The current 2016 Title-24 Building Energy Code Standards contains new indoor ventilation requirements. California has adopted the residential standards of ASHRAE 62.2 All low-rise residential buildings must have a whole house ventilation system that provides a calculated minimum amount of outdoor air by using either a continuously running bathroom fan or a supply or return air ventilation thru a central HVAC system. The minimum ventilation volume must be a minimum of 1 cfm for each 100 sq. ft. of floor area plus 7.5 cfm for each occupant. The number of occupants is determined by multiplying the number of bedrooms and then adding one. For example a 3 bedroom, 1,800 square foot townhouse would require 48 cfm of continuous ventilation. Additional calculations are required if the fan will be running intermittently thru-out the day as the fan will need to provide a larger airflow when running.
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Broan has introduced a bathroom fan/smart switch system that meets this requirement. It keeps track of the total usage of the fan thru-out the day and if fall short of the required number of air changes it will automatically turn on and run until the required airchanges have been satisfied. It also meets the maximum sound level requirement at 0.70 sones. It also coordinates with other fans normally installed in the house, such as the range hood to meet the calculated minimum cfm required. This new requirement takes effect January 1, 2010 when California adopts the 2008 Title-24 Building Energy Standards.
