So if it has a temperature control, that’s how it would work. It senses when it’s too warm and shuts down… then when it cools, it kicks back on.
If you put the stone in a really chilly place, it might stay on all the time (since the stone stays cool, the heater stays on to try to warm it up). If you have it in a nice warm room, it’ll probably get “warm enough” and click on and off as needed.
It’s your glowforge, I would suggest “trust but verify”… if you have a way to check the temperature inside the GF, I would do that for the first little while to see if the stone is doing what you need.
I have been looking for solutions for being able to keep my GF out in our workshop without leaving our heating on 24/7 (our electric bill has doubled).
We have had many subzero temp days this year and I put so much work keeping GF warm. I made it an insulation cover, + and an insulation blanket + a sleeping bag. It was not enough. After reading these forums, I purchased the thin reptile mat (10 by 20). That seemed to be too warm (temp would get to 80 degrees) … did not think this was good if the rest of the shop was 30 to 40. Got a smaller one and temp inside GF was a nice 60 degrees. Problem with that is it is one of the adhesive mats. Then got the rock after seeing your post and inside GF is 50 while workshop is 30. This seems to be ok but as I mentioned some of the time the rock is cool so I was not sure if it is malfunctioning or not.
I keep a controlled seed starter in my unit. But the basement itself is often 40F-45F. So even though the inside of the unit stays in the usable range I still must heat the space for about an hour before I go down to use it. Don’t want 45F air being pumped into the unit. It would shut down once the inside cooled.
Oh yes. I do the same. I actually bring shop temp up to 70 or so before using. But I was finding I was needing to heat shop up on everyday even when I was not using just to keep GF warm. Got quite expensive!