Heating with Firewood

February 2, 2024 · 4 minute read
Heating with Firewood

While the temperatures last week and weekend had us all hoping for an early Spring and getting ready to start gardening, we still have at least one month of likely frigid temperatures to withstand.  I have an old house that has zero insulation in the walls so my house can get quite cold when the temperatures go below freezing, which in turn means my city gas bill will balloon.  I am however lucky to have a home that was built with a wood-burning fireplace and being an arborist, I would be foolish not to take advantage of an almost endless supply of wood.  On cold days and nights, I will keep my fireplace insert packed with wood and slowly burning which can fully heat my old brick four square home.

But I wondered, is it all too good to be true?

My biggest concern is whether or not I am doing more harm than good by burning wood to heat my home. My house is usually heated by my gas hot water boiler and large cast iron radiators in my house. It’s great heat but it surely isn’t efficient. As I considered the pros and cons of supplemental wood heat, I came up with some important considerations.

First, and most importantly, the wood I am burning has been removed for one purpose or another and is a waste product of our work.  The wood that I am cutting and burning is pulled from a supply that would otherwise go to mulch manufacturing or to Dominion Power to burn in their coal-powered plants. In my estimation, this means that I am not only limiting my fossil fuel consumption but also offsetting it with a renewable waste product. Quickly, the math made a lot more sense but I still worried about the health and environmental impacts of burning wood in my home.

Open combustion of wood is smoky, and smoke and particulate matter are not good to breathe indoors or out. Think about a campfire and how irritating the smoke is. This smoke is a small particulate matter made up mostly of tiny bits of improperly combusted material. This is bad for your lungs and can also be quite dirty. Open fireplaces usually produce the most smoke and really do not help much with supplemental heating as they draw too much air up the chimney, offsetting the air with cold air from the outside. I instead have a contemporary cast iron insert in my fireplace that creates a much cleaner burning environment. It produces more heat, limits excessive draft up the chimney, and most importantly, keeps the smoke in the firebox and up the chimney, keeping my house cleaner and my lungs healthier.

It should be noted that an enclosed wood-burning appliance works much better for heat as the thermal mass of the cast iron will keep the firebox much hotter, allowing for a more complete combustion of the wood and less smoke out of the chimney. Today, all wood-burning appliances also come with an internal catalytic converter that will further reduce emissions.

I also started paying close attention to my wood as I have found over the years that age and species matter quite a bit. When it comes to firewood in the Mid-Atlantic, Oak is king. It is a plentiful genus in the area, is easy to split, and provides quite a bit of heat for its mass. I have always been particular to Oak myself as it produces the sweet distinct smoke that we all know and love from fires. It also burns quite cleanly and does not leave much residue in terms of ash in the firebox and creosote in the chimney. Oak has always been my go-to for firewood -especially Chestnut Oak- as it is the easiest to split by hand. Everything changed this year as I tried Black Locust for the first time.

I had always heard that Black Locust was a good firewood but had never had the opportunity to try it myself until a project this summer put lots of Locust logs in our wood yard.  I don’t think I will ever go back. While the Oak creates a hot and relatively long burning fire, Black Locust burns for nearly twice the length of time as a similarly sized Oak log. A firebox filled with Locust at 9:00 at night will still be burning with bright orange dense embers at 7:00 in the morning, making the morning fire much easier to stoke. The only drawback is that we are not blessed with a plethora of Black Locust in the area so it is a harder firewood to source.

The final consideration for firewood is timing. In the best-case scenario, you are splitting wood in the winter of the year prior to its use. Well-seasoned wood not only burns better but is also much cleaner. Seasoning is simply aging the wood long enough to allow adequate water to evaporate out of the wood. If not enough water is removed, much of the heat produced by the burning wood is used to boil off the water in the wood before the wood itself can burn. This results in a cold dirty fire if you can even get the wood to stay alight.

I love a good wood fire inside or out and the warmth and glow that it creates draws people together to socialize on cold evenings and winter days. After putting some thought into the pros and cons of supplemental wood heat, it becomes clear that it is a net benefit for myself and done correctly, the environment. If you are so blessed as myself to have a working fireplace, think about if you could use firewood to help stave off the chill on cold winter nights.