Not all trailers are built to the same standards. I lived in one in cold North New Mexico and found it was designed for South Texas.
The walls consisted of one sheet of aluminum, one thin sheet of fiberglass (no backing) one sheet of paneling inside. Froze my butt off that winter! Never again!
On the other hand, a trailer built to Colorado standards was warm and snug.
I’ve also lived in stick built houses that were just as cold as the Texas trailer house. Now I live in an old oak built house with blown in insulation that is so warm in winter it is nice!
We used to have a trailer manufacturer north of here. Their trailers were junk. While a trucker was pulling one down the road, the welds on the I beams broke and he pulled it in half.
We had a bad snow and ice storm come through and collapsed the building and put the manufacturer out of business. he never rebuilt and the ruins of his “business” are still there today.
You would have roasted in that thing in Texas then. I lived in one for about six months right after college. My light bill was over $150 a month. This was in the late 70's when some Houstonians were paying less than that for their rent.