University of Florida researchers have published their study of heat treatments to control bed bug infestations (free PDF). What distinguishes their approach from other published accounts is the DIY character of their method and materials: space heaters, fans, polystyrene boards, thermometers. All of $300.
As opposed to whole-room or chamber heat treatments, which necessitate expensive specialized equipment, their aim was to use heat to economically treat infested furniture by creating a heat envelope, an area within a room where, with the aid of inexpensive insulating materials, temperatures could rise to lethal levels—moderately high temperatures are sufficient—and then to use residual treatments in areas outside the envelope where heat could not penetrate. This point is important to understand and stands as my only caveat; bed bugs placed in control vials in closets or areas away from the heat definitely survived.
(It’s no secret that desperate bed bug sufferers do desperate things. Others have noted the ineffective and counterproductive measures frequently taken. Given the possibility that you might rush off to Home Depot without thinking things through, I worried about having to say many responsible things, but you can read for yourself. If you’re capable enough to pull this off on your own, good for you. If you’re not but think that you are, then no warning from me is going to deter you.)
This is the article and at the moment it’s available as a free download here.
Pereira, Roberto M.; Koehler, Philip G.; Pfiester, Margie; Walker, Wayne (2009) Lethal Effects of Heat and Use of Localized Heat Treatment for Control of Bed Bug Infestations. Journal of Economic Entomology. 102(3). 1182-1188. doi: 10.1603/029.102.0342
For the purposes of these experiments, the fact that the heat did not penetrate areas outside the envelope was judged an advantage:
Despite generating temperatures well above the lethal levels for bed bugs (41–49°C) within the treatment envelope, the heat treatment did not elevate the room temperature to temperatures >32°C (Table 3). Maintaining the room temperature at comfortable levels for human activity is very important because the heat treatment is intended to supplement a residual pesticide applied to the baseboard and other potential resting areas for bed bugs. Such treatment could be applied while the room furniture is exposed to heat treatment.
I’m not sure how much it helps to kill the bed bugs in the sofa (even if they might be the hardest to kill of all) but still have bed bugs under the window sill, but if a war of attrition is all there is against these bugs, so be it.
I appreciate the discussion of what failed and I hope those of you interested in this solution will study this closely.
The bed bugs placed in different locations during the treatments had 100% mortality for all but two trials: the first trial (room D) and the initial trial in room Yb, both in rooms with tile floors. The initial treatment trial never produced lethal temperatures for the bed bugs in any location where temperature was measured. The maximum temperature reached was 41.5°C after 6.3 h, and the total treatment period was 7.3 h, indicating that the temperature in the treatment envelope did not rise during the last hour. This stabilization of the temperature was due to the excessive heat loss through the plastic tarp and the tile floor. Once polystyrene sheathing boards were used as the insulation around the treated furniture, the heat loss was significantly reduced and temperatures continued to increase throughout the treatments.
Yet more interesting are the boundaries of what was investigated:
These results demonstrate that short exposures to temperatures above 41°C will cause temporary immobilization of bed bugs, even when lethal levels were not reached. Once the bed bugs’ exposures to high temperatures were interrupted, some insects were able to survive. We did not test long-term survival of the heat-exposed bed bugs and did not determine whether survivors’ fitness was compromised. Bed bugs that survived exposures to nonlethal temperatures have been shown to have reduced fitness (Janisch 1933, 1935, cited by Johnson 1941). Sublethal effects of high temperatures are documented for several insects (Neven 2000, Mahroof et al. 2005). However, thermal wounding by sublethal temperatures may be as deadly, but without obvious effects that lethal temperatures cause (Denlinger and Yocum 1998).
These experiments were conducted in University of Florida dorms and campus housing, a convenience that has been exploited before.
1924
In 1924, at the Agricultural and Mechanical College of Mississippi, bed bugs were successfully treated by simply turning on the dormitory building’s steam heat in the summer (average high temperatures of 115.8°F produced 100% mortality). This of course has nearly always been regarded as impractical.
The question of sublethal effects is an interesting one. In the Mississippi experiments, monitor boxes containing live bed bugs were placed in some of the rooms. Here’s an account of the fate of those bed bugs in one room:
In another room, most of the bugs were alive at 8 A. M. of the first day when the temperature had reached 108 degrees. At 1 P. M., with the temperature at 111 degrees, a few were found paralyzed; at 5 P. M., with the temperature at 114 degrees, all were apparently dead and the box was then removed. Several days later, the contents of the box was re-examined. At this time, 6 nymphs and 5 adults were dead but 3 nymphs were found to be alive, though paralyzed. Twelve days after removing from the heated room, the contents of the box were again examined and all were found to be dead, the paralyzed nymphs having failed to recover.
Dead, recovered, dead again. Nice.
Harned, R.W., Allen, H.W. (1925) Controlling Bedbugs in Steam-Heated Rooms. Journal of Economic Entomology. 18(2). 320-331.
