Furnace efficiency begins with the AFUE rating determined at the factory. Short for Annual Fuel Utilization Efficiency, AFUE is a percentage that expresses the amount of fuel consumed that actually produces heat versus the percentage lost during combustion and venting.
Mandated by federal regulations, today the AFUE standard efficiency rating for furnaces is 80%. More expensive high-efficiency furnaces that recover lost heat, however, come with an AFUE as high as 95%.
AFUE is simply the starting point for determining furnace efficiency. Additional factors also play a role in the efficiency you actually receive once the unit is installed and in operation.
A typical gas-fired furnace has a life expectancy of 15 to 20 years. If an existing older unit is installed in your house, efficiency standards when that furnace was manufactured may have been significantly lower than today, while energy costs have increased. Upgrading to a new unit that meets current AFUE standards could result in lower operating costs plus better heating performance from day one of installation.
Upgrading a furnace should always include a formal heating load calculation. Performed by a qualified HVAC technician using industry-standard software, data about the unique thermal characteristics of the house is crunched to generate the precise furnace BTU capacity for optimum operating efficiency. If rough guesstimates or a one-size-fits-all approach are utilized—instead of an accurate load calculation—an over-sized or under-sized furnace may be installed, resulting in excessive energy consumption and poor heating performance.
To keep a furnace running at its original AFUE energy efficiency rating, annual preventive maintenance is critical. This procedure performed by a qualified HVAC technician supports maximum system efficiency, reliable heating performance and safe operation. It’s also required by the warranty terms of most major manufacturers.
Furnace efficiency is also affected by external factors such as condition of the home’s ductwork as well as the amount and quality of insulation in the house.
For qualified sales and service that support maximum furnace efficiency, contact the pros at Powers Heating & Air.
Our goal is to help educate our customers in Peachtree City, Georgia and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, download our free Home Comfort Guide or call us at 770-487-2040.
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