Blaze King manufacturers the top 2 most efficient wood stoves in North America. The King being #1 at 88% Optimum Efficiency (LHV) and 82% Real World Tested Performance (HHV), as listed by the EPA. #2 is the Princess at 88% Optimum Efficiency (LHV) and an 81% Real World Tested Performance (HHV) as listed by the EPA. We also build 5 of the top 8 most efficient wood stoves listed on the US EPA (Environmental Protection Agency) web site. The true efficiency for a wood stove is the measured efficiency number published by the US EPA on its web site (HHV). When comparing efficiencies of different brands you should always compare the EPA measured efficiency. This number is a true reading of how your stove performs in the real world. Follow this link to the EPA web site for confirmation. Here you will see most other wood stoves listed at 63% while the Blaze King stoves are listed as high as 82%. Our efficiencies keep the heat in your home and saves you up to 33% on your wood use.