Subtitle: killing the little b@#$%^&s
Attention: the FAQ below was written before the invention of a tool which many readers will find useful. The Packtite allows people to easily use heat to remove bed bugs from items which can’t go in a washer or dryer on hot, such as unwashable clothing, books, papers, shoes, etc. You can read more in the Packtite FAQ.
This FAQ started out with the title: “Heat and bed bugs: 5 minutes in a dryer– really? Say it’s so!” The first part outlines my reaction to a brief article, and the second answers many of my questions with a more detailed article. I realize this is kind of roundabout, but I did not want to delete the original post entirely.
I started out by considering a fascinating brief article in PCT Online (Dec 2006) that rounds up information provided by bed bug researchers in a panel at the 2006 National Pest Management Association Conference. What’s interesting is that the researchers cover a wide variety of topics (from the efficacy of various pesticides to the usefulness (or not) of vacuuming, steaming, and hot dryers.
Personally, I was intrigued by University of Kentucky entomologist Michael Potter’s assertion that a normal machine wash would kill bed bugs (“normal” as in, not hot ?), and five minutes in a hot dryer would kill bed bugs and eggs. I said I’d like to see more data on this–I did not doubt it at all, but is it really so? Since a wash won’t kill eggs, this must be why the hot wash / hot dry combo are always recommended in university fact sheets. We’re told the dryer is what kills the eggs. But I think I’ve only seen Dr. Potter being quoted as saying five minutes drying was enough.
A hot dryer apparently runs at about 180 F. I doubt this temperature is achieved after five minutes, though. Can five minutes on a temperature somewhere below 194 F be enough, when companies providing thermal treatments do so at a core temperature of 140 F for four hours? (Winston clarifies this in the comments.)
But this is the only source I’ve seen on “five minutes being enough” (though it has been quoted in newspaper articles). Personally, habit and skepticism have had me recommending drying for over an hour. I always say, “dry on hot till it’s bone dry, then add 20 minutes.”
But then, dear Reader, I confess, I dotted my bed with lavender oil for months, hoping its reputed repellent properties would keep bed bugs away. I figured it probably wouldn’t, and it didn’t. But it was hard to give up this habit, since I believed it might be helping. That is kind of irrational, but I guess that’s what sleeping 4 hours a night does for you.
Since washing and drying and storing clothing properly can make such a difference to bed bug treatment, I emphasized that we want to be sure we’re doing it right. It would be such a blessing for people to only have to dry things on hot for five minutes. It would save not only time, but lots of clothing items that simply can’t handle washing on hot and drying for an hour on hot. For those reasons, I hoped we could get more information on the research that was done.
So then, I remembered one motto here at Bedbugger Ask, and ye shall receive. (Information, people, only ask for information. If you need $500, it ain’t gonna happen.)
And lo and behold, Hopelessnomo pointed me to more information that is available from Dr. Michael Potter (and colleagues), in the PCT article “Killing them softly: battling bed bugs in sensitive accounts” (1/19/2007):
Bed bugs often infest bedding, clothing and other personal belongings which cannot be treated with insecticides. An oft-mentioned way to de-bug such items is laundering — yet to our knowledge, no testing has been done to verify effectiveness. A simple experiment was conducted to study this question. Three groups of live bed bug adults, nymphs and eggs were placed in small nylon mesh pouches which were then placed inside cotton socks. The bed bug-provisioned socks (along with a full load of clothing) were then run through a standard wash cycle using hot water. A second trial was run with similarly infested socks placed only in a clothes dryer. The bed bug-laden socks were accompanied by a load of unwashed clothing and subjected to high heat (greater than 175° F) for five minutes. No bed bugs or eggs survived the washing or drying cycles, suggesting that either regimen, alone or in combination, is effective.
Clothing, footwear, area rugs, toys, stuffed animals, backpacks and other non-launderable items can conveniently be de-infested by heating them for a period of time in a dryer at most settings. For reference, a typical clothes dryer run for five minutes at low, medium or high heat produced temperatures of about 140, 150 and 180°F, respectively, amongst a bundle of dry clothing– plenty hot to kill bed bugs. While certain items may require professional dry-cleaning, utilizing conventional washers and dryers may help limit the spread of bed bugs to these establishments.
This information suggests that either a hot machine wash, or a hot dryer running for five minutes with already dry clothing, will kill bed bugs and eggs. As Nomo suggests in the comments below (written before I added this update) “five minutes with dry items” is not so different from what we’ve been recommending at Bedbugger all along: “bone dry plus 20 minutes.” Well, make that “bone dry plus five.” I don’t blame if you if, like me, you’re a bit skeptical and want to stick to “twenty minutes past dry”– we won’t call you neurotic.
