Larry Weil wrote:

I have an older house that was originally a summer house, but was later
converted to year-round use, located in North Salem, NH.

A few years ago I had six inches of blown-in fiberglass added to the
attic, on top of what insulation was already there. This helped a bit,
especially in the summer, but in the winter the temperature is still
quite uneven, and in real cold weather it is impossible to be
comfortable no matter how high I turn the heat. The heat is oil fired
forced hot air. Underneath the house in an uninsulated (but blocked
off) crawl space that is less than a foot deep, so it would be
impossible for anyone to go in there to insulate the floor.

I had an insulation contractor in today for an estimate on insulating
the walls. The walls have vinyl siding, and the only insulation is the
foam board under the siding. A couple of years ago I had the bathtub
replaced, and when it was out I could see the sheathing with no
insulation on the inside.

This contractor proposes blown-in fiberglass insulation. I asked him
about potential problems from the fiberglass settling, and he said what
they do is a two hole system, where that make holes and blow in
fiberglass from both the top and bottom of the wall, and that will
compact it enough that it won¹t settle enough to be a problem.

My question is if this is really a good way to go, if the two hole
system really works to prevent the insulation from settling and forming
a gap at the top? Has anyone here had that done and has it worked?

BTW, I called three insulation contractors, and the one that came was
the only one of the three that bothered to return my call. Why do these
guys bother to advertise if they¹re not going to return your call?

--
Larry Weil
Lake Wobegone, NH

I'd suggest that depending on the construction details it may not be all
that difficult to either excavate the crawl space out to say 24" where
it is workable, and / or to lift the entire house to the same effect.

For the blown in fiberglass in the walls, I believe there is a version
with a slightly sticky binder included that helps lock things in place
once it's blown in.

A good starting point for everything however is a simple blower door
test and / or thermal IR camera survey to identify air leaks and the
worst insulated spots so you can triage and prioritize your actions.

Don't underestimate the value of servicing the furnace and having the
registers balanced. It is also possible to zone the heating system.