Bed bugs, small reddish-brown insects that feed on human blood, are a persistent household pest worldwide. Their presence often raises questions about their resilience, particularly concerning their ability to survive in cold environments. While adaptable, their cold tolerance has specific temperature and duration limits. Understanding how bed bugs react to varying temperatures is important for both prevention and control.
How Bed Bugs Handle Cold
Bed bugs can endure cold, though they don’t thrive in it. One adaptation is their ability to enter a dormant state (diapause) when temperatures drop. This state involves a significant reduction in their metabolic rate, enabling them to conserve energy and survive for extended periods without feeding. During this dormancy, their development can be halted at temperatures below 50°F (10°C).
They are “freeze-intolerant,” meaning their body fluids freeze at certain low temperatures, leading to death. The mean supercooling point, the temperature at which their body fluids freeze, ranges from approximately -21.3°C to -30.3°C (-6.3°F to -22.5°F) across all life stages. This means they lack antifreeze-like compounds that would prevent internal ice formation.
Freezing Temperatures and Bed Bug Mortality
Killing bed bugs with cold requires specific, sustained low temperatures; brief exposures are insufficient. Research indicates bed bugs are less susceptible to freezing than once thought, with eggs, nymphs, and adults showing varying tolerance. For 100% mortality across all life stages, including resilient eggs, temperatures must be consistently low for a considerable duration.
Studies have shown that a minimum exposure time of 85 hours (approximately 3.5 days) at -15°C (5°F) is required to achieve complete mortality of all life stages. At even colder temperatures, such as below -20°C (-4°F), the required exposure time decreases to 48 hours (2 days). Therefore, effective eradication requires maintaining the freezing point long enough to overcome their cold endurance.
Using Cold for Bed Bug Control
Applying cold for bed bug control can be an effective non-chemical method for certain items. For successful treatment, infested items should be placed in sealed plastic bags to prevent escape and moisture damage. These bagged items need to be subjected to 0°F (-18°C) or lower for at least three to four days. It is important to use a thermometer to verify that the freezer consistently maintains this temperature, as many home freezers may not reach or sustain temperatures cold enough, or may fluctuate with frequent opening.
Simply lowering a home’s thermostat during cold weather is not an effective whole-house solution for bed bug infestations. Temperatures inside walls, furniture, and other insulated hiding spots often remain warm enough for bed bugs to survive, or they can enter a dormant state. For larger infestations or items that cannot fit into a home freezer, professional cryo-treatment may be an option. This method uses specialized equipment to apply ultra-cold carbon dioxide snow, freezing bed bugs on contact and killing all life stages.
Bed Bugs Outdoors
Bed bugs are primarily indoor pests, preferring stable, warm human dwellings. They are not found thriving outdoors, especially in cold climates, as they seek consistent temperatures and blood meals. Established outdoor populations are rare because fluctuating, often severe outdoor temperatures, particularly in winter, are not conducive to their long-term survival and reproduction.
While bed bugs do not live outdoors, they can survive for limited periods on infested items left outside, such as furniture or luggage. They might hitchhike on these items and be inadvertently brought indoors. However, relying on outdoor cold to eradicate bed bugs from infested items is unreliable due to inconsistent temperatures and their ability to find temporary shelter.