Mobile/Manufactured Home HVAC System – Or Site Built System – Is There Really a Difference

Short answer – absolutely yes. Longer version:

One of the single most critical considerations that any technician needs to understand relevant to diagnostics of issues with mobile and manufactured heating and cooling systems is the design difference between these systems and site built systems.

Smaller – Sealed Combustion Systems

Forced air downflow furnaces are the most commonly installed heating systems found in manufactured homes, as a matter of necessity more than anything – with few exceptions being allowed for modular and double wide structures, there are no crawls or attics allocated for equipment installation. Manufactured housing furnaces typically require the technician to disassemble the burner area of the equipment to access HSI’s (hot surface ignitors, thermocouples, etc).

• Adding Air Conditioning

• Adding a new air conditioner to a mobile home can be a challenge. Some mobile homes may lack ductwork and floor or ceiling vents, making a window unit or self-contained air conditioner the only choice. Other homes feature ducts running to the furnace, in which case cooling coils can be installed inside the furnace cabinet itself. Newer mobile homes that come with a full air conditioning unit installed simply require replacement of the unit outside the home, unless the thermostat or ductwork is damaged.

• Crossover Ducts

  • Many mobile homes feature crossover ducts, which are large flexible ducts that run under the house. These ducts transfer warm and cool area to level out the overall temperature in the house. Due to limited attic or ceiling space, most installers run these ducts in the crawl space. Unfortunately, this leaves them susceptible to damage from water and rodents. If your mobile home’s heating or cooling vents are not putting out the amount of air that they used to, check the crossover ducts for leaks or disconnected sections.