Whole-house mechanical ventilation is the intentional exchange of indoor air with fresh outdoor air at a controlled rate using fans. The purpose of whole-house mechanical ventilation is to improve indoor air quality.
Historically, mechanical ventilation was limited to local-exhaust (kitchen and bath exhaust fans) for spot control of moisture and odors. Houses commonly had enough natural ventilation, through leaky building enclosures, that whole-house mechanical ventilation was not necessary. Houses have become significantly tighter during the past 15-20 years as a result of changing codes, energy efficiency programs, and an overall desire to reduce energy use. Above-code programs and more recently the building codes have generally made controlled whole-house mechanical ventilation a requirement.
This Home Innovation TechNote describes the types of whole-house mechanical ventilation, the benefits of each type, the performance and cost considerations, related code requirements, and provides recommendations for those who are considering incorporating these systems in the homes they build.