Final Report (PDF) March 2006
The Salt Lake Community Development Corporation (SLCDC) seeks to provide affordable housing for low-income families in Salt Lake City and the surrounding communities. In addition to reducing the first cost of the homes, the SLCDC recognizes the importance of reducing operating costs. For families to thrive, low-income homeowners must be able to operate and maintain their homes.
In 2004, the SLCDC developed three homes in Magna (two of which are the side-by-side prototypes evaluated by PATH). The Magna prototype design specifications include:
- Advanced framing techniques
- Low-e windows
- Compact duct design with central returns
- Properly sized HVAC equipment
- Direct- or power-vented mechanical equipment
- Air sealing
PATH evaluated the efficiency of a Freus evaporative condenser and compared it to a high performance (SEER 14) air cooled AC system in the protype houses. There was not a dramatic difference in performance between the two systems. This may be explained by the fact that air cooled equipment tends to be optimized for mild outdoor temperatures (SEER ratings are performed at 82F outdoor temperature).
The Freus realizes improved efficiency with evaporative cooling that is most significant at high outdoor air temperatures. Thus as outdoor temperature rises above 95F, the benefit of the Freus system compared to the SEER 14 system becomes more significant. The performance benefits of a Freus AC system compared to a SEER 14 AC system depend significantly on:
- outdoor air temperature,
- the availability of time of use electricity rates and
- utility financial incentives for peak demand reductions.
Most become important factors for any builder deciding between these two high performance AC system alternatives.
See the project profile for construction photos and status.
Content updated on 11/20/2006