every bit of that water has to boil off inside your stove or fireplace before the wood starts producing usable heat, and that boiling process eats into the very energy you were counting on.
What actually dries firewood is airflow and time, not direct sun exposure. Wood needs to be split first, since bark and unsplit rounds trap moisture inside for a long time, and then stacked loosely enough that air moves freely between and around the pieces. A tarp thrown directly over a tight pile does more harm than good by trapping humidity against the wood.
Pennsylvania’s summer humidity slows this process compared to a drier climate, so a full summer of split-and-stacked drying is the realistic minimum for most hardwoods to reach that 20 percent target, not a shortcut of a few weeks. Red oak needs even longer than that baseline, thanks to a cell structure that MSU specifically flags as slow-drying, so wood cut this spring intended for the coming winter’s coldest nights is very often not ready when November arrives.
That timing mismatch is the single most common mistake made by Pennsylvania firewood buyers and cutters: assuming a spring cutting will be dry enough for the following winter. Wood meant to burn through a stretch of 26-degree nights should generally have been split and stacked the previous year, giving it a full season or more of airflow before it ever gets close to a firebox.