Goodman furnace

All About Furnace Efficiency

In Heating & Cooling 101 by Allan WLeave a Comment

High efficiency (HE) furnaces are becoming increasingly popular as of late and rightfully so. The benefits of lower energy bills, smaller environmental impact as well as the overall joy of knowing you have a brand new, clean running, high functioning furnace keeping you at a warm and enjoyable temperature is difficult to beat.

So let’s look at what a HE furnace is and we’ll even provide some tips on getting the most out of your new or existing furnace.
How do I know whether or not my furnace is efficient?

Besides the obvious answer such as finding your model number and ‘googling’ it, if your furnace is visibly or blatantly older, chances are it may not be the most efficient. Has your pilot light ever gone out requiring you to manually re light it? This may be another way to help you identify whether or not you have a  low-efficiency furnace. These units operated by the continuous use of a pilot light. A typical gas furnace made in the early 1970s has an AFUE (Annual Fuel Utilization Efficiency rating) of about 65 percent. Today, the lowest efficiency allowed by law for new gas furnaces is 78 percent, and the most efficient models have an AFUE of about 97 percent such as those found here.. As you can see, furnaces have become far more energy efficient over the years.


Even if you currently do not have the means, or the need to purchase the highest efficiency furnace out there, that doesn’t mean the units you’re left with are going to drain your energy bills and be just as inefficient as your old one. has plenty of furnaces from Goodman and Aire Flo that still boast terrific efficiencies at lower prices than the highest HE you can buy.


Goodman furnace

This Goodman brand model GMVM970603BN 60,000 BTU/h furnace is a terrific example of a high efficiency furnace. This particular model boasts a 97.0% AFUE.


What does the Annual Fuel Utilization Efficiency rating (AFUE) mean?

High-efficiency furnaces use two heat exchangers. Condensing units remove water from exhaust gas and then send the gas through the second exchanger for greater efficiency.

If a furnace is rated at 80% AFUE such as these, 20% of the energy used is lost, and 80% actually becomes heat.  To distill it down to a sentence, It is a ratio explaining the amount of fuel converted to heat and the amount of fuel which is entering the furnace. The conventional furnace heat exchanger does not extract as much heat from the fuel combustion process as possible, so obviously, the higher the AFUE the more efficient the furnace.


Many furnaces with an AFUE of 90 percent and more can get pricey, it only makes sense that the price of a furnace will rise with its fuel efficiency. So besides questions such as “what are the current needs in your home” you and your contractor must also look at the economic value of an ultra-high efficiency furnace. Chances are, where they’re really going to be cost effective is for homes located in areas where the winters are especially cold.

The price of a furnace with a 97 percent AFUE can cost about $1,000 more than a similarly sized unit with an 80 percent AFUE. However, depending on your old furnace, utility rates, your climate as well as how well your home is insulated/retains heat, the additional cost of the HE furnace can oftentimes be regained by your lower energy bills.

Your contractor should be able to calculate annual costs to operate the furnaces specifically for you home depending on your needs, circumstances and application. These figures will aid you in your buying decision when it comes time to select a brand/model. Additionally you’re always welcome to call us here at at 1-800-880-0199 Monday through Friday 9am to 5pm or email at

He can complete these calculations by plugging information on the unit, electrical consumption, and on characteristics of your home to provide an estimate about your potential new furnace’s affect on your utility bills.

Depending on your application, a ductless mini split system from Fujitsu or Mitsubishi may suit your needs or perhaps even a high velocity system from brands such as Spacepak and Unico  may also suit your application such as pictured below.
spacepak, high velocity

This is an example of a Spacepak high velocity 2.5 ton unit which can be viewed here


samsung, mini split

Here is an example of a Samsung 1.5 ton dual zone mini split system. This particular model can be seen here

It’s about your needs

Whether the furnace that fits your needs is an 80% a 92% or all the way up to 97%, it is all about what you need and what is best for your home. As you can see, there are many factors to consider when choosing which furnace is right for you and luckily you have folks like us along with the help of your contractor to get the right fit for your home and to ensure comfort and quality for years to come. We’re always here to help in the decision making for any of your HVAC needs so don’t hesitate to check our F.A.Q page or Call/Email us with any questions.

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