CSLB C-20 HVAC ContractorVentilation and Air DistributionHard
Per ASHRAE 62.2 whole-house mechanical ventilation requirements, a home has 1,800 square feet of conditioned floor area and 3 bedrooms. What is the minimum required continuous whole-house ventilation rate?
- A84 CFM
- B54 CFM
- C90 CFM
- D60 CFM
Show answer & explanationAnswer & explanation
Correct answer: A. 84 CFM
ASHRAE 62.2 formula: CFM = 0.03 × floor area + 7.5 × (bedrooms + 1) = 0.03 × 1,800 + 7.5 × (3+1) = 54 + 30 = 84 CFM continuous whole-house ventilation.
Why the other options are wrong
- B. This is only the floor-area component, omitting the bedroom factor.
- C. This slightly overstates the result from a rounding or formula error.
- D. This value doesn't match either component of the formula.
ASHRAE 62.2 Whole-House Ventilation
A formula-based standard requiring continuous mechanical ventilation calculated from floor area and number of bedrooms to maintain indoor air quality.
- Formula: CFM = 0.03×floor area + 7.5×(bedrooms+1)
- Applies to whole-house continuous ventilation systems
- Adopted by reference in Title 24 residential IAQ requirements
Memory trick: Point-oh-three times area, plus seven-point-five per body.