Temperature difference thermostat which can be used to control heating. When the inside temperature is a few degrees warmer than outside temperature, the inside humidity is kept below 70%. This prevents mold growth and other problems caused by high humidity. Also the insulation of the building or vehicle will stay dry because when inside of the vapor barrier is warmer, dewpoint is not formed inside the insulation.

With the temperature difference based control, you can keep your garage, RV or caravan in good shape during long storage, and with minimal possible electricity consumption.

Configurable difference, hysteresis and temperature limits. For the lower limit there are two options. 'Antifreeze' prevents inside temperature dropping below that value. 'Heater off' shuts down heating completely when outside temperature is below that value. If you don't have any water pipes etc. which could freeze, you can set the heating go off in sub-zero temperatures. Absolute air humidity is low in cold temperatures, and also mold doesn't grow in temperatures below 0 degrees Celsius.

You can find more information of the project, PCB design files, compiled firmware and source code on the project web page at http://kair.us/projects/temp_controller/index.html (sorry, currently only in Finnish!)