I became curious about relative efficiency of pellet stoves so I did some digging. It turns out that the EPA does publish a document that has efficiency information on many stoves. http://www.epa.gov/oecaerth/resources/publications/monitoring/caa/woodstoves/certifiedwood.pdf For some peculiar reason they lump pellet stoves in with wood stoves and even more peculiar is that there are significant omissions from the list. An example of their omission: My Mt Vernon manual states that it is certified and gives a test file number in the owners manual, but is not listed in the EPA document. Unfortunately the document only gives EPA assigned efficiencies for pellet stoves, there is no actual test data. This makes the document next to useless. Our government at work! Is there a document out there that does a real job of collecting this data?