A field test involving 35 homes was performed in Texas between 2000 and 2003 to study the response of low-income homes in hot climates to weatherization performed as part of the U.S. Department of Energy’s Weatherization Assistance Program. Field test design, findings, and recommendations are documented in the final report: Texas Field Experiment: Performance of the Weatherization Assistance Program in Hot-Climate, Low-Income Homes (ORNL/CON-499).
Previous Program evaluations in hot climates based on analyzing monthly utility bills had been able to measure the space-heating savings occurring in hot-climate homes, but had not been able to detect any significant electric cooling savings. Therefore, a unique whole-house electric monitoring system was installed in each house of this study that allowed appliance-specific electric load data (including air conditioners) to be collected without installing meters on specific appliances, and one indoor temperature to be monitored. The monitoring system was called the Non-Intrusive Appliance Load Monitoring System (NIALMS), which is comprised of Single Point End-use Energy Disaggregation (SPEED) recorders and their accompanying software.
The study found that improved Program designs and the use of advanced energy audits resulted in better weatherization measures being installed (use of blower doors to guide the infiltration work, more frequent installation of attic insulation, and installation of wall insulation) in the study homes, improved space-heating savings performance compared to the Program as implemented in the hot climates in 1989, and more comfortable indoor temperatures. Based on this study, it was recommended that states in hot climates be encouraged to select from an expanded list of measures using advanced audits or other techniques.
Two key policy dilemmas for Texas and other hot-climate states were highlighted by the study for which guidance needs to be developed: (a) how to balance expenditures between installing cost-effective weatherization measures and performing health, safety, and repair items, and (b) health, safety, and repair items can have an adverse impact on energy savings, which further complicates the weatherization decision process.
Several occupant and equipment-related behaviors were observed in the field test homes that help explain why audits may over predict energy consumptions and savings, and why air-conditioning electricity savings are difficult to measure. These include: the occupants may choose not to run their heating or cooling equipment on certain days, especially under mild conditions, or during the day (e.g., when they are not home); a house may not have sufficient heating and/or or cooling capacity to maintain comfortable indoor temperatures, especially before weatherization; the entire house may not be heated and/or cooled, especially when space heaters or window air conditioners are used; and installed heating and/or cooling equipment may not be operational during parts of the winter or summer, especially before weatherization.