Does Freezing or Heat Kill Silverfish?

If you're dealing with silverfish and looking for a natural way to get rid of them, you might be wondering: does temperature make a difference? Can extreme cold or heat kill silverfish? The short answer is yes, but how you use it matters. We'll explore how silverfish respond to temperature extremes, how to safely apply these methods, and when they work best.

How Silverfish React to Temperature

Silverfish are cold-blooded insects, which means they rely on the environment to regulate their body temperature. They prefer temperatures between 20°C and 27°C (68°F to 80°F) and thrive in warm, humid conditions.

That makes them vulnerable to both extreme heat and extreme cold - if those temperatures last long enough.

Can Freezing Kill Silverfish?

Yes, freezing can kill silverfish, but it needs to be cold enough and last long enough to be effective.

• Temperatures below -17°C (1°F) can kill silverfish if sustained for several hours
• This method works well for infested items like books, boxes, or fabrics
• Place items in sealed plastic bags and freeze them for at least 3–5 days

Freezing is especially useful for delicate or valuable items that you don’t want to treat with sprays or chemicals.

Tips for Using Freezing to Kill Silverfish

• Use a deep freezer or chest freezer for more consistent temperatures
• Seal items in plastic bags to prevent moisture buildup and condensation
• After freezing, inspect items for damage and vacuum away any eggs or debris

Keep in mind: freezing won’t prevent future infestations. You’ll still need to clean and seal areas where silverfish may return.

Can Heat Kill Silverfish?

Yes, heat can be an effective silverfish killer. Silverfish can’t survive in environments above 45°C (113°F) for long.

• Using a dryer: Heat-treat clothing, linens, or small fabric items on high for 30–60 minutes
• Steam cleaning: A steam cleaner can kill silverfish and their eggs in carpets and cracks
• Direct sunlight: Placing items in full sun for several hours may also help

Be cautious when using heat on delicate or valuable items, and always follow product care instructions.

Can You Heat or Freeze a Whole Room?

Whole-room or whole-house treatments do exist, but they are typically done by professional pest control companies. These methods involve:

• Sealing off the space and using specialized heating or freezing equipment
• Monitoring temperatures carefully to ensure they reach lethal levels
• Holding that temperature long enough to kill silverfish and their eggs

This approach is effective but expensive and usually only used in extreme cases.

When These Methods Work Best

Heat and freezing work best when:

• You’re dealing with small, contained infestations
• You want to treat stored items without chemicals
• You combine them with cleaning, sealing, and long-term prevention

Think of freezing and heat as part of a full strategy, not the only solution.

What They Don't Do

• They don’t eliminate silverfish hiding in walls, under floors, or deep in insulation
• They won’t stop new silverfish from entering your home
• They may not kill eggs unless temperatures stay consistent for long enough

For best results, combine heat or freezing with vacuuming, traps, and sealing entry points.

Yes, both freezing and heat can kill silverfish, but they’re most effective when used on individual items or as part of a larger pest control strategy. If you’re dealing with silverfish in books, clothes, or storage boxes, a few days in the freezer or a high-heat cycle in the dryer might be just what you need.

And remember: controlling moisture and removing silverfish food sources is the real key to keeping them out for good.