The Advantages Of Variable Speed & Modulating Hvac Furnace Technology
Lennox Variable-Speed
Furnace Technology
Furnace Technology
What is a variable speed hvac furnace?
A Standard Furnace cycles on and off frequently, so that you might typically experience temperature swings of 6 degrees or more in pockets of your home.
A Variable Speed HVAC Furnace contains a blower motor that is capable of moving at different speeds in order to more precisely control the flow of heated and cooled air throughout your home.
Improved airflow control from the variable speed blower motor can give you several benefits:
Increased comfort & efficiency with less noise
A Variable Speed HVAC Furnace will return increased comfort, increased efficiency, produce less noise and also enable more efficient zoning in your home:
- Increased Comfort: Variable Speed gas furnaces precisley regulate airflow to provide better control of temperature, humidity and air distribution throughout your home.
- Increased Efficiency: Compared to a conventional Single-Speed Furnace, a Variable Speed Furnace performs better and uses about 66% less electricity to power the fan motor. During heating operation you will gain heating efficiency (Annual Fuel Utilization Efficiency – AFUE). During cooling operation, variable speed technology typically results in an efficiency gain of 1 SEER (Seasonal Energy Efficiency Ratio). The higher the SEER, the lower your utility bills.
- Less Noise: A Variable Speed Furnace also ensures quieter operation. The furnace slowly ramps up to speed, so there’s no sudden “kick” or blast of air at startup.
- Zoning: Variable Speed Furnaces allow for more efficient zoning, which allows you to customize your comfort in different areas of your home and control your energy bills.
Improved indoor air quality
A Variable Speed Furnace will return cleaner air and enhanced humidity control for your family:
- Cleaner Air: When the furnace is not heating or cooling and the fan is in constant operation (indicated by the “Fan On” setting on your thermostat), a varible speed furnace will continue to slowly and inexpensively circulate air throughout your home. This allows your filters to capture more contaminants (because air is constantly filtering through them), so your family can breathe easier.
- Enhanced Humidity Control: When moisture levels are high, there’s a higher potential for mold growth and other pollutant problems. Compared to a single-speed furnace, a variable speed furnace is more effective at drawing moisture from the air for improved air quality and comfort.
More about how a variable speed furnace works
For any HVAC furnace, providing maximum comfort means achieving the proper amount of airflow. This is true for both heating and cooling operation.
Unlike conventional single-speed blower motors, a variable speed motor runs at a wide range of speeds. Using intelligent technology, it continually monitors incoming data from your heating and cooling system, and it automatically makes the adjustments necessary to meet your comfort needs.
The furnace blower motor varies the amount of air circulated, compensating for factors like dirty filters by increasing speed. Put simply, it delivers just the right amount of air necessary to provide the desired level of heating and cooling comfort.
source: Lennox International, Inc.
Calculate your potential energy savings
A variable speed motor will typically use only about 75 Watts of power per hour, compared to a conventional blower that uses about 400 Watts. Thus, over the course of one year, you can expect to save a significant amount of money on your electric bill if you invest in a Variable Speeed Furnace.
Use this simple formula to calculate your potential energy savings, based upon your existing power costs per kilowatt-hour:
Typical Example: 2,847 kW* x $.14/kW/h = up to $398 in energy savings per year in Western New York.
Note: Savings are based on an HVAC system that is always operating either in heating, cooling, or “Fan On” mode. Approximate annual savings for a system run only during heating season would be $120 in Western New York.
*Average kilowatts saved per year is calculated by saving 325 Watts of power per hour with a variable speed motor using 75 Watts per hour, versus conventional blower motors using 400 Watts per hour, times 8,760 hours in a year, equals 2,847,000 Watts/1000, which equals 2,847 kilowatts.
Modulating variable speed furnaces
The most sophisticated Variable Speed 2-Stage Furnaces in today’s marketplace contain a Modulating Gas Valve that can improve operation in the heating mode. These Modulating Furnaces reduce temperature fluctuations to provide even more consistent comfort, even quieter operation, and even higher heating efficiency – up to 98% AFUE.
The heating mode in a Modulating Furnace begins with the modulating gas valve open 100% and the blower fan at 0% speed. The gas valve then reduces gas flow to the burners as the the blower fan increases speed, so that the furnace automatically adjusts between 35% and 100% of heating capacity in small increments to maintain maximum heating efficiency. By continuously regulating the amount of fuel burned, according to the thermostat setting, temperature can be maintained to within about ½ degree of your thermostat’s set point throughout your home. Additionally, since the fan and the gas burner almost never run at 100% full capacity together, the on/off cycling that is typical of a standard furnace can be completely eliminated – making these modulating furnaces the most fuel-efficient technology currently available.
Choosing a variable speed furnace for your home
When combined with 2-Stage Furnace Technology, a Variable Speed Motor represents a significant upgrade for your HVAC system. Addition of a Modulating Gas Valve brings you to the current pinnacle in home comfort and energy efficiency. If you want, and expect, high-level performance from your home comfort equipment, then a Variable Speed 2-Stage Furnace or a Modulating Variable Speed 2-Stage Furnace may be the optimum choice for your family.
The HVAC Experts at Adema Heating & Air Conditioning can help you choose the optimum furnace for your home, that will maintain your comfort and will actually return on your investment by significantly reducing your heating bills year after year after year. We also include a Digital Programmable Thermostat with every new HVAC installation to maximize your return from your new HVAC system.