Several factors must be considered when reviewing a purchase of a custom air handler. Following is a list showing a few common rules of thumb when considering a custom air handling solution.
Standard Commercial Grade Unit:

• Average design life with proper maintenance approximately 10 to 15 years (less in salt water and desert environments).
• Average cabinet leakage can exceed 5% of design CFM at no more than 5” of static pressure.
• Less dimensional / footprint flexibility results in lost and unusable space.
• Factory piping options not typically available.
• Factory installed, piped, or tested humidification not available.
• Factory sound, leak, and performance testing of assembled units not available.

• Average design life with proper maintenance estimated at 30+ years. Buy commercial grade units twice or a custom unit once. Not only do you have the cost of the unit but also the cost of the install.
• Average cabinet leakage does not exceed 1% of design CFM at over 10” of static pressure. Less leakage means more BTU’s in the building ductwork and not wasted in the mechanical space or outdoors in the case of rooftop units.
• Very flexible since each unit is a clean sheet of paper design. Units can be U-Shaped, T-Shaped, L-Shaped, round, columns in the air tunnel, stack, or nearly any other shape required to fit the project requirements. Build a building or renovate a space, use odd shaped units to gain more useable floor space.
• Factory piping is available. This saves the high cost of field piping and reduces the risk of air leaks in the unit casing around pipe connections.
• Full factory wiring to a single electric feed available, which saves money on electrical installation cost.
• Optional factory sound, leak, and performance testing of assembled units before shipment. This saves critical time and field labor on site.
• Building custom units is like having two construction sites at once. Unit can come completed with piping, wiring, controls, etc, ready for simple hook-up to utilities and you basically turn the system on.