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.

The whole-houe ventilation requirements are typically met by manufacturers with a small, low volume fan behind a grille in the ceiling of a hallway that exhausts out the roof or a fresh-air intake duct from the roof that connects to the return air plenum of the furnace or air handler. The requirement that it be be able to be operated separately is fulfilled by setting the air handler fan at “ON” at the thermostat if the heating/cooling system is off.

    Here’s the full text of the HUD whole-house ventilation requirements at 24 CFR 3280:

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Want to learn more about inspecting
manufactured/mobile homes? 
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    Also, go to our HUD-CODE FOR MOBILE HOMES page for a listing of our other HUD-code articles.

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? 

• What is a D-sticker mobile home? 

• What are the tie-down requirements for a mobile home?

• How fireproof is a mobile home?  

• Can I install a mobile home myself?

• What is a Park Model mobile home?  

• Does an addition to a mobile home have to comply with the HUD Code? 

• What walls can I remove in a mobile home?

• What can I do to prevent dampness and mold in my mobile home? 

• How can I tell if a mobile home is well constructed?

• 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.