Taking the Next Step in Efficiency
One factor that will be aided by the 13 SEER change, however, is the potential for growth in zone control.
SLOW TO STARTThe HVAC industry is the last holdout when it comes to accepting zone control as a viable product. For more than 50 years, zoning has been standard on every hydronic heating system using zone valves or circulators. Electric baseboard heating was an easy and popular method of zoning, except for the cost of electricity.
Today the modern radiant in-floor heating units are all zoned. Even auto industry commercials talk about offering individual driver and passenger temperature controls or multizone climate control for each row of seats.
Why is it taking so long for the residential and light commercial HVAC market to wake up to the fact that zone damper systems can provide proper temperature control, save a tremendous amount of energy when used properly, and add value to the cost of the HVAC system and the overall home?
In 2006, homeowners still complain about poor temperature control in the home. In the HVAC industry, many have failed to show the value of properly designed HVAC systems because too many would rather compete on price.
Consider the cost of a car back in the mid-1960s, when central air conditioning was just beginning to make its way into new homes. The average automobile price was $4,000. Today that similar car could cost well over $30,000. The cost of a furnace now as compared to then, however, is still roughly the same. The cost of metal, labor, and overhead, unfortunately, has not stayed the same.
COMFORT IS NECESSARYPrice aside, how often does the contractor go beyond what the customer wants, and sell the customer what he or she needs in order to have energy savings and whole-home comfort?
Zoning is taking the next step in providing that comfort. It can solve the extreme demands of heating the far back bedroom in winter, and cooling the sun-facing family room, with its large glass windows, during a late-August afternoon.
Zoning can be a great complement to a 13 SEER system. Because many higher-efficiency HVAC systems use variable-speed blowers, zoning (combined with setback thermostats and a properly designed bypass) can provide up to 40 percent energy savings over single-zone systems.
Here's how it works. When a zone calls for conditioned air, the dampers close for the other zones that are not calling. This increases the pressure throughout the system. The increase in pressure causes the blower to speed up and triggers the bypass pressure sensor to open the bypass damper. When the bypass damper opens, it relieves the increased static pressure, thereby lowering the blower speed. This lower speed provides smooth, quiet operation while conditioning the zone.
When all or a majority of the zones call for conditioned air, the corresponding zone dampers open; the bypass closes as the static pressure sensor detects the lower pressure in the duct system. The bypass helps ensure peak performance of HVAC equipment.
A modulating bypass damper controlled by the correct static pressure switch is the key to zoning any variable-speed blower system. Some static pressure switches don't provide this type of close control; they hunt back and forth for the correct pressure, which greatly shortens the life of the damper motor, in addition to the control.
A zoning system that uses motorized dampers for each zone is the most basic and cost-effective way to reduce heating-cooling costs. A simple two-position damper system can cost as little as $200 per zone, not including the cost of the thermostats. The best zoning systems are those that are compatible with any standard, off-the-shelf thermostat.
Zoning and high efficiency are a great combination to save energy without sacrificing comfort. Now is the time to sell zoning. If you don't, your competition will.
Dick Foster, president of ZoneFirst, is an industry veteran with more than 30 years in the HVAC industry. He may be reached at firstname.lastname@example.org.
Publication date: 05/15/2006