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. 

• • • • • • • • • • • • • • • • • • • • • • 

Want to learn more about inspecting
manufactured/mobile homes? 
Get our Handbook for 
Manufactured Home Inspectors 
at amazon.com for $19.95

• • • • • • • • • • • • • • • • • • • • • • 

Here’s links to a collection of our blog posts about MOBILE/MANUFACTURED HOMES: 

• Where can I file a complaint if I have problems with my new or used manufactured/mobile home in Florida?

• What are the most common defects in mobile/manufactured home foundation piers?

• How do I determine the age of a very old mobile home?

• What is a "HUD label verification letter" for a mobile/manufactured home?  

• When did a ground cover vapor barrier (plastic sheet) become required under a mobile/manufactured home? 

• Is it safe to go under a mobile home? 

• Are older mobile homes unsafe? 

• What do I need to know about buying a foreclosed mobile home? 

• Does it make sense to buy an older mobile home and remodel it? 

• Where do I find the vehicle identification number (VIN) on a mobile home? 

• How do I find out how old a mobile home is and who manufactured it?

• What is the right price for a used mobile home?

• How energy efficient is a mobile home?

• When were the first double-wide mobile homes manufactured?

• How do I upgrade my old (pre-1976) mobile home to meet HUD standards?

• What size air conditioner is right for my mobile home? 

• Can you move an older mobile home in Florida? 

• What does the HUD tag look like and where do I find it on a mobile home? 

• Can you put a zone 1 mobile home in Florida?

• How can I remove water under my mobile home?

• What's the differences between a trailer, a mobile home, a manufactured home, and a modular home? 

• How can I tell the difference between a manufactured home and a modular home?

       Visit our MOBILE/MANUFACTURED HOMES  page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.