Coldframe Ventilation

I know I said yesterday I'd talk about my ideas for heating and ventilation for the coldframe I'm building. My laptop computer is in the process of dying and I spent most of the evening backing up files. I'm really lucky that my kids gave me a 5GB Seagate pocket drive for Christmas. The backing up process hasn't been too bad but I'm tired and decided to just write about my ideas on ventilation tonight and save heating for tomorrow.
One problem I've had with coldframes in the past is having the temperature get too hot inside. It may be cold and cloudy in the morning when I go off to work or somewhere else. Around noon the sun may come out and if I'm not home to prop open the cover of the coldframe the temperature inside can get too hot and cook the plants inside. Last year I did some research and for a little under $40 I bought an automatic window opener made for greenhouses. With some combination of springs and melting wax (I think) this device will open a window when it gets hot and close it when it gets cold. According to the directions the opening temperatures are adjustable between 59F - 77F.
Now the part I'm not sure about is should I have it open the cover of the coldframe which would be the traditional way or should I install it on the cellar window that will actually be inside the leanto coldframe so the cellar window will open when it's too hot in the coldframe. This would allow the waste heat to go into the cellar. One problem with the second idea is that I was possibly planning on opening the cellar window as an emergency heat source into the cold frame on very cold nights. I'm leaning toward the first idea of using the automatic opener on the coldframe cover and not the cellar window, but would really welcome any ideas anyone has.