Sounds like we could have stolen the idea for this headline from the lead in to a weather report: "The replacement market looks variable to partly cloudy. New construction is currently sunny, but a low pressure system is working its way in from the south ..."

Alas, nothing so clever ... true variable-volume motors have been available in the industry since 1987, when GE Motors (now named GE ECM by Regal-Beloit) launched its ECMâ„¢ 1.0 product. True is the operative word here - permanent split capacitor (PSC) motors have long had multiple speed taps that allow for one of five airflow speed selections. Some have referred to these as variable-speed motors.

However, true variable-volume motors are capable of adjusting the motor's speed and torque based on indirect real-time sensing of the system's temperature and static pressure. And, this is done without the aid of ductwork sensors. They're actually pretty cool. But, you know that because you've been working on them for nearly 20 years.

However, did you know that the No. 1 determination regarding returned electronically commutated motors (ECM) is "no problem found" - about 40 percent of the time? That means users were replacing the motor to solve problems that actually lay somewhere else in the HVAC system itself, rather than the motor.

Please don't consider this an indictment of misdiagnosed systems and mistaken warranty claims. It's more an evaluation of future technology and what you might do to better prepare your company for the changes ahead.

Variable-speed technology is already a mainstay in many HVAC products coming off manufacturers' production lines today. There is a good chance that the high-efficiency indoor air handler you install this week is of the variable-speed type. Though outdoor condensing unit variable-speed motors have been around as long as their indoor counterparts, they are less well-known. With the onset of the 13 SEER efficiency standards, it is likely that variable-speed technologies will become even more the norm.

Technology Is Growing

The ideal HVAC system would be big - not oversized in its tonnage, but physically big. A big system provides for slower air movement, which is helpful to remove moisture from the airstream. However, "big" is cumbersome.

More-efficient indoor air handlers were enabled, in part, by more-efficient motors that allowed indoor coils to remain reasonable in size as efficiencies were increasing. As outdoor units are mandated to increase in efficiency, they will tend to get bigger - really big - oh, you've already seen one?

Of course, the 13-SEER units are about the same size as they ever were. But, have you tried to bend over the top of a 20-SEER unit? Variable-speed technology will also enable more reasonably sized outdoor coils as condensing unit efficiencies increase.

According to Paul Goldman, vice president and business leader for GE ECM, packaged systems are certain to be using more variable-speed motors. Most major manufacturers are using variable-speed motors, especially in their high-end product offerings. Carrier and Bryant use the GE ECM 2.5 motor exclusively in some furnaces and air handlers, especially those products that interface with their respective Infinity and Evolution control systems.

It has long been known that the replacement market represents more than 70 percent of residential HVAC business. Variable-speed technology will experience rapid growth because the replacement market continues to grow even larger, and high-efficiency products will populate the market within one equipment life cycle.

There is a lot of "inventory" sitting around in homes, waiting to be replaced. Understanding the technologies that are going to drive this industry in the coming years is important for continued success. Are contractors ready for that?

Perhaps not. Some manufacturers haven't communicated the distribution and commercialization of their own 13 SEER strategy yet.

Mike Murphy is editor-in-chief. He can be reached at 248-244-6446, 248-244-2905 (fax), or

Publication date: 03/28/2005