While we’re here visiting the 20s, there’s a small joke in this article that we may as well examine for what it reveals of the polite bed bug fictions of the day (making me wonder what our own are today).
The authors describe the dormitory as one where many rooms “were found to be heavily infested with living bugs.” The paper must have been presented and a portion of the discussion transcribed with the article as there is a brief Q&A at the end:
MR. L. O. HOWARD: [...]
I have never been at the Agricultural College of Mississippi, but I had the pleasure of meeting a group of Professor Harned’s former students a year and a half ago at Gulfport at a dinner, and I saw the extraordinary love and admiration that they have for him. But it seems to me, assuming that this large dormitory could not have become naturally infested by bedbugs, that it must have been a part of a large experiment of introducing bedbugs in which the whole student body was concerned. From that point of view, it strikes me as one of the most extraordinary pieces of cooperation on record. (Laughter.)
UF’s research showcase
The University of Florida has a showcase document for their research, a bed bug manual of sorts that is well worth a look. You get to see useful pictures of the heat experiments, lots of information and recommendations on fumigation (Vikane), the armed forces’ technical guide on bed bugs included, plus a PCT article on the UF bed bug management method, Fumigation, Steam, Dusting and Labor, Walker et al. and a number of interesting slides.
If perhaps you’ve always wondered how fast bed bugs may crawl, or what exactly is meant about their missing tarsal pads, wonder no more. Here’s a link to the PDF and this is the page at the University of Florida. (The PDF is a large file, 100 pages.)
Further heat reading
There are also two 2008 PCT articles about heat trials if you wish to read further and compare notes, one from University of Kentucky researchers, Bed Bugs, Heat and Hotel Rooms, Potter et al. and another from a UC Berkeley group, Hot House, Getty et al.
Update: Doug Summers in a comment notes a safety caution:
I would like to caution anyone who is thinking about using this approach to consider using a proper commercial heater, instead of the residential style 1500 watt portable oil units that were utilized in the study.
The issue is fire safety… If you enclose the heater with insulated panels then you have voided the warranty… There was an extensive recall of this style of heater a few years ago… They were causing fires due to a faulty override switch that should switch the heater off at 130 degrees F.
These pages may be of related interest:
I really enjoyed the presentation of this study at the FPMA conference.
I would like to caution anyone who is thinking about using this approach to consider using a proper commercial heater, instead of the residential style 1500 watt portable oil units that were utilized in the study.
The issue is fire safety… If you enclose the heater with insulated panels then you have voided the warranty… There was an extensive recall of this style of heater a few years ago… They were causing fires due to a faulty override switch that should switch the heater off at 130 degrees F.
Running the heaters wide open & relying on the override switch to regulate the heat at 130 degrees F presents a serious fire risk… Particularly, if someone were to inadvertently use one of the old recalled units that were recalled for having a faulty switch.
If we use a thermal approach for the contents & treat the room with dust & residual spray products… We can achieve a fast turn around & get people back in their homes quickly.
Anyone that reads Maurice’s spam message for Bed Bug Bully… Please be advised that this is a ficticious person promoting some crap that is pure snake oil… If you give them your email address… you will get a series of spam messages overselling this dubious product… I expect that Renee will be removing the spammed ad message soon.
Thanks, Doug, for that. And for the important info re the heaters.
I really would have loved to see this presentation.
My first thought — which is the conventional one — is that people in private homes and in apartments should use professionals whenever possible, for various reasons, including obviously any possible question of liability. Heat treatment, I should have noted, is available professionally in NYC, even for individual apartments.
But a great many people and institutions are left behind by conventional advice.
My only concern is the type of heater that was used… relying on the override switch to regulate the temp is just not a good design… Bill Whitstine performed dozens of fire investigations where these heaters with the faulty thermostats had started fires before they were recalled.
A heater that is designed for these conditions would completely solve the problem.
I love the concept… low cost… use existing power supply… cheap materials & quick turn around times.
If someone decides to follow this blueprint… Please be sure to add a smoke detector & a fire extinguisher to the equipment list… Do not leave the improvised chamber unsupervised even for a couple of minutes due to the fire danger… Use temp sensors & keep the temps under 140 F… Be careful not to overload electrical circuits (which is another way to create a fire)… One heater per 15 amp electrical circuit..
This is similar to the approach being utilized in Seattle… except they are using commercial equipment as a heat source & a staff electrician to make the electrical connection directly to the power source.
One more caution… Don’t try this is a room that has a fire sprinkler head on the ceiling… Depending on the temperature that builds up in the room… a hot spot could set off the sprinkler head & cause major water damage & huge liability.
Professionals have an insulated cover that contains dry ice to keep the sprinkler head from reaching its activation temp which is usually in the 160 -220 F range, but can be as low as 135 degrees F .
Thanks, Doug. Perhaps this is more the speed of a facility manager, say, with complete control over the structure; looks like one may not need a lot of cash, but surely a team of quick-witted people not to make a royal mess of it.
