How hot, how long, how dead?(13 posts)
How long does it take to kill bed bugs, at all stages, with heat?
From the University of Florida, slide #11 of the PowerPoint below:
100 minutes at 106F
25 minutes at 109F
4 minutes at 113F
2 minutes at 117F
1 minute at 120F
Remember that this is the temperature you need to get the bug (or egg) up to for the requisite time. So, 1 minute in a 120F dryer is likely not sufficient, you need to get every last bit of your stuff up to the desired temperature. When the thermal people bake a house, they need to run their process long enough to penetrate every last cubic inch of the home (including deep in the couch and inside the walls.)
If you less heat available, or have items that can't take high heat, you can still kill, if you give it more time.
From a practical point of view -- one strategy is to take the temperature reading in the middle of whatever it is you're heating, and then hold the temperature at 120 degrees for an hour. At least this is the formula recommended by the developer and manufacturer of PackTite. Heating similar items makes this a lot easier. If you're going to do a mixed-batch -- for examples shirts and books -- then you might want to use two thermometers (or at least two readings) to test the temperature for both of the dissimilar items and then make sure the formula is kept. Another formula often given is to put dry clothes into a dryer on the "hot" setting and then let it run for around 20 minutes. Assuming your dryer gets up to around 170 degrees (you can test this with a thermometer) that should be ample time and temp to kill any bed bugs as long as the dryer isn't stuffed. Of course you can always double-check the temp of the clothes with an instant-read thermometer.
Richard, not directed toward you (no conflict with anything you added), but I get the impression that these times and temperatures ended up getting "stretched" in translation by people on this board and beyond. So "hold the packite at 120F for an hour" (which makes sense) becomes "well, you need to bake a BUG at 120F for an hour to kill it, but my dryer won't penetrate every bit of my item, so I'll run it on high for 2-3-4 hours, etc.". So, I felt that posting the "starting point" would be helpful for a lot of discussions.
Cileto: So "hold the packite at 120F for an hour" (which makes sense) becomes "well, you need to bake a BUG at 120F for an hour to kill it, but my dryer won't penetrate every bit of my item, so I'll run it on high for 2-3-4 hours, etc.". So, I felt that posting the "starting point" would be helpful for a lot of discussions.
Just to be clear, I also found what you posted helpful The more information the better. And nothing like a thermometer to at least initially keep things honest be it the dryer or PackTite. And like you suggest, the dryer isn't a PackTite, especially if you use the dryer rack as for example with shoes. Stuff on the dryer rack will take longer than things bouncing around in the dryer because there is less air circulation. PackTite solved that problem by incorporating a fan into the unit. I just used two common examples because this has become a confusing topic since it's actually not as cut and dry (unintentional pun) as it may seem on face value.
Richard, how do we use a thermometer to test the temperature inside a dryer? I would think the probe cord on the thermometer that comes with packtite would get all mangled in a rotating dryer. Is there some kind of special thermometer for testing in a dryer?
Your question is a good one. The only way I was able to measure the temperature in my dryer was to place a remote read out thermometer probe on the shelf. What I found was that my Frigidaire dryer did not even get close to 170F. It seems to have some kind osfsafety shut off, so that temperature reading would be140 and then the temperature would drop until it reached 129 and then start climbing again.
The way I tested it was I opened the dryer in the middle of the cycle and inserted an insta-read thermometer into the centre of the pile. The clothes registered at about 115-120 fahrenheit for that snapshot (the dryers in my building are somewhat elderly, but are clearly sufficient for destroying the DOOM bugs).
I used a Gemini data logger burried among the clothes and recorded every minute throughout the cycle. I was using some really big, old tumbledriers and found that they did the job but it took about 15 mins to get up to 106oF and it didn't get much above 109oF over the 30 min cycle.
109, huh? I have worried that the dryer I use is not so hot, since I know my landlord would use an economy temperature cycle. So I almost always washed as well, hoping that they might drown if it isn't really hot enough (the water is sure hot--why doesn't heat from water kill them?) When I gauge that temperature and possibly find out that it didn't get so hot in the dryer, I wonder what I will think then, about the past 2 months of endless laundering. Oh, well, no one that I see has complained about anything, so just have to keep my fingers crossed. Packtite sure gets more than hot enough, so I feel safe for the future, if not the past. That packtite is the most valuable thing I own at this point
> the water is sure hot--why doesn't heat from water kill them
It does, if it's hot enough, thorough enough, long enough. Unfortunately, in many washers, some items are floating at the top rather than fully immersed. There's nothing keeping the water hot once it emters the tub. And the hot wash cycle is 10 minutes or less, followed by spin and cold rinse. IIRC, water and detergent will kill many bugs and the washer's action will likely flush many down the drain, but stragglers and eggs could still be a problem.
Just a thought about the Packtite. It´s a tool in the american market right ? As I understand it most stuff sold there they exaggerate some stuff, advice etc, not to blamed, drawn into court/law by customers. Also the same exaggerationpatterns can be seen a little off when it comes to bedbug-advice.
Wouldn´t it be likely that a company then producing a bedbugkilling oven adds a littel extra to the times needed ? Not that I think it´s bad...better safe than sorry with bedbugs.
Just saying that the packtite-rules should maybe not be taken as a natural law or rule for what´s correct. New research should always be considered as well, but used with caution I guess.
What temperature will get bugs to flee to a cooler location, in situations where they can?
I'm wondering whether you can disinfest a piece of furniture by warming it to a temperature that's not lethal but will get the bugs to leave. And maybe kill them on the way out, by having it on a sheet of plastic with some stuff for them to hide in, then sealing up the plastic and throwing it away when you're done.
If you watch our "packtite kills bed bugs video" on YouTube you will see that the bed bugs start freaking out at around 110 f. I would assume that somewhere in that area they begin to become uncomfortable. However, recent studies have shown that when bed bugs are exposed to heat by convection (fan forced like packtite), instead of trying to escape they tend to briefly leave then retreat back to their harborage spot and die there. If the heat is done by conduction (surfaces heated and heat gradually transfers by direct contact to a heated surface), the bed bugs will move away from the heat source. So for your sofa example, conduction would work much better to make them leave an area, like a heating pad or radiant heater with no fan.
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