Note: This blog speaks to gas furnaces. If you have an oil or electric furnace, these efficiency levels will not apply to your furnace.
If you’re considering buying a new furnace, you’re probably wondering if you should go with a mid-efficiency unit (80% AFUE) or a high-efficiency unit (95% AFUE).
Here’s our answer: Since we live in a cold climate here in Pittsburgh, we usually recommend going with a high-efficiency furnace (especially if you use utility rebates and/tax incentives).
A high-efficiency furnace can save you money in the long run. That said, your actual long-term savings depends on several complicated factors and requires a professional’s help to calculate.
In this blog, we’ll break down:
- Key differences between 80% AFUE and 95% AFUE
- How to determine if a high-efficiency furnace is a cost-effective solution for you
Want to have an expert figure out which efficiency furnace is best for your Pittsburgh home? We can help! One of our techs can help determine which furnace is best for your home as well as install a new furnace.
Key differences between 80% AFUE and 95% AFUE
The higher the AFUE percentage, the more efficient a furnace is at converting gas into heating energy.
That means a 95% AFUE furnace will cost less to run than an 80% AFUE furnace.
But besides the level of efficiency, another key difference between the 80% AFUE and 95% AFUE furnaces is that they operate a little differently.
Atmospheric combustion vs. sealed combustion
An 80% AFUE furnace uses atmospheric combustion to create energy. Essentially, these furnaces use air from inside your home and mix it with natural gas from the burner to create combustion.
A 95% AFUE furnace uses sealed combustion. This type of furnace has a combustion chamber that’s sealed off from the rest of the house and sucks in air from outside your home to create combustion.
Sealed combustion furnaces are usually a better option because they offer:
- Increased comfort: When an atmospheric furnace pulls air from inside your home to use for combustion, it creates a vacuum that makes cold outdoor air rush into your home. This means your indoor air will be drier and colder. However, since a sealed combustion furnace doesn’t remove heated air from your home to use for the combustion process, it eliminates this vacuum, which makes it easier to heat your home and have proper indoor humidity levels.
- Improved safety: Sealed furnaces reduce backdrafts and combustion vapor leaks, which makes them safer than atmospheric furnaces.
Note: Since sealed combustion furnaces require a special pathway for outside combustion air to enter the unit, they typically cost more to install than an atmospheric combustion furnace.
How to determine if a high-efficiency furnace is worth it for you
Now that you have all of this information, it’s time to determine if a high-efficiency furnace is worth it for you.
To help you quickly get a rough estimate lifetime savings, you can use an energy calculator like the one offered by Lennox.
But the most accurate way to determine which furnace is best for you is to have a professional provide an AFUE recommendation.
A professional can show you the savings you’ll get with a higher AFUE furnace over the lifetime of the unit so you can determine whether the higher installation cost will be worth it in the long run.
A professional will consider the following factors that will affect your long-term savings:
- The size of your furnace
- The insulation levels in your home
- The condition of your home’s ductwork (if you have leaky ducts, you won’t see as much energy savings)
An important note — AFUE can drop over time.
If you decide to purchase a 95% AFUE furnace, the AFUE will probably decrease as the furnace ages, especially if the furnace is not maintained. If you’re considering a 95% AFUE furnace, it’s important to get annual maintenance so that the AFUE remains as high as possible.
Want a professional AFUE recommendation for your new furnace?
If you want to know exactly how much it would cost to install a high-efficiency furnace, we can help! Contact us and we’ll have an expert come out to inspect your home and give you an estimate.