rdust had this to say in a previous thread...
BK numbers are also average heat output numbers, not the max numbers under ideal conditions. Under ideal conditions they say 90K is achievable.
From page 15 of their manual.
The Facts On BTU’s:
There are only two rating methods that mean something to you the consumer. The first is the Btu output that is achieved
during EPA testing. This testing is quite complicated and costly milled woods are burned. This is a standard for all manufacturer
testing and is not intended to provide consumers with a model for how a stove will burn in their home. The second
method that counts is what Blaze King refers to as the “Real World†method. These btu’s are achieved during in
house testing using the same thing a consumer burns, split, dry, cordwood. In our tests, we use fir. The “Real Worldâ€
btu’s listed are what the average consumer can expect to achieve, with slight variations depending upon geographical
location, type of wood, elevation and the amount of fuel added. Higher btu’s are possible. If you were to stand in front of
your stove and frequently add fuel, burn the unit on high and have optimal conditions, the PEJ1006 could produce as
high as 87,500 btu’s and the KEJ1107 could exceed 90,000 btu’s! However, maximum btu’s would only be achievable at
certain “peak†times during the burn. Blaze King does not wish to mislead you so we give you all the facts.