You want to kill bed bugs fast with a DIY method to cut treatment costs. One popular method of getting rid of bed bugs is extremely cold temperatures. If freezing kills bed bugs and eggs, you could put the infested items in the freezer or leave them outside during winter months.
Bed bugs die at temperatures lower than 3 degrees Fahrenheit. Some studies suggest that they die in one hour at 3 degrees; others say it takes several days. Either way, you can freeze bed bugs in the freezer or by leaving them outside. However, this method isn’t foolproof.
Bed bugs (Cimex Lectularius) have become more common in the past decade. That’s why scientists are exploring better ways to eliminate them. Below is everything you need to know about freezing bed bugs, from why freezing hurts them to what temperature will kill them.
Table of Contents:
Is Freezing Bed Bugs Backed by Scientific Evidence?
Bed bugs are vulnerable to harsh temperature changes. They don’t like it when it gets too cold, or too hot. If it gets cold enough, then they can die, like any other insect or animal.
A paper in the Journal of Economic Entomology called ‘Cold Tolerance of Bed Bugs and Practical Recommendations for Control’ looks at how cool temperatures affect bed bugs.
The author, Joelle F. Olson, tested bed bugs at various stages of their lives. Bed bugs go through five life stages (instars) before reaching adulthood. Olson wanted to find out whether young bed bugs freeze more quickly than older bed bugs.
What she found was that bed bugs are freeze tolerant, but only to an extent. Some insects can resist low temperatures through a process known as supercooling.
This is where their bodies reach temperatures that would typically freeze them solid, but they use physical and chemical tactics to remain unfrozen.
However, bed bugs don’t do this as well as other insects. That’s why they’re so susceptible to cold.
At What Temperature Do Bed Bugs Die?
Olson found that bed bugs die at temperatures lower than 3 degrees. However, it took 80 hours on average for the temperature to finally kill them. This is a lot longer than other studies suggested.
At lower temperatures, the length it takes for them to die becomes shorter. Olson stated that at temperatures lower than -4 degrees Fahrenheit, it took just two days to kill a bed bug.
Other studies, such as one was published in the journal Medical and Veterinary Entomology, have different results. That study found that bed bugs die in just one hour at 4 degrees. Olson also referenced other studies which reported similar findings.
The reason for these discrepancies isn’t clear. The difference could be due to the kind of blood used. The two sources she referenced used rabbit and chicken blood, while Olson’s used human blood. Bed bugs prefer human blood, and perhaps the nutritional difference in food sources had an effect.
Olson also theorizes that the difference may have been because of cooling rate. While each study reached similar temperatures, her method of cooling the bed bugs took longer to cool them down. This more accurately reflected the experience of a bed bug in a freezer like you have at home.
Do Bed Bugs Like Cold Rooms?
Bed bugs can survive just fine in cold rooms. Unless you lack a heating system, it will never get cold enough in your home to kill bed bugs. It takes temperatures at which you might die to work.
But you don’t have to lower the temperature to something that could kill them. Just by lowering the overall temperature, you can make them bite less often. Here’s why:
- In cold temperatures, it takes bed bugs longer to digest their food.
- Because it takes them longer to digest, they feed far less frequently.
- Because they feed less frequently, they grow more slowly.
- Because they grow more slowly, they lay fewer eggs.
A difference of just a few degrees can mean that your infestation becomes less severe. In the cold, it can take them a week or more between feedings. This could give you some much-needed relief.
You could try turning the thermostat down, or using more sheets and blankets on your bed. You could also wear pajamas. This will have a double effect, since the bed bugs will find it harder to access your skin. Bed bugs can’t bite from fabric, such as bed sheets and pajamas.
How Can Bed Bugs Survive the Winter?
Insects have three ways of surviving cold winter weather:
- Migration. Many insects migrate in the same way that birds do. When it gets too cold, they fly in a straight line away from where they live to find somewhere warmer.
