Home Furnace Buying Guide

What Furnace Is Most Efficient?

Coming to the decision to buy a new furnace is a big one, your investment will last you many years to come and will also have to work hard to provide your home with the comfort you are demanding from it. Operating efficiency should not be the only thing that is considered; other factors should go into your decision when buying a furnace. Some of the most common questions and demands for furnace include the following:

  • Operation Efficiency – Will it work up to or past my expectation for a heating unit?
  • Energy Efficiency – If it works up to my expectation will it cost me a lot of money to use?
  • Noise – Will my furnace be loud to the point that it bothers me?

If you are preparing to buy a new furnace for you, home it usually means you did not have a heating system before or that your current heating system has died. If your past heating system has been damaged beyond repair, it could have been caused by damaged machinery, or wear and tear over time. A lot of furnaces are meant to last more than 20 years, but with technology advancing as fast as it is and more efficient models coming out, you might find a more efficient furnace that would justify a replacement every 10-15 years.

Newer furnaces come with the technology to offer operational efficiency, energy efficiency, and reduced noise.

  • Heating and cooling account for 56% of a U.S home’s energy costs
  • 30% of which is from heating
  • Getting as much heat at the lowest cost should be a priority for any long-term home investment

What is considered a high-efficiency furnace?

Defining Efficiency: Getting the most amount of heat for the lowest amount of energy. This is what defines efficiency for your heating and cooling equipment.

Do not be mislead by advertising or company description of their products saying their furnaces are high efficiency. There is a clear explanation of what would be considered a high-efficiency heating or cooling system.

The Department of Energy (DOE) definition of high efficiency:

  • High-Efficiency Furnaces: Energy Efficiency Rating above 90
  • Mid-Level Efficiency Furnaces: Energy Efficiency Ratings between 80-83
  • Minimum requirements will vary but will be tighter as the years go by

Old, low-efficiency furnaces with the natural draft flue gas, continuous pilot light, thick walled heat exchanger may provide efficiencies ranging from 56% to 70%. New, high-efficiency furnaces with condensing heat exchanger, fan-assisted exhaust, and electronic pilot light may provide efficiencies ranging from 93% – 99%.

Annual Fuel Utilization Efficiency (AFUE)

A furnace’s efficiency is measured by annual fuel utilization efficiency (AFUE). AFUE is a measure of how efficient the appliance is in converting the energy in its fuel to heat over the course of a typical year. Specifically, AFUE is the ratio of annual heat output of the furnace or boiler compared to the total annual fossil fuel energy consumed by a furnace or boiler.

AFUE ratings run from the 80 percent minimum to 98.5 percent. The meaning of this percentage is very simple: This is the ratio of the furnace’s annual fossil fuel that is converted into usable heat. In other words, the highest-performing model converts 98.5 percent of its fuel into heat.

For Example: 

  • An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the flue and elsewhere.

This does not account for heat loss that occurs from the duct system.

Where Can I locate my Furnace’s Energy Efficiency Rating?

Furnace efficiency ratings can be found on a yellow label by “Energy Guide” that is stickered onto the furnace. This label is required to display according to the Federal Trade Commission. These guides are great because they tell you a lot about the furnace before you buy it. The energy efficiency label will allow you to compare which furnace will be more cost effective and where the furnace can be installed. Consider the energy rating label as an indicator of how many cents per dollar goes into actually heating your home.

Pros and Cons of an Electric Furnace

We talked in the previous portion about energy efficiency and how the difference from 100 on the energy efficiency label gets lost in a gas furnace’s flue.

  • Pro: Electric furnaces do not have this problem, and they do not lose heat from the flue because it does not have one. Electricity furnaces have energy efficiencies between 95-100%.
  • Con: Electric furnaces are expensive, so expensive that it rarely makes sense to own one.

If you were to choose an electric heat source for your home, it would be better to consider a heat pump. Heat pumps perform both heating and cooling that is the added advantage of going this route.

Choosing the Right Furnace For Your Home

Resources to start:

  • Energy Star has a list of their most efficient furnaces
  • A look into the different Brands available
    • Bryant
    • Carrier
    • Frigidaire
    • Heil
    • Lennox
    • Maytag
    • Temptstar
    • York
  • Adams Manufacturing produces a condensed oil fired furnace with an efficiency rating of 99

How One Hour Heating and Air Conditioning Can Help

Factors to consider when getting a new furnace or replacing your old one can be many, that is why calling for professional help is always a good idea. If you are unfamiliar with heating and cooling systems, you will need someone to do some of the following for you to make sure your home’s furnace runs efficiently throughout its entire life cycle.

  • Inspecting for duct leakage (remember heat loss is an important factor of energy efficiency)
  • Proper sizing of the furnace
  • Room x room heat loss calculations
  • Modulating output – helps lower burner and fan rates

Call One Hour Heating & Air Conditioning® of Elk Grove at (847) 744-9447 today for advice on properly planning your new furnace installation and replacement.