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The term “high efficiency” has become very popular today.
But what does this term truly mean?
Many people assume that any furnace labelled high efficiency is automatically going to be cheaper to operate.
But the true meaning is a little more complicated than that.
In this article, learn about what a high-efficiency furnace really is and how to know if this is the right furnace choice for your needs.
Understanding the Annual Fuel Utilization Efficiency (AFUE) Rating
According to the U.S. Energy Star program, the phrase “high efficiency” is a measure of performance output versus fuel (energy) input.
The official measure of input versus output on a seasonal basis is the AFUE, or annual fuel utilization efficiency, rating.
Every new furnace will bear a label showing its AFUE rating. For example, let’s say you see a furnace with an AFUE rating of 85. What this tells you is that the furnace will turn 85 percent of its fuel input into heat output. The other 15 percent will be lost somewhere along the way.
What Does High Efficiency Mean?
As a general rule, the phrase “high efficiency” simply means that the unit or appliance in question will outperform a standard model version of the same, all other factors remaining equal.
Canada’s EnerGuide program explains that a furnace that is considered to be highly efficient may deliver efficiency gains of anywhere from 78 percent to 98 percent over a standard model furnace unit.
A gas or propane high-efficiency furnace may deliver anywhere from 90 to 98 percent efficiency gains. An oil high-efficiency furnace may deliver anywhere from 78 to 96 percent efficiency gains.
Different Geographic Regions Have Different High-Efficiency Designations
Most people do not realize that what is considered high efficiency in one part of the country may not be considered as such in other geographic areas.
For example, as the U.S. Energy Star program explains, an Energy Star-certified furnace sold in the South will be designed to deliver efficiency gains of up to 11 percent over standard furnace models.
But an Energy Star-certified furnace sold in the North will be designed to deliver up to 15 percent efficiency increases over standard furnace models.
Here in Canada, current regulations state that any new furnace must deliver an AFUE of at least 90 percent.
Will a High-Efficiency Furnace Always Save You Money?
This is one of those grey areas where you can get into trouble buying more furnace than you really need.
Every furnace requires two sources of energy to operate: electricity to run the blower motor and either gas (natural gas or propane) or heating oil.
The AFUE rating the furnace bears relates to the second type of energy only: the gas or oil. And since the blower motor will be operating all year long if you also have a central (forced air) air conditioner, you really need to know how much it will cost to run your blower separate from running your furnace.
It may seem easy enough to resolve this dilemma by just choosing a furnace with a high-efficiency electric blower. However, not only will a high-efficiency blower increase the purchase price of the furnace, but it may also draw more electricity to run than what the size of your home requires.
Unless you have a background in residential HVAC and feel comfortable performing the heat loss/heat gain calculations to identify the optimal size and power of furnace for your home’s square footage and layout, this is usually where most homeowners call in an HVAC pro for help.
Other Factors That Impact How Efficiently Your Furnace Operates
Just because your new furnace bears an AFUE rating of 90 percent or greater does not necessarily mean you will get that level of performance from your new furnace.
There are other factors that can make a big impact on how well your furnace is able to generate heat for an affordable cost.
These are some of the major areas where homeowners end up paying more to run even a high-efficiency furnace:
Leaking, clogged, blocked or poorly routed ducts
Clogged, closed or blocked air registers and vents
Dirty air filters
Age and quality of home and duct insulation.
Presence/absence of weatherstripping and air leak sealing
A furnace or furnace filter becoming clogged with debris is guaranteed to make that unit more expensive to operate as well as create a home fire hazard.
Leaking ducts can let out up to 30 percent of warmed air before it ever reaches its final destination. Unsealed air leaks, degraded weatherstripping and old or missing insulation can also hike up heating bills.
The best approach to improving furnace efficiency and lowering energy costs is to do a comprehensive home energy audit before you even start shopping for a new furnace.
A home energy audit will alert you to other steps you can take (such as repairing and insulating your ducts and sealing up energy leaks) that will keep the warmed air you are paying for inside your space where it belongs.
Choosing the Right Furnace For Your Home
If your current furnace is at least 15 years old, current Energy Star guidelines recommend replacement. New furnaces can deliver up to 15 percent efficiency gains right out of the box.
But you still need to know how powerful your new furnace should be to handle the heating needs of your space. This is expressed in BTUs, or British thermal units.
Your HVAC contractor will use your home’s square footage to identify the furnace BTU capacity that best meets your needs.
Get in Touch
Do you need help choosing the right size and type of furnace that will operate at peak efficiency in your space? We can help!
Contact us online or give us a call at 905-549-4616.