If you’re in the market for a new furnace, does it make sense to get the top of the line? Should you set your sights on upgrading to a 95 percent efficiency furnace to replace the one you have currently installed?
The answer isn’t quite as black and white as you would assume it to be. Instead, you should work with an HVAC technician who can evaluate your situation and help you determine the right purchase for your needs.
How does a 95 percent efficiency furnace compare to other models?
If you start to look around at furnaces, you’ll discover a standard efficiency furnace provides 80 percent annual fuel utilization efficiency (AFUE). What that means is that 20 percent of the energy produced by natural gas is expelled within the exhaust.
To receive a high efficiency rating, it will be rated at 90 percent or higher. A 95 percent AFUE is not uncommon in the newest gas-powered furnaces on the marketplace.
Just by looking at the numbers, it’s easy to assume that investing in a furnace with a higher AFUE would be more beneficial in helping you save energy, but it’s not as simple as that.
A standard furnace operates differently than a 95 percent efficiency furnace. An 80 percent furnace uses combustion to generate energy. It uses air from the surrounding area to function properly.
The 95 percent furnace doesn’t do that. Instead, it uses a sealed combustion process, meaning you’ll have to build a process where air is pulled from outside and flows into the furnace to create energy. Therein lies the problem. In older homes, it might not be worth the hassle.
If a furnace is located in a vented attic or crawl space, you probably won't make up the difference by switching from a standard furnace to a 95 percent furnace. The attic already has the vented air for the combustion process, and it would be difficult at best to install an outdoor air flow pathway.
Because the area where your 80 percent furnace is already well vented, gases produced from the combustion process don’t pose a safety risk. But by upgrading and sealing off the space, you could increase the likelihood of having exhaust problems in the future. Unvented areas pose more threat to having gas leaks and carbon monoxide problems.
That’s why location is so important.
What questions do you have about installing a new high efficiency furnace in your home?