July 28, 2018

You often hear about how furnaces with an annual fuel utilization efficiency (AFUE) rating of 95 percent are highly efficient. Yet, you never hear about one with a 100-percent AFUE.

Efficient Furnace Repair in Ramsey, MN Helps Optimize Your Investment

That’s because there’s no such thing, as an article in The PennState Department of Energy and Mineral Engineering explains:

The energy efficiency of a furnace is not 100 percent. Not all the energy from the fuel is released, and not all the heat is available to heat the place.

No matter how well-designed a furnace is, some heat simply won’t make it to the house. As the furnace releases hot combustion gases, some of it escapes through the chimney instead. The AFUE measures how much heat your furnace loses. A 95 percent AFUE means 5 percent of the heat produced by combustion is lost.

To fully oxidize natural gas, experts estimate 1,000 cubic feet of combustion air is needed to interact with 100 cubic feet of natural gas. However, as some of the heated air escapes as stack or flue gas, more air is needed to get the right heating for the room and to get rid of the combustion’s toxic emissions.


The lost heat is thus highly justified and necessary. Most furnaces have AFUE ratings of 80 to 95 percent, a far cry from the furnaces of the 1980s and earlier decades, which hardly reached 75 percent. You can enjoy a significant reduction in energy bills with the most efficient furnaces your money can buy.

Lennox offers a furnace that many believe has the highest AFUE rating in the market today: the SLP98V Variable-Capacity. With an AFUE of up to 98.2 percent, this unit can achieve savings of as much as $800 a year, with self-adjusting systems that enhance its fuel-efficient design

The SLP98V is available at select Ramsey, MN furnace repair companies like Liberty Comfort Systems, who can also install the unit at your home, and provide the necessary maintenance for it.

Maintenance Still a Must

Regardless of efficiency, it’s still important to give any furnace the maintenance it needs to keep it in top condition. Incomplete combustion, for instance, can leave toxic residues in the HVAC system and emit deadly gases, like carbon monoxide. Furthermore, high-efficiency furnaces would be very expensive to replace, so a good maintenance system will help ensure their longevity and optimal use.

At the earliest signs of problems, make sure to get reliable Coon Rapids, MN furnace repair services at once, so that any defect or damage is detected and corrected early enough. A few trusted HVAC companies offer emergency repairs 24/7 to allow you to sleep tight amidst the northerly cold, regardless of who installed the system.

(Source: Heating Efficiency, Pennsylvania State University)

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