This report is an initial investigation of the energy benefits of using advanced performance dedicated outside air systems (DOAS)—previously known as very high efficiency DOAS—in a multi-family building applications. Objectives for this report were to:
- Evaluate the energy benefits of a advanced performance DOAS configuration in multifamily buildings compared with conventional balanced ventilation systems (Washington State Energy Code) and exhaust driven systems (code minimum in Oregon, Idaho, Montana).
- Calculate the impacts of heat/energy recovery ventilation (HRV/ERVs) unit controls for bypass capabilities on energy use and indoor comfort.
Currently, multifamily housing is a growing sector of the design and construction industry across the Northwest. Best practice in multifamily housing for energy efficiency already focuses on actively providing ventilation air through dedicated systems, known as balanced ventilation, as opposed to the common practice of exhaust-driven ventilation where outdoor air is pulled through each apartment and exhausted. Balanced ventilation can be configured as large, centralized systems with ventilation air ducted to and from each apartment or through individual small units, known as a unitized system. This practice of using a dedicated unit or units for ventilation only is not a new concept for multi-family buildings, however, the potential for energy savings from using high efficiency HRV/ERVs, efficient controls like ventilation bypass, and efficient fans may provide a way to drive further energy savings.