EQUIPMENT SIZING & EFFICIENCY
In the past, the heating or cooling capacity of residential mechanical equipment was not selected based on the actual needs of the structure, but rather a potential discomfort complaint from the home owner. Mechanical equipment was oversized by 30% to 50%, and everyone was happy because the cost of energy was never considered.
The problem with this is, when a piece of equipment is oversized, it does not run efficiently. Cars again, are a good example of this situation. We get very poor gas milage driving slowly in heavy traffic, because the engine is designed to efficiently operating at high speeds. Energy efficient design requires exact sizing of heating and cooling equipment for the specific structure, and this is what the California Energy Commission intends to accomplish with its more stringent design requirements.
Improperly installed mechanical equipment is also addressed by the California Energy Commission, through its inclusion of functional inspections of installed equipment. These tests are done by a HERS Rater if required for compliance with the Energy Code, and include: Air Conditioner Refrigerant Charge Testing, Cooling Coil Air Flow, Air Handler Fan Watt Draw and others. If the equipment fails these tests, it has to be repaired by the installer, ensuring the energy efficiency expected by the home owner.
Only through proper sizing and installation verification can high efficiency mechanical equipment contribute significantly to the energy efficiency of a home.