I was asked to heat sterilize a load of televisions, computers, and computer desks. To minimize damage to these sensitive items I ensured the maximum temperature coming into the chamber was limited to 143f. The return temperature after 13 hours was 141f. These temperatures will easily kill bed bugs in these items because there is little insulation to inhibit heat transfer. The interesting thing i noted was that a colony of cockroaches was sequestered into an imperfection in the computer desk. When I opened the door I found 5 adult cockroaches and numerous immature cockroaches on the desk top dead and dehydrated. I do not know the science on killing cockroaches with heat but it appears that 141f will kill cockroaches. Interesting.
Update October 6, 2014
I heated another load of furniture for bedbugs at 140f for 12 hours – more than adequate for bed bugs. When I delivered the furniture I noticed many dead cockroaches as well. Interestingly I also noticed a single immature cockroach on the exterior wall of the trailer walking around seemingly unharmed. It appears that 140f for 12 hours kills many of the roaches but there is a risk of failure. From now on I will not recommend low temperatures (140f) which is useful for killing bed bugs in electronics to also kill cockroaches. It appears that I should use 150f if cockroaches are included in the load. This means that I can not reliably get roaches out of electronics as they are limited to 140f by UL rules.
My trailer is 7 foot by 12 foot and is insulated with 3 inches of spray foam insulation (R21). the fan moves 3000 cubic feet per minute (an average furnace for a single family home moves 1500cfm) ensuring the trailer is very windy and cool spots are minimized. The heater uses a full 50 amps at 220v. All told this trailer functions like a Ferrari – it is a ridiculously powerful heating machine that ensures cool spots are minimized. The trailer was not at fault for failing to kill the single live roach I observed – it was the temperature setting.