Primer: Heating with Wood

It’s Christmas morning, but the scene is the same as any other time we visit Grandma and Grandpa’s farmhouse. An orange glow shines through the tall, single-pane windows of the small house with a tin roof and brown roll siding. Steady wisps of smoke gently curl upward from a masonry flue in the center of the roof, while a second chimney near the rear of the house works to maintain the same pace. We step inside and are met with a wall of comfortable warmth. Grandpa kneels on one knee in front of the Ben Franklin stove and rearranges the collection of burning wood and embers as I’ve watched him do so many times. Grandma calls from the kitchen, where we make our way through the house and find her methodically drying her hands on her calico apron. Assorted pots and skillets, both cast iron and steel, sizzle and steam on the large cast iron wood cook stove.

It’s been 40 years since that morning, and a lot has changed for the little farmhouse. Grandpa and Grandma have left this life and gone on to their reward in Heaven. But we still visit that farmhouse a few times a year, usually during hay and hunting seasons, and we still rely on the heat from the wood stoves to feed and warm us. For anyone who grew up in the country, or longs for the country life and simple living, heating with cost-effective and efficient wood should be a priority.

My family chooses to heat with wood out of frugality and nostalgia. I thoroughly enjoy spending a cool Saturday morning splitting firewood with a maul out behind the workshop. We heat our home with a wood-fired furnace that pumps the warmth through ductwork to each room. But the comfort of the wood heat, and the savings to the family budget, are every bit as much as it was for our ancestors. In fact, much of the wood I burn comes from woodlots on Grandpa’s, and now my Dad’s, farm. Someday those woodlots will pass to my generation, and I intend to hand them down to my children. I hope they find heating with wood just as enjoyable.

That’s not to say that heating with wood is easy. There’s an old saying that goes “He who cuts his own wood warms himself twice … once when he cuts it, and once when he burns it.” The author of that phrase obviously heated with wood and gathered his own fuel. All good things in life come with a price. Heating with wood is no exception, but using the correct tools and methods, and choosing the right kinds of wood can make it much easier and even enjoyable.

Wood heat is a “green” way to keep your home warm, and even cook your meals if you prefer. Most hardwood timber stands will renew in about 20 to 25 years. Keep in mind it only takes wood from a few trees to heat a home for an entire winter. And oftentimes free wood can be found from cull logs and tops from logging operations, or landowners looking to remove one or more problem trees. I burn a mixture of wood I cut on the farm and buy from other wood cutters. I’m always on the lookout for someone looking to get rid of good wood “if you haul it away”.

But you have to be discriminating and not take a gift of a bunch of soured or poor quality wood. Trees which blow down in summer storms and sit untouched with the sap up in them can quickly “sour” and become nearly impossible to burn. Such wood can be identified by an obvious high moisture content long after it should have been drying out and a sometimes obvious pungent odor. Furthermore, when you try to burn it you’ll discover it’ll sputter and sizzle, and almost put itself out from the amount of liquid seeping out of the core. Also, more ornamental “yard” trees such as silver maple and elm can appear fine but offer less heat by volume of mass than other hardwoods such as hickory or oak.

When it comes down to it, wood is a fuel source that generates “units” of heat just like coal, oil or electricity (the latter which could be considered more a method of storing and transferring energy that can be used as heat). Units of heat are measured in British Thermal Units, or BTU’s. Scientists say one “unit” is the amount of energy needed to heat one pound of water from 39 to 40 degrees Fahrenheit. For the rest of us all we need to know is that the more BTU’s a heat source carries, the hotter something becomes.

Several online resources offer a breakdown of recoverable BTU’s from various species of wood. “Recoverable” means how much heat can be pulled from the burning wood. As a way of comparing apples to apples, or in this case wood to wood, we’ll look at how many BTU’s can be taken from a cord, or 128 cubic feet, of seasoned firewood.

Species – Recoverable BTU’s per cord (in millions)

Hickory – 19.39

Apple – 18.55

White Oak – 17.99

Sugar Maple – 16.8

Red Oak – 16.8

Yellow Birch – 16.52

Paper Birch – 14.21

Cherry – 14

Elm – 13.65

Red Maple – 13.09

White Pine – 10.01

Cottonwood – 9.45

While I included white pine, I certainly wouldn’t recommend it as a heat source. Softwoods such as pines and cedars burn hot and fast and contain a lot of creosote-producing sap. Filling a fireplace or stove with pine could cause the stove to overheat and crack, a steel or masonry flue to be destroyed, and most certainly would result in you waking up the next morning with frost on the inside of the windows because the fire burned out shortly after you started snoring.

If you’re new to heating with wood, or just contemplating switching heat sources, I’d suggest you find a good book or manual on heating with wood. It will provide much more detail than can be had in an article of this length.

