How to Keep Moisture Out of Your Gun Safe

How to Keep Moisture Out of Your Gun Safe

Many new home or gun safe owners don’t think about the need to control the humidity inside of a safe. After all, it’s just a secure box for your guns, right? Why would you need to worry about moisture? Well, most of the US population lives in areas with above 50% average humidity. If your home or apartment’s climate-control system helps dry the air, that’s all well and good. But many don’t.

Statewide averages of relative humidity and dew point for each state

A ranking (1=most, 50=least) is also included. [Chart Courtesty of Forbes]

State Average RH RH Rank Average Dew Point Dew Point Rank
Alaska 77.1% 1 26.5°F 50
Alabama 71.6% 12 54.0°F 5
Arkansas 70.9% 20 50.7°F 9
Arizona 38.5% 49 32.5°F 42
California 61.0% 43 44.2°F 18
Colorado 54.1% 46 28.8°F 46
Connecticut 69.2% 31 40.7°F 27
Delaware 70.9% 21 45.8°F 15
Florida 74.5% 2 62.7°F 2
Georgia 71.1% 17 53.4°F 7
Hawaii 73.3% 5 65.2°F 1
Iowa 72.4% 6 39.8°F 29
Idaho 62.4% 42 30.9°F 43
Illinois 70.9% 18 42.7°F 22
Indiana 72.0% 8 43.0°F 20
Kansas 65.7% 39 43.6°F 19
Kentucky 70.3% 26 46.6°F 14
Louisiana 74.0% 3 58.3°F 3
Massachusetts 71.1% 16 39.9°F 28
Maryland 68.8% 33 45.2°F 17
Maine 71.7% 10 34.4°F 39
Michigan 72.1% 7 38.0°F 33
Minnesota 70.4% 25 33.9°F 40
Missouri 69.2% 30 45.4°F 16
Mississippi 73.6% 4 55.6°F 4
Montana 60.4% 44 29.7°F 45
North Carolina 70.6% 23 50.4°F 10
North Dakota 70.9% 19 32.6°F 41
Nebraska 65.8% 38 37.9°F 34
New Hampshire 70.4% 24 36.2°F 36
New Jersey 68.5% 36 42.4°F 23
New Mexico 45.9% 48 30.8°F 44
Nevada 38.3% 50 27.5°F 48
New York 70.7% 22 39.4°F 31
Ohio 71.5% 13 42.0°F 24
Oklahoma 64.0% 41 46.8°F 13
Oregon 68.6% 35 39.0°F 32
Pennsylvania 69.6% 28 40.9°F 26
Rhode Island 71.4% 15 41.6°F 25
South Carolina 69.1% 32 51.6°F 8
South Dakota 66.4% 37 34.6°F 38
Tennessee 69.4% 29 48.4°F 11
Texas 64.9% 40 53.6°F 6
Utah 51.7% 47 28.6°F 47
Virginia 68.7% 34 47.3°F 12
Vermont 71.7% 9 35.9°F 37
Washington 71.4% 14 39.7°F 30
Wisconsin 71.6% 11 37.1°F 35
West Virginia 69.7% 27 42.8°F 21
Wyoming 57.1% 45 26.9°F 49

Additionally, temperature changes, weather patterns, or low air circulation in the safe can contribute to humid conditions. As we explain in our article about the proper care and storage of firearms, maintaining an appropriate level of humidity inside your safe (not too humid and not too dry) is one of the main factors that help prevent damage from rust, corrosion, mildew, and mold that can destroy your firearms, valuables, documents, and records.

There are several ways to keep humidity levels appropriately low inside a gun safe, so let’s go over the main options so you can make an informed decision that’s right for you and your situation.

What humidity level is best inside a gun safe?

Before discussing dehumidifiers and desiccants, let’s review the proper humidity level that should be maintained inside a home gun safe. For preventing humidity-related damage to firearms during storage, the NRA recommends keeping the humidity in your vault room or gun safe between 30% and 50% and the temperature around 60-70 degrees Fahrenheit if possible. Librarians/archivists and photography storage experts generally agree that for ideal long-term document and photo storage, humidity should not be lower than around 20-25%, shouldn’t exceed 50%, and they often recommend even cooler temperatures around 50 degrees F. This is usually not reasonable for a home gun safe since it is often kept within the living spaces of a home, and 50 degrees is pretty cool unless you grew up in the Arctic.

