What Furnace Efficiency Rating Means in Laymans Terms

What Does Furnace Efficiency Rating Mean in Layman’s Terms?

When it comes to choosing a new furnace, energy efficiency is a prime consideration for most homeowners. To determine the efficiency of a furnace, it is important to understand a little industry terminology.

Annual Fuel Efficiency Utilization Rating

Regardless of the fuel source, every furnace manufactured is evaluated and assigned an annual fuel efficiency utilization rating, also known as an AFEU rating. An independent organization within the HVAC industry determines this rating by calculating how much of the available fuel is actually used to heat your home versus how much is lost through venting. For example, a furnace with an AFEU of 90 percent will produce 90 BTUs of heat for every 100 BTUs of fuel input. The rating takes into consideration the normal cycling of the unit as well as energy losses that may occur as a result of load changes. In actual use, the AFEU can also be affected by adjustments that the homeowner makes to the unit and weather changes.

A Layman’s Explanation

A simpler explanation is to think of the AFEU in terms of money. For example, if you have a furnace that is 95 percent efficient, 95 cents out of every heating dollar is actually used to heat your home. The remainder is vented out through your flue. If your furnace is only 85 percent efficient, then you are losing 15 cents out of every heating dollar to venting. This means that even a relatively small change in the efficiency rating of your furnace can have a significant impact on your wallet and home comfort.

Department of Energy AFEU Standards

In 2015, the United States Department of Energy increased the minimum AFEU standards for new furnaces. All new furnaces sold in the United States must meet the following standards.

  • Gas boilers must have a minimum AFEU of 84 percent.
  • Weatherized gas furnaces and oil-fired boilers are required to have a minimum AFEU of 83 percent.
  • Oil-fired furnaces have a minimum standard of 82 percent.
  • Mobile home gas furnaces and non-weatherized gas furnaces must have an efficiency rating of at least 80 percent.

Furnaces manufactured before 1992 may have an efficiency rating as low as 70 percent.

Choosing an Energy Efficient Furnace

Furnaces that carry the Energy Star logo offer the highest level of efficiency. The following are features that you should look for to make sure your furnace is as efficient as possible.

  • Choosing a unit with an electric ignition can improve efficiency by as much as 6 percent by eliminating the need for a continuously burning pilot light.
  • A furnace equipped with a secondary heat exchanger allows you to capture the hot vent gases that normally escape through the flue to preheat the household air.
  • Furnaces can lose heat through the walls of the furnace cabinet. Energy efficient models will have a blanket of insulation lining the cabinet to prevent heat loss.
  • An induced-draft blower will ensure proper venting and keep heated gases moving through the heat exchanger at a constant rate; however, it will shut off when the burner cycles off to keep the heated air in the system.
  • You can reduce the amount of heat escaping the furnace by using a smaller diameter flue pipe.
  • A furnace with sealed combustion chambers will allow less heat to escape through the chimney.

The Benefits of a High-efficiency Furnace

It is true that you will probably pay more for a high-efficiency furnace; however, you will most likely recoup the cost in the long-run in the form of lower operating costs. Since many of today’s home buyers are concerned about energy efficiency, upgrading your furnace may even enhance the resale value of your home. In 2012, the American Council for an Energy-Efficient Economy issued a report detailing cost savings in relation to the AFEU rating of a home’s heating system. The report showed that if you currently have a system that is only 50 percent efficient that you could save up to $47 out of every $100 spent on heating by upgrading to a furnace with an AFEU of 95 percent.

Furnace and Boiler Replacement in Denver, CO

Swan Plumbing, Heating & Air is proud to be Denver’s home comfort experts. If you are looking to replace your old, inefficient furnace or boiler, you can rely on our trusted professionals to make the process hassle-free. You will receive our price up front and in writing with no high-pressure sales tactics. We also bill by the project and not by the hour, so there will be no unpleasant surprises. We realize that a new heating system is a major financial investment, and we are happy to offer financing plans to suit almost every budget and situation. You can rest assured that the job will be completed correctly, and we do not consider the job finished until you are 100 percent satisfied. We carry furnaces from all of the top manufacturers, and our industry-certified technicians can help you determine which brand and model will be best for your home and family.

Contact us today for more information or to schedule an in-home evaluation. We look forward to the opportunity to serve you.

Comments for this post are closed.