High Efficiency Furnace

11 Oct. 17

Understanding Furnace & Boiler Efficiency Ratings

Often times you’ll hear us discuss the importance of energy efficiency when referring to new furnaces or boilers. But how can energy efficient HVAC Systems help you save money?

Furnace and boiler efficiency is measured in AFUE or Annual Fuel Utilization Efficiency. This is a percentage that represents the amount of natural gas that is actually converted into heat for your home.

For instance, an 80% AFUE furnace uses 80% of its gas to create heat, and the other 20% is lost during the combustion process. Therefore, the higher the percentage, the less gas you will use, and the lower your energy bills will be. There are different efficiency ranges, and it is important to understand the benefits and losses associated with owning a unit that falls within one of these ranges.

The Energy Efficiency Spectrum

  • 65% AFUE or Lower: The general rule of thumb when determining the energy efficiency of your current heating system is: the older the unit the lower the rating. Most furnaces and boilers that are fifteen years old or older are at best 65% efficient with the gas that they consume. This is extremely wasteful, and operating a system that is this inefficient is a waste of your hard earned money.
  • 78% AFUE- 81% AFUE: This range of efficiency is considered a “mid-range” energy efficiency rating. This is the current requirement set by our government for the minimum efficiency rating required for new units. An upgrade to this level of efficiency will give you noticeable savings on your monthly gas bills, but when you live in cold climate, the higher the efficiency, the better the savings.
  • 90% AFUE-97% AFUE: Furnaces and boilers that are rated this high waste very little gas and will save you big bucks on your energy bills. They also often come with several other features that improve home comfort and offer user friendly operation to the homeowner. Lennox Home Comfort Systems are at the forefront of HVAC technology, and when you purchase your new Lennox system from us, you can rest assured that you are not only receiving a top quality product but also a first class installation.

Depending on the age of your system, you may already have an idea of how inefficient it truly is. If you are interested in learning more about the energy efficient systems we offer or if you need help determining the efficiency of your current furnace or boiler, fill out our online form to schedule your free in-home estimate.