1797 Park Drive, Traverse City, MI 49686
Phone: 866-BOB-HEAT

Boiler Efficiency: Discover AFUE Ratings

If your home or business has a boiler, you should know about AFUE ratings. AFUE stands for annual fuel utilization efficiency, and it’s similar to other rating systems for air conditioners and other appliances. Knowing what it means can save you money by helping you heat your home more efficiently.

What The Rating Means

AFUE refers to the amount of heat a boiler or furnace puts into your home compared to the amount of fuel it uses. So if a unit has an AFUE rating of 90 percent, that means 90 percent of the fuel is converted into heat for your home and 10 percent escapes through vents, chimneys and elsewhere. The higher the rating, the more efficient the unit.An appliance must have an AFUE rating of 85 percent before it can earn the Energy Star label.

Be aware that the AFUE rating doesn’t measure the rate of heat loss through your heating ducts and pipes. The  Department of Energy estimates this heat loss could be as much as 35 percent. So a boiler with a higher AFUE rating can help offset any heat loss through your ductwork.

Choosing The Right System

All boilers have advantages and disadvantages that affect their AFUE rating:

  • All-electric system: All-electric units have ratings of 95 percent for units located outside to 100 percent for indoor units.
  • Fossil-fueled system: The minimum rating for a fossil-fueled unit is 80 percent.
  • Gas-fueled system: The minimum rating for a gas-fueled steam boiler is 75 percent.

There are also differences between condensing units and non-condensing units. A condensing unit uses heat from condensed water vapor to heat a home. These units often have much higher AFUE ratings, making them more efficient and a good choice for colder climates where heating costs run much higher.

If you’d like to know more about AFUE ratings and energy-efficient boilers, contact Team Bob’s Heating Cooling Plumbing.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about AFUE ratings and other HVAC topics, download our free Home Comfort Resource guide.

Team Bob’s services Traverse City, Michigan and the surrounding areas. Visit our website to see our special offers and get started today!      


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Thank you for considering Team Bob’s for your heating, cooling, and plumbing needs! If you need immediate assistance, please call our 24/7 emergency hotline at 866-BOB-HEAT. Otherwise, please select a date and time below to request an appointment.

Please note: Your requested appointment date and time is not guaranteed. A member from our team will contact you by the following business day to confirm your appointment date and time.