I just moved into a new house. Of course, one of the first things I did was take a look at my furnace. It’s rated at 91%, which actually made me mad, because I was hoping for 95%. But that actually got me thinking about the way furnace efficiency standards have changed over the years.
A furnace sucks a lot of energy, but unless you just really like being cold, it’s a necessary evil. They use so much energy, though, that the Department of Energy has been keeping an eye on the numbers. They claim that almost 20% of energy that’s delivered to residential areas is used by furnaces. That’s a good chunk. And if your furnace is old, it’s going to use more. Here’s why.
National Appliance Energy Conservation Act of 1987
Way back in ’87 and before, there were no real standards to which furnaces were held, at least in regard to the amount of energy they used. So when the government enacted the National Appliance Energy Conservation Act of 1987, furnaces were one of the first appliances they reviewed. They set a minimum rating of 78%, based on annual fuel utilization efficiency. The minimum efficiency could range based on the type of furnace, but 78% was the most popular rating.
Think of it like this: if you put in 100 units of energy into your furnace, at the very minimum, the furnace has to output 78 units of heat. That went into place in 1992.
The Stringent 2000s
Come 2007, the DOE wanted to raise the minimum efficiency to 80%, which would go into effect in 2015. The thing is, most furnaces were already well above that energy standard, so it wouldn’t have done much. So a group of furnace manufacturers and advocates for energy efficiency (my kind of people) began pushing the DOE to make standards even more stringent in 2009.
One of the goals of this group was to divide efficiency standards into regions. That way, furnaces in North Dakota aren’t rated on the same scale as those in Louisiana—two entirely different climates. So the DOE decided to push those regional standards: 90% in cooler climates, 80% in warmer climates.
Condensing vs. Noncondensing Furnaces
But, this rule was challenged before it could go into place. There are two types of furnaces out there: condensing and noncondensing. Condensing furnaces are far more efficient than noncondensing, for a number of reasons, one of which is that condensing furnaces reuse heat that’s otherwise lost.
The thing is, in homes where noncondensing furnaces have been used, new technology has to be utilized in order to upgrade to condensing. That includes altering ductwork and ventilation systems, and maybe even modifying the hot water heater. These are all expensive fixes.
So in a settlement, the DOE backed off on these standards. So the rule is still 80% for non-weatherized gas furnaces. Check the minimum efficiency chart above for the minimum ratings for different types of furnaces.
What does this mean if you want to be green? Well, it’s simple: the higher your furnace’s efficiency, the less energy it will use. If green living is something incredibly important to you, then fronting the money to install a 90%+ furnace is a great step toward that lifestyle.