4. PROVE PERFORMANCE
The fourth tune-up item is actually a series of tests for your HVAC systems, which can be conducted by a knowledgeable, certified HVAC contractor or by an energy rater. The process starts by having heat loss, heat gain, and duct designs done for each of the house models you produce. Then, near completion of the home at minimum the following tests should be completed on the HVAC system:
Measure the total air flow of the furnace or air handler and compare it with the design requirements and the manufacturer’s specifications. There are a couple of methods and different types of equipment that can be used for this. For example, it can be done with the same piece of equipment used to measure duct leakage—another test that is recommended.
Measure and adjust air flows at each supply diffuser or grille to match the heat loss and gain air flow requirements.
Measure the pressure across rooms with doors closed to ensure adequate return air pathways.
Measure duct leakage using a device called a “duct blaster.” Like a mini blower door, the device pressurizes ductwork and allows for calculation of air leakage in the duct system. Air leakage of less than 6% to 10% is normally the goal within comprehensive green programs.
Check the refrigerant charge in the air conditioning system to be sure it matches manufacturer specifications.
These HVAC-system checks require a one-time expense for test equipment ranging from $3,000 to $5,000 and will take up to 1.5 hours to complete on a typical home. With the ever-increasing expectations of home buyers with respect to comfort and performance, I consider this a good investment; ask your HVAC contractor to invest in the equipment and training to do this or contract with an energy rater to do this work.