As for the right stove or other heat equipment to use for your home, there are a long list of possibilities. Traditional open fireplaces, fireplace inserts, freestanding stoves, furnaces with ductwork, and outdoor wood furnaces are the main choices. There are also stoves and furnaces which burn pelletized wood fiber, sawdust compressed and held together with a binding agent. Consider the layout of your home and the requirements of your insurance provider when choosing and installing heating equipment. We installed a wood furnace in our home in the fall of 2001 and had to assure minimum setbacks from the ceiling and walls, and proper flue installation to satisfy our insurance agent.

If you cut your own wood, knowing the terms for certain quantities is unimportant. After a winter or two you’ll quickly determine how much fuel you need to have on hand to make it through to spring. But if you purchase wood you need to know what to order. Quantities of wood and the names they’re referred to by can change from one region to another. In many places wood is sold by the “rank”, which is a stack of 16-inch pieces standing four feet fall and eight feet long. But sometimes that same measure is referred to as a “rick”. Three “ricks” or “ranks” makes up what is often called a “cord”, or 128 cubic feet of wood. But sometimes a wood cutter will sell only by the truckload, which can vary widely depending on what kind of truck he’s driving at the time.

If you deal with a cutter who only sells by the truckload, I’d suggest you buy the first load and then stack it to assure you’re getting the amount compared to the price that is acceptable for your area. Where I live wood can be bought for $35 a seasoned rank in the fall, and can climb to as much as $50 or more for a green (unseasoned) rank near the end of a long, hard winter. A good firewood cutter will give you the agreed on amount and just a little more for good measure. For several years early in our marriage my wife and I cut and sold firewood for extra income, and we always gave a little extra and quickly built a good customer list.

The only time you should ever burn softwoods is as kindling to get a fire going. I save up and split lumber scraps, primarily white pine, to use as kindling. A hatchet, splitting block and a couple hours one evening or afternoon and I can split enough kindling to keep me building fires all winter long. I put my kindling in five gallon buckets and seal with a lid.

Another important part of heating with wood is getting the fire going. While you can toy with trying to get small pieces of kindling going while standing in there in a cold house, most people prefer some kind of fire starter.

We use manufactured fire starters made of compressed wood fiber and a binding agent. They come in a box of several squares that can be broken along perforated lines into smaller pieces. One or two pieces nestled in beneath a small teepee of kindling works great. I keep a couple boxes of fire starters, a box of matches and a couple lighters in a waterproof storage box sitting near my furnace. My grandma and grandpa chose a simpler, homegrown method. They kept a handful of split kindling pieces sitting upright in an old coffee can half full of kerosene. The homemade version of a kerosene pot, which holds a reusable dipper, always assured a reliable ignition source for the next warming or cooking fire.

Heat with wood any time at all and you’ll find that some species are not as easy to get ignited as others. Woods that light fair to good include ash, white birch, hemlock, elm and hickory to name a few.  Woods that are hard to light include black locusts, beech, cherry, apple, sugar maple and red oak.

Before I end, let me remind you to always maintain a clean chimney. Doing so can be the best hedge against a disastrous fire. I clean the chimney at our house each fall with a simple set of fiberglass rods that attach together to span the length and a flue cleaning brush. A few passes of the brush up and down the flue and a quick inspection with a flashlight and I know the buildup of dangerous creosote is gone for a time. It’s also a good idea to buy chimney cleaning aids that can be thrown in the fire and will help rid the flue of creosote as they burn. These are great for using during the heating season when it might not be feasible to let the fire go out and chimney cool down enough to brush it clean.

The goal here was not to delve into what’s required to cut firewood. That’s an entirely different story and requires too many details than allowed for here.

If you intend to harvest your own wood you’ll definitely need a good axe, a splitting maul, a couple splitting wedges, and some kind of saw to drop any standing trees. Chainsaws are like wood stoves … while the basic design is the same the features from brand to brand vary widely. And if you want to really live the history of man using wood to stay warm and eat, you might want to at some time try your hand at a crosscut saw. Grandpa relied on a chainsaw from day to day, but he also kept his crosscut saws sharp and set and ready for use.

I learned a lot of things from my Grandpa, but I’d have to say carrying on his tradition of heating with wood has been one of the most rewarding … and most warming.

About doug smith

Doug Smith is a small town newspaper managing editor. He has also been a freelance writer for rural living, country life, tourism, and hunting and fishing publications for the past 12 years. He lives in an 1880s Victorian-style home in the Missouri Ozarks. He drives an old pickup truck, tinkers with old tractors, is married to a young woman, they have two beautiful and successful children, and he can be found any given day around town wearing his Buffalo plaid flannel jacket and matching Elmer Fudd hat.