Duct Work and Crossover Duct
The problem I see most with mobile home ductwork is where the boot from the trough comes through the floor, especially if any flooring or floor repairs have been done around the ductwork. Quite often there is a gap between the mobile home ductwork boot and the floor causing an ductwork air leak. This can usually be sealed with a good quality duct tape or silicon caulking, however mastic is the ideal way to do it. Be sure that there is not any damage to the trough that usually runs the entire length of the mobile home, in the case of double wides there are two troughs interconnected by a crossover. The double wide mobile home crossover duct is usually a 14" or 16" flexible insulated duct. You can easily check for trough leaks by going underneath while the air conditioner is on and if you can find a location to stick your hand up through the belly wrap or belly board. If between the insulation and the floor you feel air flowing or cold air you may have a mobile home ductwork leak that will require further investigation or the calling of a expert. I completely removed the trough and installed the boots used in standard homes with flexible duct attached to a main trunk line from the heating and A/C unit as it is done in standard homes.Works great and is much more efficient.
Mobile Home Ductwork Insulation
I get lots of questions about how to insulate the ductwork on a mobile home or manufactured home. Below I have included a picture of the ideal way to insulate the main ductwork trough. The picture shows an ideal situation where you have access completely around the ductwork. This is not always the case. You can however wrap all of the ductwork that you can and the staple the insulation to the floor or joists in a cradling fashion. Then insulate underneath the mobile home as suggested on the mobile home insulation page.
Mobile Home Ductwork Manufactured Home Ductwork