If you burn wood for heat, especially as your primary heat source, you do not want to get up in the middle of the night and load the wood stove! I have heated my home for almost 40 years with a wood burning stove and have never had to get up, before my normal night’s sleep, to load the wood burner. I wanted to read up on what some other wood burning experts had to say about this so I did some research and here is what I found.
Will a wood burning stove remain burning, for a full 8 hour night? Yes, it can, but it takes some planning, and the settings on the stove must be correct to burn a full 8 hours or more. There are some varying opinions on the subject, but the majority of what I have read agrees that a stove will burn for a full night if properly loaded and adjusted correctly.
How a Wood Stove Operates
Fire in any form requires three elements to burn. Fuel, heat, and air. Since the mid-1980s, when wood stove became popular (mainly due to the “energy shortage”), wood burner changed the way we heated homes. Before then, most homes had fireplaces (mainly as a prestige item), and they were used primarily as a gathering place, not a true heat source. They would burn a large quantity of wood in a short time, and most of the heat (about 90%) went up the chimney. The fire pulled large amounts of air from the room where the fireplace was to feed the fire and released it out of the chimney. This air had to come from somewhere, and that was from any leaky window, door, or floor in the home.
A few clever inventors (welders) found that a stove could be constructed of steel, with a sealed door, and the air into the stove would control the fire. By increasing or reducing the air, the wood burner would become hotter or cooler. The efficiency of the stove was increased by 500%. This still meant that 40-50% of the heat went up the chimney, but that was better than the 90% from a fireplace. Less heat was being wasted, and more heat stayed in the home.
The stove was still drawing air from the room to feed the fire but so much less. Is this problem resolvable? The air has to come from somewhere. Just like the fireplace, the air is being drawn from outside the house through leaky spaces in floors or windows. Why not stop pulling the air through the room.
Today’s New Stoves
When an industry starts to grow, of course, the US government has to stick its nose in the pot. Starting in 1988, the EPA came out with its first regulations for wood burning stove manufacturers.
By 1998 those were re-visited, and the regulations were amplified. They were also further defined as to the method of testing. In 2015 the EPA stated that wood burning stoves would only allow an output of 4.5 Grams per hour of PM. This standard will be reduced again in 2020 to 2.0 Grams per hour of PM.
This standard output of PM may change as the Trump administration attempts to reduce regulations. There has already been one step taken to make the testing procedure more consistent. This would, in essence, reduce the 2020 regulations on PM gas emissions.
Of course, the battle between republican (small government, less regulation) and democrat (big government, more regulation) will not end any time soon. The ebb and flow of government will continue to affect the wood burning industry and those of us that burn wood.
What is PM?
PM stands for Particulate Matter. PM is the chemical reaction of large and small particles in smoke caused by the burning wood. These are then carried out of the chimney in smoke. These particles are now required to be reduced by re-burning them inside of the stove. Currently, there are two systems designed to re-burn the PM inside of wood burning stoves.
In stoves that do not re-burn the PM, the particles either escape into the air or collect in the chimney. PM that collects in the chimney becomes creosote. PM that escapes out through the chimney into the air can be harmful if breathed, as is any smoke.
The 2 Types of Stoves
Since these regulations have been in force, two types of wood burning stoves have been developed to meet the EPA regulations. Catalytic and Non-Catalytic. A catalytic stove uses a catalytic device, similar to a catalytic converter in our vehicles, to re-burn the PM before it is sent to the chimney and then released into the atmosphere.
A non-catalytic stove does not use a catalytic device but instead, introduces pre-heated air for combustion over a baffle. The smoke then re-burns over the baffle, and the PM is burned off in this upper section of the stove.
Do Catalytic Converters Affect How long a Stove Burns?
Typically a catalytic stove is as efficient as a non-catalytic depending on the design. Both have to re-burn the PM in the smoke, and both have to meet the same standards set by the EPA. The advantage is there is less heat exiting the home and going up the chimney.
To achieve the burnoff of the PM, the stove does have to reach a minimum temperature (typically 400 degrees F). On the other hand, more heat is gained from the stove by burning off the PM in the re-burn process.
This is where we lose the length of burn we gained by closing the air vent and letting the fire burn at a low temperature for a longer period of time. The new stoves burn hotter and more efficiently, but they burn up the wood quicker.
How Do we make the New Stoves Burn Longer?
Several things can be done to make the fire burn longer. First, when selecting wood for the last fill-up of the day, choose wisely.
Burning hardwood like oak, white ash, hickory, or osage orange wood is always a better choice when burning wood for heat. The denser the wood, the more BTU’s per cord you will get out of it as heat. See my article on The Best Types of Wood to Burn. <Link>
Make sure you have at least some hardwood to burn during the nighttime. Also, pick the largest pieces and place enough wood in the stove to fill it completely. This may be obvious but better stated than not.
Finally, reduce the air supply slightly overnight. You do not have to turn it down completely; just a small reduction will save a large amount of wood. We reduce our stove, so the house cools 2-3 degrees F overnight. I can open my stove doors in the morning after 10 hours and have the fire roaring in 10-15 minutes. The coals that remain will ignite and burn after shaking the ashes to the bottom and piling some wood on top.
Does this create additional PM due to the reduced air to the fire? Probably! Is it worth it to have a full nights’ sleep? Definitely!
A Better Way to Monitor Your Stove
So how do you know when your stove is too hot or too cold. In the past, we all found out when the house got cold, or we walked out to the stove and found it was too low. That little round magnetic thermometer on the stove would read the temperature if you were right in front of the stove. A new temperature sensor made just for wood burning stoves can make this process easier and more convenient.
This sensor will read the temperature constantly, and sent the reading by WiFi to your smartphone. If the temperature is too high, (a setting you can adjust) you will receive an alarm. If the temperature is too low, you will receive an alarm.
Knowing what temperature your stove is at all times will give you the ability to control it better. You can keep it hotter longer. And shut it down when it gets too hot. That gives you safety and control!
Conclusion
Your wood burning stove is a great source of heat and an excellent means of saving money for you and your home. Enjoy the savings in the winter without getting less sleep. Always follow the manufacturers’ recommendations for the use of your stove and use the settings that are suggested.
Monitoring your stove doesn’t mean you have to be in the same room, or even at home anymore. A new tool that can assist in monitoring your stove from anywhere, anytime is available today. Take a look at the Tempsure monitor.