2019.10.10: Thermostat Woes

I got my new gas heater installed and it works with an external thermostat (instead of my ventless gas heater which has an internal thermostat and a knob at the top that you can make it warmer or cooler). This is cool except I’m finding out that most thermostats have a lowpass filter and only expect the temperature to fluctuate so quickly and no more. I first tried a Honeywell bi-metal completely mechanical thermostat (CT50K1028) which when I set it, has 10 degree swings:

Honeywell mechanical thermostat suffers from 10 degree swings (ignore light purple, that’s an adjacent room). 

I then tried a programable thermostat, the White Rogers 1F81-261 which came as our main house thermostat and we subsequently replaced with a wi-fi thermostat. I was hopeful a digital thermostat would have a much better response time, but when I set it to 70 F, the greenhouse hit 85 F before the thermostat registered 70 F and kicked off! That’s pretty bad! I read the manual and it doesn’t seem like there is a way to adjust that aside from setting a fast cycle and slow cycle (but I was already on the fast cycle).

I then found that I could adjust the thermostat anticipator on Honeywell mechanical thermostat and set it to the shortest setting and still saw a 10 degree swing, so that’s disappointing. While I expect this problem to become less as winter approaches because it will take longer and longer to reach the desired temperature as it gets colder and colder, I will have to continue to investigate to see if there are some better ways.