As John sang, “Whatever gets you through the night, it’s alright, it’s alright.” For Bedbuggers, that’s another motto around here. The promise of a good night’s sleep is the grail.
As of 2012, there’s a new product which will help determine if the required temperatures are reached for heat treatment. Although a hot dryer should be running very much higher than 120F as noted above, if you have any doubts about the machine you’re using, and want to be sure your dryer hits 120F, you can use Thermaspot temperature sensors (made by Packtite) to test this. Just attach them to the inside of one or more items, and run them through the dryer. If the dryer hits 120F, the sensor will turn from white to black. Read more about Thermaspot here.
The rest of the information from the January article is also more detailed and informative than the summary from December. Let me give you the highlights from what Dr. Potter et. al. recommend:
Discarding infested stuff: yes, but only if necessary. Seek a qualified PCO’s advice (qualified = knows the enemy well). If you are tossing it, wrap it well (and mark it!) and realize that if your neighbors or surrounding community pick up the item, they may come back via a crack in your shared wall, a visit to a dry cleaner’s, or the local diner. That should make anyone think twice and thrice.
Encasement: use high quality encasings that won’t tear.
Vacuums: harder to pick up bed bugs and eggs than you think; doesn’t really help unless you hit their harborage areas in a targeted way. Discard bags carefully (bed bugs can survive the trip down the hose), and do not use vacuum brushes, since they can lodge in the bristles. The dirty little so-and-so’s.
The steam portion of this FAQ has now been incorporated into the new FAQ on steam:
How to kill bed bugs with steam. It’s relevant both to treating your home and furniture and steamable “stuff” too.
Seasonal temperatures (“putting stuff outside”)
Regarding seasonal temperatures, backpackers take note: We get a lot of questions at Bedbugger about whether “leaving stuff outside” works–and occasionally hear from people who tried it and failed. I think it comes down to the temperature, the length of time, and what you provided the bed bugs to nestle in. (The last complaint I heard was someone whose down comforter had bed bugs surviving the cold — well, perhaps it was a very warm down comforter, and maybe it just was not cold enough outside to freeze them within it.) Dr. Potter says, in “Killing them softly”:
Lethal outdoor temperatures have long been employed in the battle against bed bugs. In the tropics, infested bedding is often left out in the sun and such methods can also be used during warm seasons in this country. It’s risky, however, to rely on ambient heating to achieve lethal temperatures in all harborage locations. Wrapping items in plastic before placing them outdoors in a sunny location (preferably on pavement), produces higher internal temperatures. It also pays not to over pack — more trash bags with fewer items make it harder for bed bugs to find cooler places to hide. Monitoring with a thermometer is also prudent, with a target internal temperature of at least 120° F.
In colder climates, freezing might be a way to de-infest furniture and other belongings. Bed bugs and their eggs can be killed by very low temperatures, but it is difficult to achieve them without using a deep freezer. Temperatures below 0°F for one to two weeks are generally believed to be needed to reliably kill all life stages. Fluctuating winter temperatures which often extend above this level are probably less effective and are currently being studied by Dr. Steven Kells at the University of Minnesota. Overall and throughout much of the country, heating tends to be a faster, more reliable option than chilling.
Again, if you experiment with ambient heat (which we do not recommend), at least consider using Thermaspot heat sensors (FAQ) to ensure required temperatures were reached at the core of the items.
Thanks to Dr. Potter and his team for their helpful research on how to get rid of bed bugs using heat.
And special thanks to Hopelessnomo, who mentioned the article in the forums, and directed me to further sources.
Additional information on thermal, cold, steam, etc. is included in Stephen L. Doggett’s Bed Bug Code of practice. See the table of contents.
Frank, at the War on Bed Bugs, also did an interesting post on hot and cold treatments. Check it out.
Some people have recommended something like this for drying shoes in the dryer:
If you are thinking of using a dry cleaner for some or all of your clothing, read this FAQ first!
NotSoSnug points us to a library protocol for getting bugs out of books:
I should add that there is a librarian protocol to heat paperwork at 130degF for 3hrs to kill insects (remember to include a pan of water to keep some humidity). Any longer will melt binding glue (I know I forgot one night and it did). Also, till tape receipts are heat sensitive so they will turn dark. Annoying if you need the receipts for business!
See the ‘Bookworm’ section, Paragraph #7:
For clothing which will be washed, you have the option of packing laundry in GreenClean bags. They allow you to seal in dirty laundry, and wash the items directly in the bag, which will dissolve in the laundry process. They provide an alternative to using and throwing away garbage bags.
Click here to find out more or to purchase Green Clean dissolvable laundry bags (sealed bag goes right in the washing machine).
Last updated 11/25/2012