Millivolt programable heat only thermostat?

[Rothrock42]

My greenhouse has a gas furnace and thermostat that works on a millivolt system, that is they don't require mains electricity and will continue to function even if the power goes out.

But since the thermostat is millivolt, it doesn't have the ability to run a schedule of "a bit warmer during the day and a bit cooler at night" It only has one set point.

I was thinking that there might be a battery powered millivolt thermostat out there where the battery runs the clock for different day/night time settings. But I'm having a hard time finding that and most of them seem to be non-programmable.

So here is what I'm looking for and wondering if anybody has experience and can recommend a reliable thermostat.

• Only heat. I don't need extra inputs for fan or AC; that just complicates things.

• Doesn't require connection to mains electricity, i.e., millivolt compatible

• Able to set a schedule like 10:00a to 4:00p minimum 70 and 4:00p to 10:00a minimum 60.

• At least somewhat moisture resistant since it will be in the greenhouse.

Thanks for any advice or suggestions.