The writers of the questions and the authors of the answers are a
little more specific regarding location - Western NY - where temps and
humidity can vary greatly due to lake effects.
IIRC 50 seemed to be the recommended number - perhaps a generic
number, albeit for a different reason than you suggest. In other
words, not generic so as to cover a national audience, but generic
enough to cover the wide swings of weather conditions near the lakes.
In any case, the OP might want to do a little research and determine
if "just above freezing" is the correct temperature for his location.
I contend it is the same reason. :)
I'd even wager they would give the same answer for any geographic area
outside the High Plains or Desert Southwest (and would be highly like to
there as well because they probably have no experience in any other
climate so would still use the CYA answer).
Another consideration is a safety factor. A building at 50 degrees will stay
above freezing longer in a power failure than one at 32.1111 degrees. Not a
big deal if comfort is the only consideration, but if keeping water from
doing damage, you have to plan ahead a bit.
I maintain a large (poorly insulated) building that is used for storage, but
cannot freeze. Keeping it at 45 is good for at least 30 hours.
Don't let my kids see this post! They'll want me to turn up the
thermostat in the winter using the "we'll stay above freezing longer
in a power failure" excuse.
Shut up kid and go get another sweater. ;-)
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
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.
Age and Treachery will Triumph over Youth and Skill
If you have some way to calibrate it, it may be possible to tilt one of the
mercury switch thermostats enough to lower its operating point adequately.
It may be possible to alter the internal spring mount to accomplish the same
Some RV thermostats have no OFF position but I so not know what the minimum
I live in Canada where it would be usual to have this application. The garage
that I want to heat to just above freezing is attached to the house, well
insulated so a heater with a thermostat that can be set from about 0 degrees C
to 10 degrees C or more would fit the bill. My question is - why do
manufacturers not provide this option, and why can I not find ANY heater that
gives the minimum and maximum temperature setting of the thermostat on the box?
I have a ceiling mounted electric heater with fan. Not sure of the
exact thermostat range as it's unmarked except for little dots and an
off position. I keep at "just on" over the winter and it keeps my
insulated shop at about 40 degrees. When I want to spend time out there
working, I just pop in, turn it up a bit and within 15 minutes or less I
can work in my shirtsleeves. At a rate of ~ $0.1035 per kWh the affect
on my monthly electric bill is negligible.
If you can't find one looking through Grainger, et al, let me know and
I'll pull the model number and make for you.
Alternatively, I suspect that it might not be all that difficult to find
a line voltage thermostat that would operate in the range you want/need.
Just wire it into the circuit and leave the thermostat on the heater
set to your preferred "working temperature". Crank up the external line
voltage stat when you want to work out there, turn it back down when you
just want to keep it from freezing.
It's called a thermocube thermostat. It turns on the heater at 35F
and turns it off at 45F. It is available from Home Despot in the USA.
It is apparently a Canadian invention .
Contact Christy Fabros
Public Relations Specialist
Nuheat Industries Ltd.
firstname.lastname@example.org for information on where to buy one close to you.
On Tuesday, November 10, 2015 at 10:37:11 PM UTC-5, email@example.com wrote:
HD sells the plug-in thermocube. Before relying on one, I'd suggest
reading online reviews. When I looked into them, I saw a lot of people
saying they were unreliable, would work for a few months, then when it
should go on, didn't and stuff froze.
I agree with the poster that you would think there would be more
quality choices available for that kind of thing, but I couldn't
find any other choices either when I was looking.
On Wed, 11 Nov 2015 04:31:00 -0800 (PST), trader_4
I've used those Thermocubes for livestock tank heaters, to prevent them
from staying on when the air temperature rises above freezing. They are
not very reliable. I wont buy them again.
They do sell thermostatically controlled fan switches, made for large
barn fans, which are intended to turn on the fan when the barn temp
rises above a set temp, such as 70deg. They are 120V switches. But I
dont think they go down to freezing temps. I believe they make similar
things for heating controls. Check out www.grainger.com
They sell a lot of that type of thing.
The OP could make a control if they are handy. Mount a relay in a
suitable electrical box. The relay contacts must be at least 15A. (20A
is better). Put a plug on cord and an outlet on this box. The plug goes
to a wall outlet, the outlet feeds the heater. Then mount a 24V
transformer on the box, and run wires to a plain thermostat (not
programmable). The relay must have a 24V trigger coil, the wires from
the thermostat feed that relay trigger coil.
It's hard to explain without a wiring diagram, but it's a simple
circuit. A thermostat is really just a switch that is controlled by
temperature. It's just switching the relay to the ON position when the
temperature falls below a certain temp, such as 40deg. The relay
contacts are 120V and they turn the heater on and off.
I built something similar once, but in my case the relay turned my
furnace on and off, based on a sensor on a woodburner. When the
woodburner got above a certain temp, the furnace was turned off. The
reason for this was because both shared the same ductwork. If both the
furnace and woodburner fans ran at the same time, the big blower in the
furnace would overpower the small fan on the woodburner, and cause it to
self destruct. This relay insured that both blowers did not run at the
same time. Relays are very useful for lots of things.
On Wednesday, November 11, 2015 at 7:32:55 AM UTC-5, trader_4 wrote:
The description at the on-line Honeywell store says:
"It's important to note that this unit will not work with
line voltage systems, multi stage systems or heat pumps
with or without auxiliary heat."
However, I would think that any number of low-voltage-line
voltage relay would work, no?
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.