Why 7-day freezing is the best solution when you don't know what kind of bug it is
Many people have experienced the same situation: you see a small insect at home or while traveling, but you don’t know what it is. Is it a bedbug , a clothes moth , a fur beetle , or some other household pest? The fact is, most people don’t know for sure what insect species they are – and they don’t need to. The good news is that one treatment works for almost everything : seven days at temperatures below −20 °C.
In this article, we explain why 7-day freezing is the safest and most scientifically sound solution when you're not sure of the species of insect – and why it brings you real peace of mind (Canadian Conservation Institute, 2019; National Park Service, 2021).
Why exactly 7 days?
Freezing works in three ways:
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Freezing breaks down the cells , causing the insect to die quickly.
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Prolonged exposure to cold prevents the recovery of vital functions.
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Cooling the entire object ensures that eggs and hidden individuals are also destroyed (Canadian Conservation Institute, 2019).
Studies and conservation guidelines recommend at least one week below −20 °C , as this guarantees a perfect result even when you do not know exactly what species it is (National Park Service, 2021).
Three or four days can sometimes be enough for small insects – but a week removes the uncertainty completely . If you want to be sure that everything is destroyed, seven days is a safe, science-based choice.
Different insects have different tolerances to cold – that's why a week is the safest
Not all insects die at the same rate. For example:
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Bed bugs (Cimex lectularius) die within 48 hours at −20 °C, but if the freezer is not efficient enough or the load is large, a few more days will ensure the result (Olson et al., 2013).
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The larvae and eggs of the tsetse fly (Tineola bisselliella) are more resistant to cold, and a minimum of 72 hours of effective freezing is recommended – but 7 days also ensures the death of the eggs (Maine/Cornell, 2010).
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Fur beetle (Anthrenus spp.) eggs are particularly hardy; they may survive short periods of frost, but a week at −20 °C kills all developmental stages (MuseumPests, 2019).
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Silverfish and sugar maggots (Lepisma, Ctenolepisma) survive in dry and cool conditions, but not for a week at −20 °C (Canadian Conservation Institute, 2019).
So even if bedbugs die faster, 7 days covers all the most common pests in homes and suitcases – even those that cannot be identified visually.
Suitcases, clothes and belongings – hidden places that cannot be seen
Travel is the most common way for insects to enter homes today. The seams of suitcases, clothing and even electronic devices can harbor insects that can survive for a long time without food (City of Helsinki, 2025). A home freezer is not always the solution – it can heat up momentarily, and the insides of objects do not have time to cool down. Therefore, a professional service, such as Pakastus.fi offers a reliable solution: industrial-level freezing keeps the temperature constant and documented throughout the week.
7-day freezing = peace of mind
Many of our customers say that the 7-day treatment brings peace of mind above all else . When the species is unclear, there is no need to guess or watch at night – you can just know that the problem has been eliminated for sure.
Why 7 days is a measure of peace of mind:
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covers all stages of development – adults, larvae and eggs
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ensures cooling even in thick textiles
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removes uncertainty if the species is unknown
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works without chemicals and odors
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is completely safe for goods and people
In short: if you're in doubt, 7 days of cold will kill everything .
Why choose Pakastus.fi?
Pakastus.fi is a Finnish specialist service that offers industrial-scale freezing treatment for the control of bedbugs, clothes worms, fur beetles and other pests.
Our service differs from a home freezer in that:
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we use a constant temperature of −25 °C ,
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we monitor temperature and humidity constantly,
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we ensure complete cooling ,
You can safely bring us your suitcases, textiles, shoes, furniture and other items – we will take care of the rest.
Book a freezing service today: www.pakastus.fi
Sources
Canadian Conservation Institute (2019). Controlling Insect Pests with Low Temperature (CCI Notes 3/3). Ottawa: Government of Canada.
City of Helsinki (2025). Bedbugs travel with tourists – this is how you can protect yourself from infection. Updated 8.1.2025.
Maine Department of Agriculture, Conservation and Forestry/Cornell Cooperative Extension (2010).
Clothes moths. MuseumPests (2019). Furniture Carpet Beetle (Anthrenus flavipes) – Fact Sheet.
National Park Service (2021). Museum Handbook, Part I – Chapter 5: Biological Infestations. Washington, DC: US Department of the Interior.
Olson, JF, Eaton, M., Kells, SA, Morin, V. & Wang, C. (2013). 'Cold Tolerance of bed bugs and practical recommendations for control', Journal of Economic Entomology , 106(6), 2433–2441.