Many homes and businesses in Charleston today heat and cool multiple areas (or zones) from a single Furnace/Air Handler. Consider a home that has a large second story space with a smaller third story area, or a business with 3 offices and 1 large retail space. Rather than installing individual systems for each location (which is expensive), a single properly configured furnace/air Handler unit can do the job, when combined with a zone system.
With a multi zone system, multiple sections of a business or home structure can maintain set temperatures through the use of coordinated thermostats and dampers. Zone systems can be deployed with Electric, Natural Gas/ Propane (LP), or Geothermal HVAC systems. Managing the flow of air requires more mechanical parts, including electric dampers, zone panel boards, bypass dampers, and a thermostat for each zone. Some systems can address up to 8 zones within one Furnace/Air Handler configuration.
Zone systems can Condition one specific part of a structure without wasting energy trying to condition the remainder of the structure. The sophistication of the installed zone management componentry (which can include: a zone panel, a variable speed blower, bypass duct(s) and more) determines a system’s ability to address a variety of fluctuating conditions. The goal is to maximize performance with a minimum number of systems. Why add another system when you could just upsize the equipment (to correct tonnage) and zone each space correctly?
As with any system required to manage many variables, zone systems must be designed and installed correctly before maximum efficiency can be achieved. Each zone in a home or business requires a set amount of airflow, expressed as CFM (or Cubic Feet per Minute) to condition the zone to desired temperature ranges. The components of each zone must be configured to deliver the proper number of CFM to achieve success.
It is not unusual (but it is unfortunate) for home and business owners to experience VERY high utility bills due to a variety of problems including: improperly sized ducts, non-calculated CFM, poor airflow, and single speed blower drives. For example, if a two-zone structure is installed utilizing a single speed blower drive the motor will only operate at one speed. In other words, it does not fluctuate airflow when one zone opens or closes. This causes inappropriate (excess and poor) airflow to the supply ducts.
To realize the full potential of a zone system, IT IS A MUST that a Variable Speed Motor be included in the blower drive configuration. These motors operate using static pressure levels. As one zone closes, the pressure in the ducts rises, and the blower slows down. This helps the zone(s) that is open to satisfy much quicker saving the consumer money on energy costs.
Failure to achieve maximum efficiency with a zoning system is rarely an equipment issue. It is typically related to poor design or installation of the HVAC ducts, blower motor(s), and caused by a lack of knowledge on behalf of the contractors installing these systems.
One of the best Zone Panels in the industry is made by Honeywell. It has the capability to operate with any system, thermostat, and damper type. Many home/ business owners do not know what type of equipment they are relying on to keep them comfortable. With a digital/ LED display of zones the Honeywell zone panel portrays which zones are operating and under what mode they are operating.
This panel also comes with a 5 year manufacturer warranty. Another issue with improperly sized ducts in a zoned system is the inability to remove humidity (moisture) from the home. This results in failed blower motors in many cases due to excessive moisture exposure, and these motors can cost several hundred dollars.
It is imperative that each zone be tested for airflow performance throughout the structure if the consumer wants to keep energy costs to a minimum. In some cases a bypass duct will have to be installed to keep the static pressure in the ducts low when only small zones are operating. The best option when installing a bypass duct is to implement an external static pressure bypass damper.
This damper works off of static pressure (just like the variable speed blower) and modulates open/ closed according to the different pressures. This helps keep a system from short cycling and ultimately satisfying quicker.
As always, if you have any further questions about your HVAC system for your home or business in Charleston or the Lowcountry, feel free to give us a call: (843) 870-2076.