A Systems Approach to Retrofiting Residential HVAC Systems

Over the past couple of years, a Best Practices Guideline for Residential HVAC Retrofits (PDF) has been developed by the US Department of Energy (DOE) to provide guidance for contractors in performing whole house retrofits. Because of the strongly cost-limited nature of retrofits, combined with the wide range of existing home performance, the DOE guideline has several levels of retrofit packages depending on the level of intervention that a homeowner can afford, or is justified by the condition of the home and its HVAC system. The packages are pre-selected combinations of individual retrofit activities that provide simple whole house guidance for contractors. This guideline has been evaluated by potential users such as contractors and weatherization experts. Part of this evaluation included a field pilot study applying the guidelines to eight test houses. The application of the guidelines to these houses resulted in feedback that helped to update and improve the guidelines. In order to have an independent assessment of the guidelines, two of the houses were evaluated by an independent energy efficiency contractor. One of the test houses was chosen to be retrofitted and had the Best Practices Guideline diagnostic screening tests repeated after the retrofit to compare pre and post-retrofit performance, as well as being the subject of extensive monitoring to determine the change in house performance due to the retrofit. More details of these test results and the application and development of the Retrofit Guide can be found in Walker [2003].