Can mobile home exterior walls be insulated without removing panels?

This is a post at Houzz from "James". He did the following to his home and it's exactly what you need:

"First I want to apologize for such a long post. But, this is something I have already experienced and thought I would share these ideas.

One of the most overlooked losses of heat is through the floor. Check the skirting around the trailer to see if it is vented. If it is, consider putting mostly non vented skirting on the north side or plant wind blocking year round shrubbery. We have a trailer in Weatherford TX that was freezing us to death until I did this.

Since you stated the insulation is falling off underneath, sounds like you have the same problems I had.

I cut the plastic canvas and removed all old insulation. It was all settled to the middle. Then I went and got some barrier foil insulation (foil lined bubble wrap) and stapled it about an inch below the subfloor in each space between the floor joists. Next, I got some plastic mesh screen for holding cellulose insulation and stretched it tight and fir stripped it across the floor joists and blew in cellulose insulation in between each floor joists. It wasn't easy but the difference it made was unbelievable.

Most lumber yards let you use the machine to blow in the insulation free if you buy the minimum amount of insulation. I had to buy 10 bales a 7.00 a bale.

While you are under there, you will be able to see all the water lines and the old HVAC ducting. If the ducting is seperated, either reattach the pieces back together or tape the holes off with foil tape. I would just tape them off unless you intend on replacing the HVAC. Then consider replacing the entire duct with flex duct. The ducting on most older trailers I have seen are uninsulated metal, leak air and are not very efficient. Mine was channeling cold air up through the floor where the registers were. While under there, it would be a good time to check the water lines as well...

Odds are, if you have a '78 model, the insulation in the ceiling is blown in. My '78 Breck had clear plastic stapled to the trusses and insulation blown on top of it. This was covered with 1/4" fiberboard. The interior walls were just paneling and thin fiberboard directly nailed to the the studs. We did take this out, rewire the entire trailer and go back with 7/16" OSB sheathing on the walls and ceiling. Then we blew regular drywall accoustics to the ceilings and walls and it looks like sheetrock inside.

One last thing to note... If the water heater has a door outside for access, consider removing the door and attaching a piece of ductboard (foil lined fiberglass insulation board)to its entire inside surface. Be sure to cut out for the vents if it is a gas or propane water heater.

James"

Good luck.