What Does The Efficiency Rating On Your Furnace Really Mean?

What’s the most important item you should look at when selecting a new furnace?

The efficiency rating will help you decide how much it’s going to cost to heat your home each month. The higher the rating, the greater the amount of heat that is produced compared to the energy used to produce it.

When you look at new furnaces, you will find they rate efficiency by the Annual Fuel Utilization Efficiency rating – or AFUE. This tells you how much heat the furnace produces compared to the amount of energy it needs to produce the heat. If a furnace is rated 80 percent AFUE, it means 20 percent of the energy is lost during the heating processed, and only 80 percent of the energy actually turns into heat.

It’s also important to understand that this rating takes into account the energy process in the furnace only. It doesn’t include potential heat loss throughout the heating system, including your duct work. If your ventilation system is old and in need of repair, efficiency can continue to drop off rapidly.

If you have an old system, it might not be marked with an AFUE rating. You can identify and compare efficiencies with newer models based on the heating equipment features.

Old low efficiency models have:

• Pilot light
• Natural drafts to create air flow
• Heavy heat exchanger
• 56 to 70 percent AFUE

Mid efficiency systems have:

• No pilot light
• Exhaust fan controls air flow and gas more efficiently
• Compact size
• Smaller diameter flue pipe
• 80 to 83 percent AFUE

High efficiency systems have:

• Condensing units for flue gases
• Sealed combustion
• 90 to 98.5 percent AFUE

The biggest advantage of replacing an old, less efficient furnace is the energy savings. Upgrading to a newer furnace can often cut your utility bills by as much as 50 percent. It also decreases your carbon footprint, reducing the amount of carbon dioxide emissions your system produces every year.

If you’re ready to increase efficiency in your home, the best place to start is with an energy audit. We can evaluate your current system, give you tips to make your home as energy efficient as possible, and give you options for which furnace is best for your home.