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Boilers Key Product Criteria

Equipment Specification
Boilers Rating of 85% AFUE* or greater (About 6% more efficient than the minimum federal standards.)

ENERGY STAR partner agrees to sell one or more specific models of boilers that meet or exceed 85 percent AFUE energy efficiency ratings. Residential Boiler: A self contained fuel burning appliance of less than 300,000 Btuh energy input, for supplying low pressure steam or hot water for space heating applications. A heating unit that meets this definition and also provides hot water for domestic or other use is considered a boiler. Combination Space-Heating and Water Heating Appliance: Appliance that provides both space conditioning (boiler) and hot water heating with one appliance or energy source. The combination appliance circulates hot water from the water heater through a heat exchanger in the air handler. A blower will move the heated air through a standard duct system. In the summer, an air conditioner is connected to the exchanger and the system functions similarly, with cool air being pushed through the ductwork.

The Annual Fuel Utilization Efficiency (AFUE) measures the amount of fuel converted to space heat in proportion to the amount of fuel entering the boiler. This is commonly expressed as a percentage. The efficiency of a boiler shall be measured using AFUE. Test procedures have been developed to test AFUE by the Department of Energy (DOE). These procedures are specified in 10 CFR part 430.
The Combined Appliance Annual Fuel Utilization Efficiency (“CAafue”) is the effective efficiency of the combined appliance in performing the function of space heating. When the primary heating source of the combined appliance is a residential boiler, the CAafue is the same as the AFUE of the boiler as determined by DOE test procedures specified in 10 CFR 430.