- Freeze tolerance. This means that the insect allows their body to become frozen. The insect prevents damage to their body tissues through a variety of means, both chemical and physical.
- Freeze-intolerant. This is where the insect prevents their body tissue from freezing. To do so, they lower the freezing point of their body fluids, almost like they’re using antifreeze. Being freeze-intolerant is also known as supercooling.
Why Do Bed Bugs Die in the Cold?
Bed bugs don’t migrate, because they don’t like going outdoors. They’re freeze-intolerant. This means that they lower their body temperature without allowing themselves to freeze. They can remain unfrozen as low as -6 to -22 degrees Fahrenheit.
This is the temperature at which they freeze solid, despite their best efforts. But the fact that they’re freeze-intolerant doesn’t matter. They still die at low temperatures anyway.
Bed bugs become inactive at around fifty degrees Fahrenheit. They stop scuttling around, they stop feeding, they stop mating, and they stop laying eggs. They find an enclosed space in which to hide, and wait until it’s warmer.
Bed bugs are susceptible to temperatures far above their supercooling point. Any temperature below 8 degrees could be lethal, so long as it’s maintained for long enough.
Do Bed Bugs Bite During Winter?
While bed bugs are less active in colder temperatures, that doesn’t mean they don’t bite during winter. They live indoors. People have the thermostat set higher during the winter to keep warm.
Being indoors during winter, bed bugs keep warm enough to continue feeding, mating and laying eggs. If you were to lower the thermostat, then they would slow down, but not stop biting.
It’s only when you put them outside that the bed bugs might start to suffer. Depending on where you live, the temperature might dip far enough to kill them over winter.
Can Bed Bugs Survive Outside in Winter?
If you live in Florida, the winters won’t get cold enough to kill your infestation. However, if you live in the far north, then it may get cold enough to kill them.
The study above showed that if bed bugs are exposed to temperatures of 3 degrees or less, then eventually die. If the winters are unusually cold, then leaving them outside may kill them.
However, there are issues with this approach:
- You have to keep the bed bugs in bags. Inside the bag or box you keep them in, it won’t be as cold as the air outside.
- The temperature has to be stable at 3 degrees or below to kill the bed bugs. If the temperature rises above the figure before they die, then they can carry on living just as they were. They will even feed again when they get the chance.
- If the bags aren’t properly sealed, then the bed bugs will get out. They’ll search for somewhere warm, and get back inside your house. Then you will have spread your infestation throughout your home for no good reason.
- Your belongings may be damaged by the cold. Valuable electronics could freeze or get wet, or your clothes could get damp and moldy.
Leaving things outside during winter isn’t the best approach. But if you can’t afford an exterminator, leaving furniture outdoors during winter might be a good idea. Wrap it in plastic so that the elements don’t damage it.
Do Bed Bug Eggs Die in the Cold?
Bed bug eggs die in the cold just like adults do. Eggs and nymphs (young bed bugs) are slightly less resistant to the cold than adults are.
There are a few reasons why that might be the case:
- Adults are capable of moving around to try and find somewhere less cold/hot. Bed bug eggs can’t do that.
- Eggs and nymphs are far smaller than adults. While insects don’t produce body heat, their larger size may prevent them from cooling down as fast.
- Bed bugs use chemicals to lower the freezing temperature of their bodily fluids. Adults have fed, and consequently, have more nutrients in their body to draw from. They, therefore, might be able to cool themselves more effectively.
If you were to freeze your things and kill every bed bug, that’s good. But if several eggs didn’t die, the infestation will start again.
Killing Bed Bugs in a Freezer
The time it takes to kill bed bugs in a freezer depends on the temperature. If the temperature in your freezer is 3 degrees or less, then you could theoretically kill bed bugs in there.
How to Kill Bed Bugs in a Freezer
To kill bed bugs in a freezer, bag the infested item and seal the bag before placing it inside. There are two reasons you should bag your items:
- It prevents frost damage. Leaving delicate things in the freezer for days can cause them to warp and crack. Bagging them helps protect them.
