This document is not final and is subject to change.
When bed bugs first returned as a pest in the United States, the use of cold temperatures and freezing were explored as treatments. However, unlike the immediately lethal effects of heat and steam, freezing requires sustained exposure at very low temperatures to affect bed bugs. Some researchers suggest that freezing is inconsistently effective and may not kill all bed bugs all of the time. For this reason, freezing is not a reliable option for getting bed bugs out of personal items.
Professional freeze treatments through the application of liquid carbon dioxide or liquid nitrogen are available and appropriate for some situations. However, research on container (freezer) freezing has shown that sustained temperatures of 0°F, the temperature of most household freezers, are needed for 4 or more days to kill all stages of bed bugs and their eggs. While lower temperatures will kill faster (two days at -4°F; immediately lethal at -6 to -22.5°F), these temperatures are not practical for most situations, and higher temperatures are not guaranteed to work. For example, a well-known scientist pulled a container of bed bugs out of a household freezer that had been frozen for five years. One of the bed bugs recovered and became active after 5 years!
Interestingly, research has shown that the feeding status of bed bugs does not affect their ability to survive the cold. In other words, bed bugs that had recently eaten were just as susceptible to freezing as those that were starved. This has also been observed with pesticides, although bed bugs that are able to feed after pesticide exposure had an improved survival rate.
A challenge in freezing is that current conditions may influence an insect’s ability to survive. For instance, if the ambient temperature is already low, freezing is less likely to be effective. Furthermore, bed bugs are capable of rapid cold hardening, such that exposure to cold temperatures (one hour at 32°F) increases the ability of bed bugs to survive at 6.8°F and 3.2°F.
The bottom line: We do not recommend freezing in a household freezer to treat items for bed bugs. It is not guaranteed to work. Professional freeze treatments are available for certain situations.
Advantages and Disadvantages:
- Advantages:
- Professional treatments that use liquid carbon dioxide or liquid nitrogen can often be used on surfaces that would be damaged by high heat, including toys, plastics, and books.
- Carbon dioxide snow produces less moisture compared to steam, which might make this applicable for items such as electronics.
- Disadvantages:
- Unlike steam and heat, cold treatments that rely on liquid carbon dioxide or liquid nitrogen do not penetrate into pleats and seams of mattresses. Therefore, this treatment technique necessitates direct contact with the target insects.
- The velocity of ‘snow’ from liquid carbon dioxide/nitrogen treatments is capable of blowing bed bugs off of the substrate before a lethal exposure to the cold temperature.
- Anecdotal evidence suggests that some bed bugs are able to recover from cold treatments, and that even direct contact with freezing temperatures may not be sufficient to kill the insects, but rather immobilizes them.
- Like other similar treatments, the use of liquid carbon dioxide/nitrogen is time consuming because all cracks and crevices must be treated.
References for Freezing Items to Kill Bed Bugs:
- Benoit, JB, G Lopez-Martinez, NM Teets, SA Phillips, & DL Denlinger. 2009. Responses of the bed bug, Cimex lectularius, to temperature extremes and dehydration: levels of tolerance, rapid cold hardening and expression of heat shock proteins. Medical and Veterinary Entomology 23: 418-425.
- Benoit, JB. 2011. Stress tolerance of bed bugs: a review of factors that cause trauma to Cimex lectularius and C. hemipterus. Insects 2: 151-172.
- Choe, D-H, & K Campbell. 2014. Effect of feeding status on mortality response of adult bed bugs (Hemiptera: Cimicidae) to some insecticide products. Journal of Economic Entomology 107(3): 1206-1215.
- How, Y-F, & C-Y Lee. 2010. Effects of temperature and humidity on the survival and water loss of Cimex hemipterus (Hemiptera: Cimicidae). Journal of Medical Entomology 47(6): 987-995.