I've got 6 gallons of ale fermenting in an insulated chamber. One scavenged TEC unit from a coleman power-chill cooler. Also hooked up an Analog Johnson control in the vain hope that it would be needed.
First results are not very encouraging. Only able to keep temps in the mid to upper 60's and getting the temps down takes hours. I was hoping to get the chamber down into the 50's as a gauge of performance or benchmark. No such luck.
More insulation probably would help a bit. And, as it stands the temps for fermentation have been adequate so it isn't a failure. What was hoped for- was a wider temp range to play with that could be controlled by the thermostat.
Pros: Whisper quiet. Small footprint, utilizes existing equipment. Keeps fermenter at mid to upper ale temps.
Cons: Not efficient- poor chilling capacity. Drips condensation from chill-sink. Temps swings with ambient temp. Expensive.