Wood, Oil, and the Luxury of Real Warmth

Wood Fuel vs. Oil Fuel

When comparing wood heat and oil heat, it helps to begin with the basic unit of heating energy: the BTU, or British Thermal Unit.

A gallon of residential fuel oil contains, on average, about 138,500 BTUs. There is not much variation in that number. When we order fuel oil, there is no choice in the matter. We simply get a gallon of fuel oil.

Firewood is different.

The energy available from firewood can vary widely depending on the species of wood, the density of that wood, and whether it has been properly seasoned. Softwoods, such as conifers, produce far fewer BTUs than most hardwoods. Even among hardwoods, the range can be significant. And when firewood is ordered, it is often sold as a mix of hardwoods.

Let’s take hard maple as an example. It is a strong hardwood, high on the BTU scale though not at the very top. A full cord of hard maple — a stack measuring 4 feet by 4 feet by 8 feet — produces roughly 24,000,000 BTUs.

At that level, one cord of hardwood firewood is roughly equivalent to 175 gallons of fuel oil in heating energy.

Now look at the cost.

Here in the Northeast, fuel oil in March was about $5.80 per gallon. Multiply that by 175 gallons, and the cost of an equivalent amount of heating energy comes to about $1,015.

By comparison, a delivered cord of mixed hardwood firewood in this area is currently around $350 to $390.

That is not a small difference.

But there is an important detail here: most delivered firewood at that price is “green” wood. It has been cut and split, but it has not yet been properly dried or seasoned. And this is where the next stage in the firewood process matters.

Firewood does not dry simply because the outside looks dry. The cells inside the wood have to release their moisture. Wood stacked in heaps, sealed under tarps, or stored in a closed building will not dry well — if at all.

If that wood is burned too soon, the heat output will be far below what it could be. The work is the same. The cost is the same. But the result is sub-par.

This is where a breathable woodshed becomes so important. Good airflow, protection from rain and snow, and time are what turn green firewood into real winter heat.

And once the wood is properly seasoned, the value becomes clear.

The numbers show a dramatic price difference between wood and oil. But wood heat offers other benefits too.

Visit homes around here in winter and you will often notice something: the homes heated with wood are usually several degrees warmer than those heated with oil.

That warmth has a different quality to it.

It is not just heat. It is comfort. It is the luxury of bathing in warmth on a cold day.

Firewood is also renewable. Oil is not.

And there is a certain security in knowing that when the power goes out, wood heat keeps heating.

If you live in a cold winter climate, there is wisdom in enjoying winter wherever you can. It can be beautiful — especially when the house is warm.