According to DerbyDad03 :
On Oct 31, 9:34 pm, (Chris Lewis) wrote:

Over thirty years ago, we found that some thermostats start
at around 50F with an offswitch, and others don't have an
offswitch, and start around 36F.

We wanted the 36F ones to keep a cottage just above freezing.

In reading some of the questions that get sent to the Home Repair
section of our local newspaper, I think I recall something about
issues with condensation if the temperature is kept below some magic
number (50?).

This sort of thing is going to be very dependent on conditions.
Not just environmental, but building structure and ventilation.
As a simple example: our garage.

It's vapor-barriered (6 mil plastic) and insulated with decent attic
ventilation. When we moved in, the floor was just gravel. Unheated.
Approximately two days per year (usually in the fall), there was a
moisture problem that caused bare metal (eg: my tools) to begin to rust.
Visible condensation everywhere.

A few years later, we had a concrete floor put in with a layer of foam
board under it. Moisture/rust problems _completely_ disappeared. There
are now heaters in it, and I only turn them on when I'm going to be
working in the garage for extended periods during the winter. When the
heaters are off, the temperature in the garage can drop as low as -30C
or lower during the winter. Zero moisture problems (except when
the ceiling vapor barrier fatigued in a few places and fell through,
and the attic got too warm - icicles and condensation at the
ruptures.)

The cottage is similarly well insulated and vapor barriered (kraft
insulation). We heated the cottage itself to 4-5C. At first there
was a moisture issue _under_ the cottage - concrete block foundation,
dirt floor, and we also kept the pump area warmer by enclosing the
section with a double "curtain" of 6 mil plastic and a fan heater
modified to operate at around 5C. But that was eliminated by
power venting the crawl space outside of the "bagged" zone.

The only moisture deterioration problems were in the cottage ceiling due
to "cathedral ceiling" (2x6 Cedar T&G, 1" foam, sheathing then shingle -
no ventilation), no sunlight due to trees (roof stayed damp) and
(eventually) carpenter ants. Everything was torn off but the T&G,
"joists" were laid over the T&G, bat insulation with a 2" airgap
under the sheathing. Moisture problems eliminated.

Anyone saying "don't go lower than 50F" or something like that will
be doing a CYA because they don't know whether it really will cause
a problem or not. Whether it causes a problem is determined by
the building and weather conditions.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.