Well, I think that there is no difference, I have a Bi-metal thermostat in my modified THI10 Brower Top Hatch incubator. I also have a wafer in my mini fridge. They both hold temp within a degree or less.
I have been busy building incubators for friends and I was looking for a way to bring cost and weight down. The bimetals are half the cost of wafers but I wasn't sure of accuracy. Thanks for the reassurance. I've brought down weight by using 1/4" plywood insulated on the inside with foil type insulation (works great) and brings down weight and cost
Can anyone tell me can a bi-metal thermostat fail? How does it compare to a wafer thermostat? Should I use a wafer or bi-metal on my large incubator? I want something reliable that won't cook my eggs if it fails.