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Are Modulating Gas Furnaces Worth The Added Investment?

by Feride Halma

Gas furnaces are renowned for their efficiency, and while they are more expensive to purchase and install than electric or oil-fired furnaces, they can pay for themselves with their comparatively low running costs. However, cheaper, single-stage gas furnaces may not provide the kind of energy savings you are looking for.

Modulating gas furnaces, also known as multi-stage gas furnaces, are a relatively recent addition to the world of residential heating. They are more expensive than single or two-stage furnaces, but investing in a modulating furnace can be well worth the money. Here are three major advantages that make modulating gas furnaces an excellent investment for any home:

High Energy Efficiency

All gas furnaces sold in the U.S. are given an AFUE rating, or an Annual Fuel Utilization Efficiency rating, before they can be legally sold. This rating tells you how much of the fuel your furnace uses is transformed into useable heat, and is measured as a percentage.

Gas furnaces must meet a minimum AFUE rating of 80% before they can be sold, and all single and two-stage furnaces will meet or exceed this rating. However, choosing a furnace with a minimum efficiency rating means that up to 20% of the gas it burns will be lost, either as waste heat or as combustion byproducts. Many modern oil and electric furnaces exceed these ratings while costing less to purchase and install.

Modulating gas furnaces have the ability to automatically adjust combustion rates and blower fan speeds depending on your needs. This allows them to use their gas supplies in the most efficient way possible. When you need a small temperature adjustment, modulating furnaces run on lower power settings to conserve fuel. More dramatic temperature adjustments will kick the furnace into high-power mode for brief periods.

As a result, many modern modulating gas furnaces can achieve AFUE ratings between 90% and 95%, making them much more efficient than any oil or electric furnace. 15% more efficiency may not sound like much, but it can save you hundreds of dollars a year on your gas bills, especially if you live in a larger home with substantial heating requirements.

Quiet Functioning

Because modulating furnaces only activate their blower fans at full speed when absolutely necessary, they are usually much quieter than most single and two-stage gas furnaces. If you want your new furnace to provide heat without disturbing your peace and quiet, modulating gas furnaces are well worth the extra money.

Even Heating

Modulating gas furnaces are also useful for keeping your home at an even temperature, and will not cause the same dramatic temperature fluctuations as single and two-stage furnaces. Their ability to automatically adjust their heating power based on your needs can prevent sudden changes in temperature, and can also help to eliminate uncomfortable 'hot spots' directly beneath your ducting vents.