Polar Vortex Solution: Is a Modulating Furnace Always the Right Call?

Sarah Ward's picture
Sarah Ward
January 13, 2014

Last week's polar vortex caused many to seek out new heating options. What’s the best furnace choice?

Modulating furnaces
Modulating furnaces
Credit: dianaht via Flickr

The winter season began with an estimate by the US Energy Information Association (EIA) that more than 90 percent of the 116 million homes throughout the country would be challenged by higher heating costs in 2014 compared to last year. Turns out, they were right.

What the Washington Post termed a “large whirlpool in the atmosphere originating at the North Pole” and, perhaps ironically, the National Weather Service more simply called, “an arctic cold front,” (aka the "polar vortex") had much of the country staying indoors and bundled up last week. Bringing historically low temperatures - like 60 below with windchill in Montana - this brutal cold snap has home and commercial property owners alike looking for more effective, cost-efficient methods of heat.

While smart technologies like The Nest smart thermostat are making headlines, high efficiency furnaces, combined with better insulation, are often a more effective, long-term answer. But question number two is frequently whether a two-stage or modulating furnace system is most effective. Technically, it’s a bit of a false question because a two-stage system is a modulating system. The difference is relatively straightforward: a two-stage furnace operates only at two speeds, either 40% or 65% capacity and 100% capacity. A modulating furnace, on the other hand, is fully variable, constantly and selectively reacting to the home’s temperature by adjusting both the flame and blower.

In most cases, a modulating system is the way to go, offering quieter service and more consistent heating which leads to increased comfort. However, if your design is particularly small or dominated by open air planning, the extra cost compared to a two-stage system may not be worthwhile.

In addition to their applicability to the LEED CS SSc9 credit, high efficiency furnaces can help to earn as many as 19 points for LEED New Construction and Schools projects.  They can also contribute to the 21 available points for EAc2 in LEED Core and Shell. For a comprehensive list of ENERGY STAR Most Efficient 2014 furnaces, click here.


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