![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Understanding the Orange Tag
This orange tag identifies outdoor wood-fired hydronic heaters that meet EPA’s Phase I emissions levels for the voluntary program. Models that carry this tag have been tested by an EPA-accredited laboratory and are cleaner than other models.
The following are definitions for specific parts of the hang tag to help you as the consumer, better understand how your model was rated. To view the definitions, click on or place your mouse on the red number directly on the hang tag graphic.
Seasonal vs. Year-round burning - an OWHH is rated for either seasonal or year-round burning. A "year-round" unit has been tested and meets the criteria for potential usage 12 months of the year. A "seasonal" rating designation is for units that are specified for use only during winter months (approximately October through April).
"This Model" Designation - shows the pollution emission level (measured in lbs/million BTU heat input) for this particular OWHH model. This number resulted from the emissions test (EPA Method 28 OWHH) used to compare the OWHH device with the EPA qualifying emissions level.
0.6 EPA Phase I Emissions Level - the OWHH must meet this level to qualify for the EPA Phase 1 voluntary program. This level is calculated in lbs/million BTU input (i.e., wood fuel burned).
Phase I - is the initial step of EPA's phased program to provide better choices to consumers of OWHH models that are cleaner and more efficient than current models.
8-Hour Heat Output Rating - describes how much heat this model can provide in eight hours (measured in BTU/hour).
BTU - is short for British Thermal Unit. A BTU is a measure of an amount of heat. Specifically, a BTU is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit.
Grams/hour - shows the amount of pollution (measured in grams) per unit of time (measured in hours). This number is essential for estimating air quality and health impacts. For comparison, most current OWHH are estimated to emit 100-300 g/hr whereas most current EPA-certified woodstoves emit less than 4 g/hr and some emit less than 2 g/hr.
XX lbs/ Million BTU Heat Input - shows the amount of particle pollution per amount of wood burned. For comparison, most current OWHH are estimated to emit 1.5-5.0 lbs/million BTU heat input whereas most current EPA-certified woodstoves emit 0.8-1.5 lbs/million BTU heat input.
Grams/Hour/10,000 BTU Heat Output - shows the particle pollution per hour per every 10,000 BTU of heat output. This calculation takes into consideration varying sizes of OWHH units. In general, larger models typically emit more pollution but they also provide more heat output if the efficiency is the same. Although EPA's primary interest is reducing emissions to protect public health, EPA is also encouraging manufacturers to increase the efficiency of their OWHH which typically reduce emissions for a given heat output. For comparison, many current OWHH are estimated to have combustion efficiencies of only 30-40 percent whereas most current EPA-certified woodstoves and wood pellet stoves have efficiencies of 67-80 percent.
Accredited Independent Laboratory - EPA has provided official authorization for certain OWHH testing labs in the United States. An important criterion is that these labs are independent of the manufacturers. Also, this accreditation is determined by reviewing a lab's performance, their capabilities for completing specific types of testing, and accurately and fully compiling results data.
EPA Method 28 OWHH - is the EPA test method for measuring emissions and heat output for OWHH. This is a standard test method which all manufacturers must follow to participate in this voluntary rating initiative.
Emissions Level - designated by EPA as a maximum of 0.60 lbs of particle pollution per million BTU heat input. EPA established this number with input from various stakeholder groups such as industry manufacturers, EPA-accredited woodstove testing laboratories, state air quality agencies, and the Northeast States for Coordinated Air Use Management (NESCAUM).