Winter is always either here or right around the corner. Advances in wood stove design have made the appliances more efficient for heating compared to the older models. According to Penn State University, a wood stove could provide a massive discount compared to electricity or natural gas.
A wood stove is a major appliance that can present safety issues from the heat that it produces, so keep these temperature questions in mind before purchasing and while operating one.
Related: Pellet vs. Wood Stove vs. Fireplace
How hot does wood burn?
The heat that wood will ignite and the maximum temperature that it will burn depends on the type of wood, the amount of wood, its moisture content, its physical shape and arrangement, and environmental factors.
Forest fires provide a look at the temperature potential of wood heating. Per the U.S. Department of Agriculture, the hottest forest fires reach temperatures over 2,000 degrees Fahrenheit. Controlled wood fires can steadily burn at temperatures that are much lower.
How much heat does burning wood produce?
For cut and dried wood, potential heat is measured in British Thermal Units (BTUs) and usually given in BTUs per cord, a unique unit of measurement for firewood equal to a tightly stacked 8′ by 4′ by 4′ cube. Depending on the species of wood, the BTUs per cord can range from 13.2 million to 33.5 million.
Comparatively, a 20-pound tank of propane has a maximum capacity of 4.6 gallons of propane, which provides 91,502 BTUs per gallon for a total of just over 420,000 BTUs. Natural gas BTU production ranges from about 10% less to 10% more than propane. The flames from these gasses burn at temperatures around 3,632 degrees Fahrenheit (2,000 degrees Celsius).
At what temperature does wood ignite?
Like the maximum temperature, the ignition temperature of wood will depend on its physical characteristics and surroundings. For instant ignition without any external flame, the ambient temperature needs to be 1,112 degrees Fahrenheit (600 degrees Celsius).
An environment of 700 degrees Fahrenheit with flames will cause the wood to ignite much sooner. Slightly lower temperatures will gradually increase the wood’s temperature and cause it to combust, though it may take a few hours.
A steady period of temperatures that are relatively mild compared to a full-on wood fire can cause a phenomenon known as pyrophoric carbon fires. The not-quite spontaneous combustion can happen at temperatures as low as 170 degrees Fahrenheit (77 degrees Celsius) if the heat never lets up.
Does burning wood produce dangerous gasses?
Burning wood of any kind will produce carbon monoxide and smoke. As long as the flue is properly funneling the smoke outside, the typical contents of wood smoke won’t cause serious harm. If the stove starts producing more smoke than the flue can handle or the pipe gets clogged, excess smoke can start pouring into the area.
Never burn any wood or paper product that has been treated, painted, finished, or otherwise chemically altered. Those extra chemicals add a range of dangerous byproducts to smoke when burned in a fire, and even a small amount getting into the surrounding space may cause harm.
What temperature can a wood stove withstand?
Wood stoves are typically made from a durable metal like cast iron or a sturdy nonmetallic and low conductivity material like bricks. The melting point of cast iron begins at around 2150 degrees Fahrenheit or 1175 degrees Celsius.
Localized deformation and damage will start to occur instantly closer to 1500 degrees Fahrenheit, or 815 degrees Celsius. More subtle damage can occur if the stove runs at high temperatures for an extended period of time.
For normal operation, the ideal temperature is between 270 degrees and 460 degrees Fahrenheit. Most stove thermometers will cover a range from 100 degrees to just under 1,000 degrees. Some include handy guides for the desired temperature range.
Venturing above 460 degrees from time to time won’t harm a well-made oven, but it does reduce the efficiency of the burn for lower total heat delivered from the same amount of wood. Just as elevated temperatures can cause wood fires over time, running the stove too hot can cause heat stress and damage it.
Can a wood stove be too cold?
Don’t run the stove too cold, either. Under 270 degrees, a material in the smoke called creosote can condense and cling to the stove and flue. Over time, that residue builds up into a layer of flammable gunk. If it ignites, it can cause damage to the stove or spread the fire.
Even when the temperature is managed to near perfection, some creosote will build up in a wood-burning stove. Scheduled cleaning is a must, but I try to maintain the temperature, so I don’t have to do it as often.
How hot does the outside of a wood stove get?
Be careful when running a wood stove at any temperature. Both iron and steel start to glow red when their temperature reaches 900 degrees Fahrenheit or 460 degrees Celsius.
Long before that, they begin to heat up to temperatures that can easily cause instant damage to the skin on contact. A giant blister will ruin any comfort that a homey wood stove brings.
With a bit of work, it’s possible to add bricks or other insulation around a wood stove to make it harder to accidentally touch the surface. Bricklaying isn’t a difficult DIY task, but it can still be worth it to have a professional create sturdy surroundings for a stove. Don’t box it in too tightly if you do, either, or it’ll be much harder to service or replace.
The moving air inside the stove carries heat with it, which means that the flue – the pipe leading out of the house – will also have a higher temperature.
It doesn’t get nearly as hot as the inside of the stove, and it can sometimes be beneficial to make the pipe trap more heat to better draw out the smoke from the fire and prevent the buildup of creosote. Still, it shouldn’t be directly touched while the stove is operating, especially the portions closer to the stove itself.
The radiating heat from the stove is also a major fire hazard if not properly installed. The Insurance Information Institute‘s recommendations are a solid starting point for safely using a wood stove or other fire features.
Skimping on the clearance distance and fire-resistant base can lead to fires and might place the fault for a fire on the homeowner. For the full details, the National Fire Protection Association publishes standards for fire safety that include wood stoves.