efficient wood stove?
Can a wood stove be efficient? Is there a way to increase the
efficiency of a wood stove?
Not everything in our house is high-tech. For those cold winter
days that are neither sunny nor windy we have to have a low-tech
method to warm up the house.
Just because a wood stove is considered low-tech it doesn't mean
that it should be inefficient. We started with a Morsø
stove that was 71% efficient (test according to Autralian Standard
4012) and improved its efficiency by installing a non-standard
flue and a cold air intake.
The long and non-vertical stainless steel flue helps to cool down
the hot fumes before they fly away, and hence helps to retain
more heat from the burned fuel in the house interior.
This is especially noticeable when we start the fire. While the
firebox is still cool to touch, the flue radiates plenty of heat.
Some people argue that there are no benefits for using outside
cool air intake for wood stoves and that the best source of combustion
air for wood stove is the room in which people live and try to
If taking combustion air from where people are present was really
a good idea, why combustion air for car engines is not drawn from
inside car cabins?
An outside cold air intake in the ash compartment of the Morso
2110 wood stove is installed in a way that we can compare behavior
of my stove with different combustion
just by opening and closing valves without touching the fuel or
altering the fire under various atmospheric and other conditions.
From our experience the cold air intake is amazingly better that
a room air intake. There is no comparison. I actually see no reason
to use an interior air intake for our wood stove...
Please read the pdf
article describing our wood stove cold-air-intake in detail.
We estimate that with the long non-vertical flue and cold-air
intake the efficiency of our wood stove approaches 80%. This efficiency
is nearly 4 times higher than efficiency of the electricity production
from fossil fuels such as brown coal !!!