We know that bed bugs die at 122f within 1 minute (actually the eggs hatch and the first instars then die when exposed to this temperature). We also know that to achieve 122f in the middle of a dense item that one must increase the temperature to about 142f as an average temperature to get the heat into the middle of that dense object. And that leaves no room for error. Electric whole home heat treaters get around this problem by aiming their 150f maximum outputs (CSA/UL limited) directly at dense objects to get a good kill. Dense items that do not receive 142f for a couple of hours have a real risk of not attaining a core temperature of 122f.
We also know that if you pack many items together with no air flow between pieces the likelihood of attaining 122f core temperatures is small. Heat sterilizing furniture is like baking a turkey – it takes time to get the inside cooked and the bigger the item the slower it heats. Piling items together simply makes a bigger and more difficult single item to heat.
We also know that the container that contains the furniture loses heat depending on insulation levels and the outside temperature. The warmer it is outside and the better the insulation levels the more heat is available for cooking the contents. For example, if you input 150f into an entire home in winter you are lucky to get 130f average temperatures. 130F is not adequate to penetrate dense items as 130 minus 20f for heat transfer equals 110f. Bed bugs die at 122f. If the container is super insulated and it is hot outside the average temperature will be much higher.
We also know that it is hard to distribute heat perfectly evenly. For example how do you get heat into the item in the far corner of the room – especially if it is sitting on the floor. You may have ideal temperatures in the middle of your treatment room. What is the temperature on the edges and corners?
We also know that some fuel based heat treaters use temperatures up to 185f inputs which I have found reliably damages furniture. Actually anything over 165f inputs is asking for trouble. And we also know that most electronics have a maximum long term storage temperature of 140f. If you are inputing 150f – 185f (in the hope of attaining 142f average temps) it is possible that the electronics may be directly in the path of the hottest incoming air and be damaged.
Therefore the following questions should be asked of your heat sterilizer:
- What input temperature will you be using and what will be the average temperature (this number will change depending on outside temps and type of container)? How long will you be maintaining the temperatures to ensure that a minimum of 122f is imparted to the middle of dense objects? How many hours will it take until the container has achieved a killing temperature.
- How do you ensure that the heat is evenly distributed? How do you ensure that all items receive the correct amount of heat to achieve a kill? How do you organize the furniture to ensure everything is correctly heated? By the way if temperature sensors are used in the load they are only as good as where they are placed. If the employee wants to go home early he/she will move them to less dense objects directly in the hot air stream.
- How do you protect electronics from temperatures over 140f. Anything heated beyond its CSA/UL rating loses its CSA/UL rating.
- If you are heating couches and electronics in the same load (in a trailer) how do you kill the bugs in the couch without exceeding the 140f maximum rating for the electronics? This is an excellent question. Watch for straight out lies, squirming, and shifty eyes as that is quite a feat.
- How do you get heat into the items resting on the floor? The cool floor prevents heat from entering the item on the floor.
- Is the heat contractor willing to take the furniture into his/her own home when treatment is complete? If not how much longer should the treatment take before the contractor is willing to move the furniture into his/her own home?
If the contractor can not answer these questions it is time to look elsewhere.