All good points. Thanks.

I did not mention that, in addition to the thermostats, there would be a
switch to select between
unconditionally on
auto (use the thermostats)
unconditionally off (used when unattended)
Yes the gas logs are intended for (and do a great job of) heating
There is low oxyget and CO protection.

Using a refrig thermostat would require a relay and I wonder if I could get
the necessary temp range since it crosses freezing. A refrig shouldn't go
lower than freezing and a freezer shouldn't go higher so they MAY not be
made for the desired range???

On Mon, 13 Dec 2010 15:01:46 -0800, Bob wrote:

On 12/13/2010 13:02, wrote:
I want to be able to turn on my gas logs automatically whenever an indoor
thermostat is calling for heat AND an outdoor thermostat says the
temperature is below a temperature selected from a range of 25 to 40
degrees F.

I am trying to find a low cost termostat for the outdoor portion of this
system.

For a cheap way of doing this, consider cannibalizing an old
refrigerator for a thermostat. This may require some additional control
circuitry as a typical refrigerator thermostat contact OPENS when the
temperature falls below the set point.

A few other words of caution: Are the gas logs designed for room
heating? Typically they're just for show. Are they designed for
automatic unattended operation with a pilot safety relay or automatic
ignition with no-flame cutoff? Is there a high limit switch as exists
on heating appliances? These potential dangers, as well as
self-interest protection measures from the HVAC industry, limit the
availability of these devices to the DIY hobbyist market.