How to Minimize Moisture in Your Safe | Northwest Safe

How to Minimize Moisture in Your Safe


Do you see rust on your guns or metallic items in your safe? Does your safe smell musty and moldy? Is mold visible on your safe’s interior fabric or paperwork? 

We encounter a lot of safe owners who buy their safe, fill it up, and think their job is done. Reality is, protecting the environment inside is just as important as keeping thieves. 

What is the Danger of Moisture in my Gun Safe

In addition to just smelling funky, moisture in your gun safe can cause irreparable and even dangerous damage to its contents. Guns are one of the biggest concerns when we encounter moisture damage. 

A safe protects your guns against fire, misuse, and theft. But it doesn’t protect it against humidity. Exposing guns to moisture can lead to rust, causing parts to stick together and the firearms to potentially misfire. This is why, in addition to cleaning and thoroughly drying your guns before storing them, we strongly recommend keeping your safe’s dewpoint at a low level.

Rusty gun in safe

What’s the Dewpoint Inside My Safe?

The dewpoint in your safe is based on the temperature and humidity inside the safe. This dewpoint determines your risk level for a harsh moisture environment.

The quickest way to measure those two parameters is with a Hygrometer/Thermometer gauge, such as the Eva Dry EDH-85. This allows you to use a dew point calculator to evaluate your risk levels. This is my go-to dewpoint calculator: (And as an added bonus, it’s free!) 

Example of a Healthy Safe Dewpoint

The safe in my garage right now has a temperature of 55 degrees and a humidity level of 46%. Using these numbers, the dewpoint calculator determined my dewpoint is “34”. Furthermore, all my environmental ratings are in the “GOOD” or “OK” range, as seen in the chart below.

How to Minimize Moisture in Your Safe

Due to the wet climate in the Seattle and Portland area, there can be high humidity in the air. This means gun safe owners need to take precautions to keep moisture from invading their safe. The best practice is to run two dehumidifiers, giving you a backup.

In my 50 size gun safe, I use an 18” long GunSaver dehumidifier rod and an H2out SD303 rechargeable desiccant device.

If I was going to only run one device, it would be the 18” Dehumidifier rod. They only draw 12 watts of power, are UL listed, require zero maintenance, and cover up to 200 cu ft of area.

dehumidifier rod

Gun Safe Dehumidifier Rod

Dehumidifier rods are warm to the touch. This creates constant air movement inside the safe as the warm air rising to the top. This movement of air is what keeps moisture from forming on surfaces inside the safe. 

H2out SD303 Rechargeable Desiccant Device

A desiccant device is filled with desiccant crystals that absorbs moisture. Some desiccant devices are one-time-use. I like to use the H2out SD303 Rechargeable Desiccant Device for a variety of reasons, including:

The Recharge Time is Short: Once the crystals change color, I can bake it in the oven at 300 degrees for 2 hours to remove the moisture and make it good as new. 

They Have an Incredible Track Record: NW Safe first started carrying this brand in the late 80s. Since then they’ve sold thousands a year. We’ve never seen one start a fire or melt an item it has come into contact with. 

They are Rugged: Thanks to its stainless body, it can survive being dropped or thrown on the floor. 

They are Environmentally-Friendly: Because you don’t have to toss this one out like a disposable device, it means spending less money and less waste! 

4 Additional Ways to Reduce Moisture

  • Dry Rice
  • Baking Soda
  • DampRid
  • Moth Balls

loaded safe

Why Run 2 Dehumidifier Devices? 

As a general rule of thumb, the more valuable the contents of your safe, the more you’ll invest in protecting them. Running two dehumidifiers might seem overkill, but it allows you to prepare for the worst. 

In addition to the two dehumidifiers listed above, there are other good units on the market. Depending on your needs and lifestyle, you might like a different dehumidifier better. For instance, you may need a dehumidifier with a bigger capacity, like the EVA DRY 365 or the EVA DRY 500. 

What Do I Do if There is Moisture in My Gun Safe?

If you discover there is moisture in your gun safe, remove all items that might be affected — especially firearms and metallic items. Then, place a dehumidifier and/or a desiccant device inside. If these don’t lower the moisture levels within a few days, call a professional safe technician to help you diagnose the issue and develop a plan to protect your safe’s environment.   

Get Professional Help

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