This is great stuff in terms of what could potentially be done to address some aspects of the problem, but in a way there is like a reinvention of the wheel. Rentokil had a system for heating objects (I’m afraid I don’t recall the name) – which was a plastic chamber into which objects such as sofas and personal items could be placed, but the main drawback as i recall was cost to clients. I agree with Doug’s comments. There are so many pitfalls and risks if this is tried by homeowners, and potential for creating havoc — as Doug notes about triggering heat alarms – a false alarm by a fire department costs thousands of dollars and some municipalities charge for what they consider to be either malicious or inexcusable false alarms (i.e. through lack of foresight and trying something that probably should not be done in a multi-dwelling setting as a do-it-yourself undertaking, not because some people could do it successfully, but rather because the risk factor for it going wrong could be very high. I am reminded of a man who was going to doing a foundation upgrade in his home… moving the foundation a few feet by removing and replacing blocks. This proved to be fatal as the wall fell on him. Sad.. and in this case, illegal as a contractor would have got a building permit, but the homeowner thought he could avoid all that.. Expensive error in judgement for him. If there were an affordable kit for home use, that would be something, but my take on it is that this coiuld be a very useful part of a professional treatment — if it were deterimined that infestation was sufficiently widespread that this could be the key to killing bed bugs in furniture and in other items (e.g. books in open plastic crates). I think there is definitely a major role for heat treatment, but i think that this takes some reflection by the industry on how to use this tool cost-effectively. Equipment needs to be ;priced so that even small or medium sized firms coiuld afford to have a few kits for use, and then cost to clients would also be appropriately reasonable. If a firm could provide the chamber and let the client fill it appropriately, and then do the actual treatment, that might be a cost effective approach… I still, however, come back to the issue of early detection and early treatment so that the infestation is stopped before it has spread to more difficult to treat locations… We need a very high level of professionalism in this work, and it is not there yet by any means. We see overcharged services with overkill as well as superficial services. Sometimes control is the luck of the draw if it was reported early and the treatment was sufficient to eliminate the little bloodsuckers – to put it succinctly but politely.
Good stuff for sure i think,,, but i don’t believe this is a practicaL DIY project and it may never be…
Food for thought and action by industry… Some may say that use of dichlorvos could accomplish the same thing more easily… but of course, this has to be weighed in terms of airing out safely. Some dichlorvos products can be in homes in closets, and if it were possible to close off one room, and air it out properly, that would accomplish the same result.. I would prefer heat… but if dichlorvos could ber used safely, this is much more cost-effective.
I am hopeful that full heat treatment may yet be practical and cost-effective. Right now, at least for non profit housing, it is not…
Sam
Hi Sam,
But isn’t one of the problems that there are patents involved? I don’t understand the situation with respect to the major companies involved, so this may be a stupid question, but can professionals do improvised chamber treatments without infringing on these patents?
Renee
That is a very interesting question… I have looked at some of the patent information that is available on Google.
One covered a portable trailer unit that used propane (or other fuels) to heat air that is delivered through large flex ducts into the building with an electrical generator for the fans & other equipment.
A second patent covered the use of a large trailer as a chamber for heat treatment.
There is a language describing the use of a heat envelope in a building. The heat envelope appears to be formed by flexible thermal blankets in the drawings with heated air passing through the envelope that contains the items being treated.
Like any good patent… the language is very broad… I think we would need an opinion from an expert on patent law to interpret whether the UF approach is an infringement on the existing applications.
Thermal treatment has a long history in commercial food storage & other applications. Note the use of steam heat in dormitories in the 20s… I am not sure that the concept isn’t already in the public domain…
I would imagine that there are limits on staking a claim for the rights on tactics that have been utilized for over a century
Honestly I don’t know anything about it except that it was something I remember, an offhand remark in a conversation with someone. It’s always imprudent to talk about things one does not understand! So I’ll stop. :/
I agree with Doug, Renee…. there is really little in the way of patentable information in these systems. A hearter is a heater. A plastic containment chamber is what it is.
I know that the equipment developed by some firms such as Harris in partnership with Chromalox are being sold as a package for about $60,000 which is pretty expensive for a small operator. There are other systems also available, but again,, these are sophisticated and not inexpensive.
These systems are designed for heating a hotel suite or an apartment,but the cost is in the range of about $2,000 or more and the time to prepare and treat is extensive.. usually about 6 hours. The beauty of this is that when it works it is 100% effective, but in a multi-dwelling setting, it is quite difficult to do and there is fear of escape. Stephen Kells has done some detailed work on this that should be published soon… There are critical factors such as ensuring that core temperatures are reached. The use of the chamber was also quite costly. There is also the prospect of actually heating an entire building, as the temperatures are relatively low in terms of heat — sort of like a summer’s day in Cairo or Rhiyad or Phoenix almost.
the method has promise I think, but I just don’t see this as a practical DIY project for the vast majority of people. It may find certain applications as it is better understood and developed.
Sam