With bed bug heat treatment we constantly see advances in programs and training that help the industry.
Most of this is provided by the experts that make it their mission to study bed bug behavior and determine the best means of eradication with the least amount of impact to the general population.
Lately, though we have seen the introduction of small heaters that run off of 120 V circuits that are being used to heat hotel rooms and small apartment areas to eliminate bed bugs. Thety have also been implemented in heating larger areas as well usually being left in place to heat areas over a 24 hour period. This is not only unsafe but I believe will only spread issues to other parts of the hotel or building in which the treatment is taking place.
The thermal death point of bed bugs is 117° Fahrenheit. Studies show that 100% of all eggs will be rendered nonviable at 130°F if held for 10 minutes at that temperature. (Thank you Stephen Kells.) In most cases, electric heaters are brought in that are generator fed so that temperature rise can be steady and usually lethal temperatures can be accomplished within 1 to 2 hours.
Newest equipment being marketed is fan based heaters which plug into multiple circuits and are left in place for 24 hours or longer until the heat treatment is completed. These units are usually used in smaller areas of 300 to 400 ft.². What is common that even with the smaller areas 4 to 8 circuits are typically required. Unfortunately, in many buildings, the electrical requirements are not there to sustain the amount of heaters to bring the temperature up to levels lethal to bed bugs at a uniform or fast enough rate.
Seeing firsthand the activity of bed bugs in response to heat this causes some concern as the new methods may not be helping eradicate bed bugs but may in fact, be spreading bed bugs to other units. We have seen this with bed bugs fogging or bombing whereas one unit is treated with a total release aerosol and the insects that are not killed flee to all surrounding units. Typically what we see is an initial response once we get over 100°F of insects emerging from areas that they are harboring. Upon emergence, we see a probing behavior where the insects are testing the areas that they are on to see if it is something that they can feed upon. In many cases we actually see bed bugs moving towards the source of heat being provided to treat the apartment.
Once we get closer to the thermal death point of bed bugs we see a change in behavior. In certain cases, this involves the bed bug attempting to dig deeper into its harborage area or it will start to move away from the heat source looking for an area of lower temperature. With traditional heating methods where you can maintain a good and steady temperature rise of 15 to 30 degrees per hour this is usually not an issue. Before the bed bug population can flee the area they have already been exterminated. With equipment that is providing a temperature rise of only several degrees in an hour the allotment of time that allows for escape is much too great.
Time will tell whether or not this new method (Small Fan based Heaters) is a good addition to what traditional thermal remediation companies are doing. But in many instances, these packages are being sold to management companies as well as hotels and motels that have little pest control experience. In addition, most pest application laws require a licensed individual to apply perimeter pesticides which would in this case help prevent the escape of these insects into adjoining areas. Overall though the main issue with these heating systems is the slow heat rise.
Based on my experience with thermal remediation tactics over the last 11 years I believe we will see a worsening of the issue, an increase in spread patterns in both hotels and buildings that attempt to do this on their own, and a detraction to the reputation of thermal remediation practices which have been, up until this point, when performed by professionals, stellar.