We use an old refrigerator with a thermostat control.  The refrigerator has good insulation.  The thermostat control is a chicken incubator unit that is available over the counter here in Australia.  We run the incubator at 35 degrees centigrade with a pan of water in the bottom for keeping the humidity high.

We use two 40W light bulbs in the bottom for the heat source.  We use rigid construction bulbs as they do not blow like normal bulbs.  They blow because of the bulbs being switched on and off by the thermostat.  We use two bulbs in case one breaks.  We originally thought of a bar heater but reasoned that overrun of temperature on the heating cycle would be too great.  There is no overrun with the light bulbs.

Originally we had a small computer fan for air circulation but when it burned out we found that convection currents were just as efficient and did not break down.

We have been using our unit for 12 years now.

Trevor Weatherhead
AUSTRALIA

www.superiorbee.com.au