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site-built, mobile/manfuactured and modular homes
What are the HUD-code requirements for mobile home ventilation?
Sunday, April 19, 2020
There are separate requirements for whole-house, kitchen, and bathroom ventilation:
•• Whole-house - HUD requires that a manufactured home have a whole-house ventilation system with a minimum capacity of 0.035 cubic feet per minute per square foot of floor area. So 1200 square foot home would require 0.035 x 1200 = 42 cfm fan capacity. But the code further states that it cannot be less than 50 cfm or more than 90cfm, so a 1200 square foot would need 50 cfm of mechanical ventilation.
The system must have a manual control that is labeled “WHOLE-HOUSE VENTILATION,” and cannot draw or exhaust air from the crawl space, floor, wall, or ceiling/roof assemblies. The ventilation system can be part of the home’s heating and cooling system, but must be capable of being operated separately. For more details, go to our blog post What is the HUD-code requirement for whole-house ventilation in a mobile home?
•• Kitchen - A kitchen exhaust fan must provide a minimum of 100 cfm and can be the through-the-wall exhaust type or a hood fan over the range ducted to the exterior.
•• Bathroom - The bathroom fan is required to move 50 cfm (cubic feet of air per minute). HUD did not require mechanical ventilation of kitchens and baths until the 1994 update of the HUD-code, but most manufacturers were already installing exhaust fans because of customer demand.
Both the kitchen and bathroom fans must have a backdraft damper, which is a hinged flap that closes when the fan is off to prevent air leakage, and relies on gravity to shut. See our blog post What are the ventilation requirements for bathrooms and kitchens in mobile homes? for further details.
Also, go to our HUD-CODE FOR MOBILE HOMES page for a listing of our other HUD-code articles.
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