See the enclosed letter from the EPA to Central Boiler written a few weeks ago. Keep in mind that OWB manufactures knew that the efficiency rating shown on hang-tags attached to their units, and published in their marketing materials, were flawed as early as 2010 when the EPA pulled the efficiency data from its Burnwise website. Also relevant is the fact that many states promulgated its laws based on these flawed efficiencies. For example, the EClassic 2300 showed 86% efficiency on its hang-tag and that's what was listed on the Burnwise website. A study sponsored by the EPA showed the EClassic 2300 (three stage HH) as having only 30% thermal efficiency under real-world use. This is one of the reasons the efficiencies were pulled in late 2010. The EPA told the manufacturers about the flawed efficiencies at the time they were pulled from Burnwise but the manufacturers elected not to remove them from the hang-tags or their marketing materials. In essence, they continued to misrepresent the boilers to consumers until the recent EPA letters were sent. The only reason the EPA sent the letters out last month is because they knew that a number of law firms found out about the flawed efficiencies and elected to do damage control. In other words, push blame on the manufacturers by proving that the manufactures knew about the flawed efficiencies yet decided not to remove them ( remember it's a volunteer program) From a consumers perspective, if a person pays $200 dollars for a full cord of wood and the OWB burns an average of 13 full cords of wood per heating season, the consumer expects only 14% waste (100 - 86%) or $364 dollars per heating season based on a 86% thermal efficiency. Based on the Gullett’s study a person who purchased a EClassic 2300 actually loses $1820 dollars per heating season because the actual efficiency is only 30%. 70% (waste based on 30 percent efficiency) x 200 (per cord) = $140 (waste per cord) x 13 cords of wood = $1820 Additionally, when a consumer shops for a heating appliance many base their decision to purchase on the efficiency of the device. In essence, they compare to other appliances such as gas, oil and electricity before making the purchase. As you can see from the aforementioned example consumers' are being duped and neighbors are suffering the consequences - efficiency has a direct coloration to smoke and pollution. The higher the efficiency the hotter the fire burns and hence less smoke and PM 2.5. Lastly, after Method 28 OWHH was found flawed , also as a result of the efficiency issue, NESCAUM and NYSERDA strongly questioned the raw data obtained from Method 28 OWHH on all models tested, to include the data which determined the amount of Particulate Matter measured for each test. The EPA baulked because it would require them to force retesting for 23 models at 20 thousand dollars per test. This would obviously prompt lawsuits against them from manufacturers so they massaged the data to salvage the PM results. Bottom-line is the PM results are suspect too. For over three years now consumers have been intentionally mislead into purchasing Phase II OWBs based on deliberate false marketing schemes costing consumers thousands of dollars. Both the EPA and manufacturers are complicit.