AFUE Ratings: What They Mean When It Comes to Furnace Efficiency

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Most homes in the U.S. are either heated with boilers or furnaces. Although they perform essentially the same function, they utilize different methods to distribute heat throughout your home.

Furnaces use air, while boilers use water.  When determining which appliance is the most efficient, refer to the equipment’s AFUE rating, which reflects its efficiency.

The annual fuel utilization efficiency, or AFUE, rating measures the heat generated by the appliance versus the amount of fossil fuel that’s used to generate that heat, and all over the span of an average year. This means an appliance that has an AFUE rating of 93 uses 93 percent of the fuel for heat, while 7 percent is wasted. Unfortunately, this efficiency rating doesn’t take into account the amount of energy that can be lost due to faulty piping or ductwork, which can be as high as 35 percent.

Appliances with a high AFUE rating can cut utility bills dramatically. In days past, the highest efficiency heaters and furnaces were approximately 70 percent efficient. Nowadays, though, some appliances have ratings as high as 98.5 percent. To make it easier for consumers to determine the efficiency of their new heating units, the Federal Trade Commission (FTC) has ordered that all new models must have their AFUE rating displayed.

If you own an old heater or furnace that is still in good working condition, you may be able to get it retrofitted in order to improve its efficiency. However, if you’re planning this as a short-term solution, it’s a better investment to bite the bullet and purchase the newer model now, particularly with federal tax credits available through the end of 2013. Additionally, opt for equipment with the Energy Star label to ensure efficiency.

Before you make any purchasing or retrofitting decisions, perform renovations to your home to improve its energy efficiency. Once completed, hire an HVAC professional to properly size your furnace replacement. The sizing information will go a long way in determining the smallest and most efficient unit for your home.

For more information about AFUE ratings and other HVAC concerns, contact the pros at Apollo Home Heating, Cooling and Plumbing. We’re proud to serve homeowners throughout the greater Cincinnati area.

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- Randy B.
"We scheduled an estimate AND a tune-up. We knew something was wrong with our furnace, but hoped we could make it through the rest of the season. Upon telling Bill what our furnace was doing, he warned us immediately what the possible outcome was going to be; a cracked heat exchanger. He watched the flames roll backward, tested carbon monoxide levels, which were so high they meter’s last reading was 5,600 before saying “high”. He immediately shut it down, tagged it, and explained that with levels that high and children in our home he wanted off right away. He continued his inspection and showed us via a camera that not only was it cracked in multiple places, but had holes all over it. He gave us a few options for repairing it; his knowledge as well as genuine concern was beneficial and refreshing. Luckily we also scheduled an estimator, Micah, to come too and we were able to get costs between repairing and replacing (with several options). We decided to replace with a much higher efficiency furnace and one sized properly to our home. Hands down, not only did they both provide us great service and knowledge, but without sounding dramatic, they may have saved our lives. This was our first time calling Apollo, but it won’t be our last."
- Sarah B.
"Apollo is an excellent company. I always receive great service. Alex A. was professional and friendly. He kept me informed during the process of checking my furnace and heat pump to make sure they were working properly. The company makes sure you are notified who is coming and when they are on the way. All my interactions with the company have been wonderful."
- Beverly S.



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