Unlike in a modulating furnace, the burner in a standard-efficiency gas-fired furnace operates at 100 percent output whenever it’s lit — regardless of your home’s changing heating requirements. That’s one reason standard furnaces never exceed an AFUE (annual fuel utilization efficiency) percentage in the 80s. The AFUE expresses the percentage of fuel consumed by a furnace that actually produces usable heat versus the percentage lost due to inefficiencies of the combustion process. A burner continuously operating at 100 percent output does not fine-tune for energy efficiency across a wide range of temperature requirements.
High-efficiency furnaces incorporate modulating burners that adjust output according to continuous thermostat updates. The gas valve modifies burner output between 40 percent and 100 percent in response to input from the “smart” thermostat that calculates the most energy-efficient output to meet the temperature setting. Today’s high-efficiency furnaces have AFUE ratings that start at 90 percent and go as high as 98 percent.
In addition to adjusting burner output, a high-efficiency modulating furnace offers other energy-saving, comfort-enhancing advantages:
- A secondary heat exchanger extracts additional heat energy from the condensation of hot combustion gases. This results in up to 30 percent lower fuel consumption than standard efficiency furnaces.
- A variable speed blower incorporates electronically commutated motor (ECM) technology that alters blower speed and volume according to signals from a controller or programmed presets. While standard blowers cycle on and off, an ECM blower runs almost continuously at varying speeds for more consistent heating and lower energy consumption.
- Sealed combustion draws air from the exterior of the house through a pipe to the combustion chamber. Standard furnaces draw air for the combustion process directly from your home’s interior. This reduces the humidity in already uncomfortably dry winter air. It also means a cracked heat exchanger could allow the potential infiltration of combustion by-products like carbon monoxide into your living spaces.
Serving Lorain, Erie and Cuyahoga counties with over 50 years of combined HVAC experience, Energy 1 Heating & Air Conditioning is your local source of HVAC installation and service. Ask us about more benefits of upgrading to a modulating furnace.
Our goal is to help educate our customers in Lorain, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about Modulating Furnaces and other HVAC topics, download our free Home Comfort Resource guide.
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Energy 1 Heating & Air Conditioning
1 (440) 246-5440
Serving the Lorain, OH Area