How do I get the best burn from my wood burning stove?
Posted by Stewart Mcilroy on 21 February 2017 at 9:55 am
To get the best burn from you wood burning stove, it's vital to use your stove's secondary air supply correctly...
You might be thinking that now you have got your wood burner installed, you can happily burn as much wood as you like safe in the knowledge that you have done your bit for the environment. Well, actually that might not be the case!
For a wood burning stove to efficiently convert wood fuel to maximum heat, the wood burner needs to be operated correctly so as to achieve the additional benefits that are not provided by an open fire. So what does this mean in practice?
Fundamentally for a wood burner to operate correctly you need to burn both the wood itself and the exhaust gases that are expelled during combustion, whereas in an open fire the exhaust gases are expelled from the chimney in an unburned state.
This is why a wood burner is said to be 80% efficient (if operated correctly) and an open fire only 20% efficient, as 80% of the potential heat of an open fire goes up the chimney. Hence, if you don’t operate your wood burner correctly you will lose a lot of heat energy up the chimney and cause more air pollution than if the wood burner was used efficiently.
Managing the primary and secondary airflows
Help is at hand. To burn those exhaust gases you just need to correctly use the two air supply controls on your wood burning stove which control the primary and secondary air flows. The primary air supply arrives below your fire while the secondary air supply arrives in the form of air jets above your fire. The secondary air flow is the most important for achieving combustion of the exhaust gases.
Use the primary air supply to get the fire going and burning hot, then shut it down. From this point on manage the fire by adjusting the secondary air flow.
If this is done correctly you will see the flames dancing around and little jets of gas burning as they exit the wood. Another way to know you are getting a high level of secondary combustion is that your logs maintain their shape until completely burned (when you see this you will understand what I mean), plus the smoke coming out of the chimney will not smell.
Another no-no with respect to your stove is burning wood slowly with minimal air supply. In addition to poor secondary burn, this approach will also lead to nasty black tar deposits in your flue, which increases the likelihood of a chimney fire, and deposits on the stove glass.
Stewart's two simple rules
So, remember these two simple rules:
1) Burn hot, and
2) Secondary air supply to dominate
Follow these rules and you will get much more heat, burn less wood and radically reduce emissions. Then you can enjoy burning your wood in the comfort of knowing you really are doing the right thing.
Image credit: SuperHomes
If you have a question about anything in the above blog, please ask it in the comments section below.
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