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Efficiency Measurements and Types of Fires
There are different ways of expressing efciency and to correctly compare values.
Combustion Efficiency - Input Based
The amount of fuel that is completely burned compared to the total amount available for combustion expressed
as a percentage.
For example:
An open bonre; 100 pounds of wood burns and produces three pounds of ash, which equals 97
percent combustion efciency. Good combustion efciency but poor heating efciency. No heat got into
the house.
Heating Efficiency - Output Based
The percentage of the heat produced that was actually absorbed into the water and transferred into the house
from the Heatmor
TM
.
Net Efficiency
This is the product of the combustion and heating efciencies. Ninety percent combustion efciency times 60
percent heating efciency results in a 54 percent net efciency.
Loading Of The Furnace
Loading the furnace relative to the heat load will result in more efcient performance. More nearly matching
your fuel load to the current temperature conditions for an 8 to 12 hour burn will result in longer burn cycles,
higher overall burn temperatures and more efcient performance. Your furnace has been rated for an 8 hour
burn cycle. Burning wood with less than 30% moisture content will also result in better efciency.