What is a High Efficiency Furnace?

In short, a high efficiency furnace uses less energy to operate than a standard furnace, as a result it generally has a higher energy efficiency rating. There are tons of furnaces out there that claim to be high efficiency or to lower your energy bills. So, it is important, as a consumer, to be aware of how these attributes are determined and to be prepared to discern the efficiency level of a furnace without a salesman to lead you.

High AFUE — High Efficiency!

AFUE: This stands for the Annual Fuel Utilization Efficiency score. It measures the thermal efficiency of combustion equipment like furnaces, boilers, and water heaters. The AFUE does not measure the peak efficiency of the appliance, but is rather a composite score of the average efficiency of the unit throughout a full year. This gives a clearer picture of how efficient the furnace will actually be throughout the year, instead of the efficiency it could achieve.

The AFUE score is represented as a percentage. This reflects a direct ratio of Btu’s used as fuel to Btu’s of useful heat expelled from the furnace. So, if you have an AFUE score of 97% (a very high score indeed!), for every 100 Btu’s of fuel used, 97 Btu’s will be pumped into the home.

So Where is the Bar?

A great way to gauge whether or not something is high efficiency is to look for the Energy Star insignia on the product. Energy Star is a 3rd party organization which certifies and honors products which are exceptionally energy efficient. So, if it’s Energy Star, it’s energy efficient. This is a great place to start when choosing a furnace, because in Illinois, in order to qualify for Energy Star, the furnace must have an AFUE rating of 95% or higher!


A Changing Industry

The HVAC industry is always developing more and more efficient designs for their furnaces. So, similar to the technology industry, as a rule of thumb if your furnace is not brand new, there is a more advanced model on the line. However, instead of replacing a new furnace immediately, this means that any furnace you purchase will be more efficient that one from 20 years ago. Browse the Four Seasons furnace products page to view our incredible Lennox products, or if you would like to check out our most efficient model, follow this link to the SLP 98V!