Project Report

Assessment of HVAC Installations in New Homes
in APS Service Territory

Prepared for Arizona Public Service Company
Report dated: April 22, 1996
Prepared by Proctor Engineering Group
Contributors: Michael Blasnik, Tom Downey, John Proctor, P.E. and George Peterson, P.E.

Executive Summary

This investigation has involved field testing the air conditioning units, duct systems, and building shells of a sample of newly built houses; monitoring the performance of these systems; assessing achievable improvements to the systems; and analyzing the potential energy savings and peak demand reductions from such improvements. The investigation found that newly constructed homes in APS's service territory have substantial deficiencies in their air conditioning systems, similar to those found in studies from other parts of the country (Appendix A in the full report contains brief descriptions of related studies). Improvements can be made to provide lower energy usage and reduced demand while improving occupant comfort and satisfaction. These improvements can be accomplished at moderate cost.

The key findings of this study include:

• Duct leakage and existing duct insulation levels reduce overall cooling efficiency. Reasonable improvements can save 16% of the cooling energy for about $140
• Air conditioners often have insufficient air flow across the indoor coil and are frequently undercharged. Proper installation (following the manufacturers installation instructions) and testing would remedy these problems at a cost of about $70
• A program which ensures tight, well-insulated ducts and properly installed efficient air conditioners could reduce cooling usage by approximately 42% and diversified peak demand by 1.2 kW. The additional cost is estimated to be $210 per unit
• With properly installed systems featuring well insulated tight ducts the air conditioners should be resized to take advantage of the lower load. This would lower cost, "lock in" the peak reduction and further reduce the peak demand.

These results are supported by extensive information gathered in this project as well as data from projects in other climates similar to Phoenix. APS has a variety of potentially worthwhile options to pursue for improving cooling efficiency and reducing peak demand. Proper program design, training, and quality assurance are critical issues for actually achieving these improvements.

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