warm mother and daughterThe heating load in Georgia and South Carolina is significantly lower than in many other parts of the country, but even so, selecting some specific supplemental furnace equipment will improve your comfort. In our region, however, selecting a high-efficiency furnace will have a longer payback period because the heating season is short and mild.

Choosing a variable-speed furnace is one of the best decisions because the heat and air output adjust themselves based on your home’s need for heating. Most of the time, it will run at a lower, more continuous speed, which improves your comfort. A single-stage furnace runs on high, and when your home needs just a bit of heating, it will cycle on and off quickly. Rooms farther from the thermostat may still be chilly. With a variable-speed system, the air mixes better throughout the home for a longer period, and more remote spaces will be warmer.


In addition to better comfort control, you’ll receive these benefits with variable-speed supplemental furnace equipment:

  • Better air filtration. When the furnace runs longer, it will filter more of your home’s air, improving indoor air quality (IAQ). Any allergy sufferer in your home will appreciate the lower dust and pollen load throughout the winter.
  • Less temperature fluctuation. The longer running speed warms your home thoroughly, cutting back on wide temperature swings. You won’t feel that blast of cold air from the registers, since the furnace starts slowly and ramps itself up mid-cycle.
  • Noise control. The motors inside these systems operate much more quietly than a single-speed motor. This is a benefit you’ll enjoy year-round if your furnace houses the indoor parts for your air conditioning system.
  • Reduced electrical consumption. The slower running speed for the blower motor cuts down on the amount of electricity it uses.

Blower Motor

When you’re choosing a variable-speed system, you’ll have two options. The first is to choose one with a permanent split capacitor (PSC) motor that’s been programmed to run at two different speeds. The second, and far more energy-efficient, choice is one with an electronically commutated motor (ECM). These types of motors cost more initially, but pay for themselves in a relatively short time.

The most efficient ECMs may use up to 70 percent less electricity than a PSC. Even at top speed, they’re much quieter than a PSC. An ECM has such high efficiency because it’s engineered differently than a PSC. Instead of using alternating current (AC), the ECM has a converter that turns the power into direct current (DC). DC is a more efficient use of power than AC. Additionally, the ECM may not even need periodic oiling, since some models are made with sealed bearings.

Gas Distribution

The other part of the supplemental furnace equipment that’s part of the variable speed system is the gas orifice. It’s designed to adjust the amount of gas it sends into the burner. When you need a lot of heat, it will send more, but since it’s seldom that cold in this area, it will rarely need open completely.

Efficiency Ratings

The variable-speed furnace does not necessarily have a higher AFUE (annual fuel utilization efficiency) rating than other kinds. The minimum for all combustion furnaces stands at 78 percent and they can go as high as 98 percent. A system with an AFUE of 78 wastes 22 percent of the fuel it uses, while one with 98 will waste just 2 percent. Variable speed equipment is available with higher AFUE ratings that will give you additional energy savings.


Selecting this type of supplemental furnace equipment makes it possible for you to zone your home, which has significant benefits. A home with a zoning system has two or more designated areas that have their own thermostats. Two-story homes, those with sprawling wings, or a cluster of rooms that are seldom used benefit from a zoning system. Each zone has its own thermostat that opens an automated duct damper when conditioned air is needed in that area.

Having a zoning system with a variable speed furnace means that the furnace can keep up with heating requirements when demand is high. Conversely, if one zone doesn’t need heat but the others do, the furnace will lower its output.

To learn more about this supplemental furnace equipment, please contact us at Byrd Heating and Air Conditioning. We have been providing exceptional HVAC services for Savannah, Garden City and Tremont Park since 1986.

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