Critical Examination of Ducted Mechanical Ventilation in New Residential Housing in the Pacific Northwest

摘要

Several programs have been undertaken in the Pacific Northwest Region to demonstrate new energy-efficient housing construction practices. These programs, sponsored by the Bonneville Power Administration (BPA), have spawned the construction of hundreds of tight, energy-efficient single-family, multifamily, and manufactured homes that are equipped with mechanical ventilation equipment, primarily a whole-house air-to-air heat exchanger (AAHX). The design and installation of an AAHX is a new and developing technology in the Northwest. Although builders received instruction and guidance in installing an AAHX, field data indicates that many of the early installations did not perform as designed. Specifically, in many dwellings, the location of fresh air intake and exhaust ducts was less than optimum, resulting in exhaust air being pulled into the dwelling through the fresh air intake. This paper critically examines AAHX installations in several dwelling types. Field data taken in two energy-efficient manufactured homes showed a significant improvement in fresh air exchange rate after relocating the exhaust air duct of the AAHX in each home. The whole-house air exchange rates, measured by tracer gas, increased by greater than 50/percent/ in each home after the exhaust ducts were moved away from the intake ducts. The duct relocation significantly reduced the probability of contaminated air entering the fresh air intake duct. This experiment has led to developing improved proposed guidelines for design and installation of mechanical ventilation equipment in energy-efficient manufactured homes. 23 refs. (ERA citation 13:048875)