follow up 9 years later https://www.hearth.com/talk/threads/anyone-with-a-p68-getting-anything-close-to-68-000-btus-out.121656/#post-1629319

[J1809]

Finally found the answer. 68k btu is the 'theoretic' BTU output based on ideal pellet BTU rating and INITIAL AUGER FEED SPEED. Yup, you read that right.

 

[johneh]

Well goes to show that if you can't blind them with brilliance
Baffal them with BS

 

[bogieb]

Not sure why this was a mystery. I can find threads back to 2009 (here and other places) that the indicate it is the feed rate times btu of pellets, and then account for efficiency. Pretty much the same as for a wood stove. The mfg can't possibly know (or care) if you are using super softies, cold burning thermaglos, super hot java pellets, or even mixing in corn. So really, that btu thing is just a guide anyway.

EPA rated stoves, to my understanding, have to go thru actual testing. The P68 is not EPA rated, so of course 68k would be a theoretical max. I am pretty sure that if the feed rate is 10, that stove would be feeding darn fast.

 

[ABusWrench]

Not sure why this was a mystery. I can find threads back to 2009 (here and other places) that the indicate it is the feed rate times btu of pellets, and then account for efficiency. Pretty much the same as for a wood stove. The mfg can't possibly know (or care) if you are using super softies, cold burning thermaglos, super hot java pellets, or even mixing in corn. So really, that btu thing is just a guide anyway.

EPA rated stoves, to my understanding, have to go thru actual testing. The P68 is not EPA rated, so of course 68k would be a theoretical max. I am pretty sure that if the feed rate is 10, that stove would be feeding darn fast.

It's rated @ input btu's, not output. It is also EPA certified.

 

[bogieb]

It's rated @ input btu's, not output. It is also EPA certified.

Well, you are right. I didn't check to see if they are currently EPA rated. Not that it really matters since that rating is for output of exhaust particulates, and has nothing to do with output of heat, so I'm not even sure why I put that statement in my post. Some days I am just not thinking as clearly as I should be.

 

[mtnbiker727]

All I can say is my P68 gets HOT and provides much nicer heat at a much lower price than the electric baseboards that are in this house.