How much ventilation do I need?

 The American Society of Heating, Refrigeration and Air-Conditioning Engineering (ASHRAE recommends (in its Standard 62-1999, "Ventilation for Acceptable Indoor Air Quality") that homes receive .35 air changes per hour, but not less than 15 cubic feet per minute (cfm) per person. A common rule of thumb is the 15 cfm multiplied by number of bedrooms in the house plus one. For example, a 3 bedroom house would require at least 60 cfm of outdoor air. [(3 bedrooms + 1) x 15 cfm = 60 cfm]. Kitchens should have an intermittent exhaust capacity of 100 cfm; bathrooms an intermittent capacity of 50 cfm. (ASHRAE also notes that "dwellings with tight enclosures may require supplemental ventilation supply for fuel-burning appliances, including fireplaces and mechanically exhausted appliances. See information on combustion appliances.)

For a basic overview of ventilation, including different types ventilation systems, try the following resources:

• Homeowner's Guide to Ventilation. by the New York State Energy Research and Development Authority's (NYSERDA). In addition to a basic general discussion of ventilation, this document includes recommendations which are especially useful for homes in cold-climates.
   
• ENERGY STAR^® has finalized the ventilation fan specification. www.energystar.gov/index.cfm?c=vent_fans.pr_vent_fans
   
• Home Ventilation Guide. by the Home Ventilating Institute.
   
• Guide to Controlled Ventilation by the Oregon State University Extension Service at (503) 731-4104.
   
• "Home Ventilation Options for Home Builders  from Energy Source Builder.

For a detailed analysis of ventilation system options for new homes, see the Lawrence Berkeley National Laboratory report Recommended Ventilation Strategies for Energy-Efficient Production Homes.  Copies of ASHRAE Standard 62 are available from ASHRAE.

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