Industry Focuses on Variable-Speed
“An especially warm summer, high energy prices, efficiency legislation - any one of these issues would have had a major impact on the HVAC industry in the past year, but the combination has led to tremendous focus on technologies that offer increased energy efficiency, unit size reduction, and better comfort features for consumers,” said Paul Selking, residential HVAC industry leader for GE ECM by Regal-Beloit.
With the ability to control humidity, increase the comfort level in the home, improve IAQ, and lower energy costs, a variety of two-stage and variable-speed products are leading manufacturers’ development focus.
WELCOME TO THE 21ST CENTURYWith over 50 years of leading the HVAC industry, single-speed technologies like the conventional induction motor are beginning to show signs of extinction. Though there remains a viable market for the forseeable future, compared with newer technologies like the electronically commutated motor (ECM), induction motors suffer from inherent inefficiencies. An induction motor is inherently less efficient than an ECM because they induce a current in the rotor, creating losses in the form of heat that must then be removed by the cooling system. Conversely, an ECM’s permanent-magnet rotor design only requires commutation to a stator winding, resulting in a motor that runs cooler, is quiet, and has a nearly linear current-to-output relationship.
Premium ECM motors also offer programmability and a wider speed range. In addition, an ECM-driven air conditioner is better at removing humidity because the blower can adjust airflow to lengthen the cooling cycle, while field-adjustable runtime profiles increase cooling efficiency and allow for more moisture removal.
Dehumidification is no small part of the efficiency equation, as latent heat extraction means that homeowners may set back the thermostat, reducing their energy bills between 3 and 6 percent per degree, according to the Environmental Protection Agency’s (EPA’s) Energy Star program. In addition to humidity management, these systems use less energy at the lower speeds of constant fan mode. Maintaining constant airflow efficiently reduces temperature stratification and counteracts issues such as undersized ductwork or loaded air filters.
Even without the advanced airflow management features available in premium ECM motors, a standard ECM motor like the X13 still offers up to 200 percent greater efficiency than a comparable induction motor. This performance leap has become especially important with the 13 SEER mandate, and many manufacturers have used these motors to help meet the higher efficiency requirement.
“We developed standard ECM motors as a cost-effective option to help meet the 13 SEER mandate,” said Selking. “Many OEMs have used the X13 in lieu of adding a more expensive coil heat exchanger, and an added benefit is that the high-efficiency motor has helped to keep unit sizes smaller.”
Size reduction is an important consideration for manufacturers, as 13 SEER units can be up to 30 percent larger in comparison to 10 SEER. With increases in costs for copper and aluminum, advanced technologies like ECM can make a significant difference in material expenses. At the same time, the bigger units create warehousing and logistic problems for the distributors and contractors who buy and install these larger systems. Smaller systems allow for smaller vehicles and transportation crews, fewer installations where a wall must be removed or ductwork is modified extensively, and faster installation times.
ENERGY SENSITIVITYEnergy costs are always a hot-button issue to consumers, but this was especially true over the past year. The biggest issue by far was gasoline prices, but consumers who felt a crunch at the gas pump also started examining monthly cost-of-living expenses. Moreover, media attention to energy issues was nearly constant between discussions on global warming, blackouts in the Midwest and New York, alternate fuel sources, the summertime heat wave, and higher electricity, oil and natural gas prices.
As more and more people examine the long-term costs of HVAC equipment, there is a natural tendency towards variable-speed units. Buyers also consider the efficiency-to-cost difference between low-tier and mid-tier systems.
Selking said, “Compared to a 10 SEER world, the price jump from 13 SEER to a higher-rated unit is much easier for consumers to handle. As a result, a surprising number of consumers have opted for the lower operating costs afforded by 14, 15, and even 16 SEER units.”
Beyond energy savings, new tax legislation has also created incentives to buy premium equipment. Internal Revenue Service (IRS) guidelines from the 2005 EPAct went into effect last year, including tax credits for certain furnaces, air conditioners, heat pumps, geothermal systems, and top-efficiency blower motors.
There is little question that future bills will continue the trend of tightened efficiency guidelines. Consumers and legislators alike are interested in conservation initiatives such as Energy Star, Zero-Energy Buildings, and the Building America program.
In the end, industry trends always follow the needs of consumers. While nobody can know what will happen with legislation, climate changes, or developing technologies, one thing is absolutely certain - consumers will always move towards the greatest value in the equipment they buy.
That’s why manufacturers everywhere are building systems that feature the benefits of variable-speed: by offering humidity control, better IAQ, increased comfort, and lower energy costs.
For more information, visit www.thedealertoolbox.com
Publication date: 04/09/2007