- It stops the bed bugs from trying to escape. The last thing you want is bed bugs in your freezer food.
There’s not much else you have to do. Just leave the package in your freezer for as long as it takes.
If possible, identify the parts of your freezer that get the coldest. It’s likely that the coldest parts of your freezer will be against the sides. Putting things here helps them freeze.
How Long Does It Take to Kill Bed Bugs in a Freezer?
Olson suggests leaving the items in the freezer at a temperature of precisely 0 degrees Fahrenheit. This is lower than necessary.
The lower the temperature, the quicker they’ll die. At 0 degrees they’ll die in a minimum of 3.5 days.
To check whether freezing your items has worked, take the bag out of the freezer after 3.5 days. Take the bag outside and empty it. Shake your items (if applicable) and see if any bed bugs come out. If they’re dead, they won’t be moving. Squash them anyway to make sure.
Don’t take things out of your freezer until the 3.5 days are up. If you do, you stand the chance of accidentally letting some out. If you seal the bag or box properly, then this shouldn’t be a problem.
What Are the Disadvantages of Freezing Bed Bugs in the Freezer?
Here are some reasons not to freeze bed bugs in the freezer:
- When faced with temperature extremes, the bed bugs will try and escape. They’ll try to hide in any gap or crack they can find. This means they could get into your food.
- You shouldn’t allow bed bugs anywhere near food preparation or storage surfaces. They feed on blood, so if you squash them by accident, you could cover these surfaces in blood.
- Freezing takes time. Three and a half days is a long time, especially because you have to treat your things one by one.
- If you have a small freezer, you’ll hardly be able to fit anything in there. If you want to put anything extra inside, you’ll have to take your food out. That’s three and a half days without your freezer, or more if you have many items to freeze.
- Many items can’t be frozen, such as sensitive electronic equipment. Look into whether your items can be safely frozen before you attempt to do so.
Freezing Bed Bugs with CO2
Freezing bed bugs with CO2 isn’t a new idea. It’s a method that some pest controllers use. It isn’t anywhere near as widespread as pesticides or heat treatment, however.
The industry leader, Cryonite, manufacture a kit that can be purchased online. It costs several thousand dollars, which is perhaps why it’s not widely used. It’s a simple kit that comes with a tank on wheels and a long applicator with a trigger.
There are several upsides to using supercool CO2 to kill bed bugs. It’s entirely safe, since no pesticides or harmful chemicals are involved. It’s also environmentally friendly, since the carbon dioxide that’s used is typically recycled.
Can You Kill Bed Bugs with CO2?
If you want to kill bed bugs with dry ice, the idea isn’t to freeze them to death. The point is to starve them of oxygen. According to the Journal of Medical Entomology, bed bugs are susceptible to CO2 concentrations of 30% over 8 hours.
There’s a specific approach required for killing bed bugs with dry ice. Take a plastic box with a lid that seals shut. Place the items you want to fumigate inside, and leave the dry ice in there with them. Then, leave the box for at least a day, preferably longer. Experiment to see what works.
However, there are a few drawbacks to using CO2 to kill bed bugs.
- You can’t gauge the CO2 levels without specialist equipment.
- Dry ice is harder to source than most other pest control materials.
- CO2 doesn’t work on bed bug eggs unless it’s at 100% concentration.
Hot vs. Cold Temperatures to Kill Bed Bugs
It’s far better to use heat to kill bed bugs than cold temperatures. It’s easier to reach temperatures too hot for bed bugs.
Reaching temperatures that are too cold for bed bugs isn’t possible with AC. But hot temperatures are attainable with powerful heaters.
Another reason why you should consider using heat instead of cold is speed. When you raise the temperature to 122 degrees, or higher, bed bugs die within minutes. This is much faster than putting them in the freezer, which takes days.
There are also certain items that should be heated rather than frozen. It makes much more sense to wash and dry clothes at lethal temperatures rather than freezing them. You could freeze a shirt, but there’s no reason not just to wash it.