The following is reprinted by permission from "THE INDEPENDENT HOME" © 1993 by Michael Potts.  I believe a newer addition is now available. His Solar Utilities Network is a very worthwhile visit!
Mobile Homes From an energy standpoint, it is hard to imagine a more miserable shelter than a mobile home. Using aluminum for lightness (a material that embodies enormous energy because it is refined in electric furnaces from bauxite, and is further cursed with good heat conduction properties), these thin-walled, barely insulated, single-glazed monstrosities are serious warts on the face of our nation. They are independent in the sense that their occupants can, at a whim, pump up the tires, kick out the blocks, and be gone, but they are horribly wasteful. In fact, their impermanence commits the occupants to a life of unwitting disconnection from the land their mobile hovels infest. To heat or cool a trailer requires roughly triple the energy used by a properly insulated house of equal size, and trailer residents, who invariably pay the energy bills, are condemned to perpetual slavery to the energy mongers because of this inefficiency. In a trying environment, it is practically impossible to operate anything but the smallest mobile home on an alternative energy system, because it takes too much energy to keep them warm or cool. Furthermore, they are firetraps and they are containers for a horrifying collection of toxic vapors. Evaluated by the freedoms enumerated in chapter 4 (rational construction costs with sustainable materials, reasonable expenses to operate and maintain, and a responsible way to recycle and abate the structure at the end of its useful life), the mobile home is a mistake from beginning to end. Significantly, elsewhere in the world, not even the most disadvantaged people consider them remotely habitable. Champions of the mobile home offer the excuse that these may be the only kind of habitation affordable to low-income folks. That's absurd. So much goes into making the damn things mobile that equal energy and equal care put into a stable dwelling would provide a much more functional and beautiful home at much less cost to the environment. It's also important to ask—to what extent have the lax health and safety standards applied to trailers made their existence possible, while similar relaxations have not been applied to solidly constructed low-income housing? The advice of many who had moved onto undeveloped land and lived in a trailer while building their home is, "Don't waste your time and money." Camp in a tent, and build a guest cabin to weather the first winter in, while you learn about your site firsthand.
RonKZ notes:  I doubt that Michael was referring to today's upper-level manufactured homes, right?  However, even the best-built & the best-insulated are unsuitable for "off-the-grid" use, due to their demands for conventional energy sources & systems, but worse still, their lack of thermal mass.  Sadly, the same applies to all frame buildings and even straw-bale homes!
Posted by RonKZ March 28, 2001