Gun Safe Surrounded by Steam

So, for the best compromise for storing both firearms and documents or other vital records in your safe, we’d err on the side closer to 30% humidity if possible, as excess humidity in enclosed spaces can accelerate corrosion and mold growth and just recommend you keep your safe in the coolest place that’s practical and secure in your home.

Remember, too dry is not ideal, either

You may be tempted to get the air inside your safe as dry as possible, but this is not a good idea, particularly if your firearms have wood, laminate, ivory, or bone stocks. If the air is too dry, these materials can shrink, crack, and warp, causing expensive or irreversible damage. Paper records, books, collectible currency, or essential documents inside your safe also need an appropriate humidity level to prevent drying and cracking. You wouldn’t necessarily think that paper items need a certain amount of humidity to prevent damage, but it’s a fact.

What causes moisture in a safe?

The primary source of humidity in a gun safe is the humid air in your home or dwelling, and it can seep past the door and any other openings in the safe over time, even if you keep the door locked. Most safes aren’t air-tight unless they’ve been sealed by their expanding, heat-activated door seals in a fire, and this is by design. Some airflow is essential to prevent mold, mildew, and condensation.

In some parts of the country, people use swamp coolers during the summer, which can add a lot of extra moisture to the air. If you live near a body of water or along the coast, the humidity in your area can be extreme, and even if your home air conditioning system’s refrigerant circuits remove some of the moisture, it may not be enough for safe and effective long-term storage inside your safe. The best way to check is with a hygrometer, or a moisture-level checking device, that will tell you how humid it is inside your safe.

Condensation can add moisture to the inside of your safe

Another contributing factor to excess humidity inside your safe can be temperature changes, whether in the environment around your safe, or by bringing cold, steel firearms into a warm room/safe after being outside in cold weather. An uncased, cold gun will often collect condensation, which can accelerate rust. That’s one problem. But suppose you put that dew-covered gun into your safe before it dries out and normalizes in temperature. In that case, that condensation can evaporate into the air inside your safe, and any liquid drops of water can saturate the floor or carpet inside your safe, raising the humidity levels.

Some experts recommend that guns that have been outside in the cold and then brought inside into a warm space should be left in their gun cases until they gradually come up to room temperature. Other experts worry that padded cases or "gun rugs" can absorb moisture and accelerate rust. They might advise you to immediately remove cold guns from soft cases and examine them carefully for signs of moisture. After they have come up to a stable temperature, wipe any condensation off with a soft, dry cloth (be sure to check below the stock line), and apply your choice of rust preventative before placing them inside your safe.

Gun safe dehumidifiers

A plug-in dehumidifier is the easiest and most effective way to reduce excess humidity inside your gun safe. Liberty Safe has a good collection of dehumidifiers and moisture absorbers for safes, some of which come standard with purchasing one of our higher-end models. Liberty’s Lincoln safes come with our Dry Rod dehumidifiers.

The Dry Rod Dehumidifiers heat to a touch-safe surface temperature of around 100-120 degrees Fahrenheit. This heat creates a natural convection that slowly circulates warm, dry air throughout the safe on a 24-hour basis. This increases the temperature of the air inside to several degrees above the ambient outside temperature. Expansion of the slightly warmer air forces the moist air outside through the small openings around the safe door, leaving the drier air inside. This type of dehumidifier is most effective when mounted horizontally on the bottom of the safe, but it can also be mounted against an interior safe wall.

Liberty’s Presidential and National Security safes come standard with our PEET dehumidifier. This design fits nicely into an inside corner of your safe (on the floor). It includes a vertical tube to accelerate the warmer air and create beneficial circulation within your safe. The Dry Rod and PEET safe dehumidifiers plug into an electrical outlet to move warm air through your safe to lower moisture and help prevent mold, mildew, corrosion, and rust. We recommend our electrical outlet kit for any electrical accessories inside your safe.

Silica gel packs and plug-in "rechargeable" dehumidifiers for dehumidifying a gun safe

Silica gel beads/packets are America's most common type of chemical desiccant, at least for use inside a safe. Calcium chloride-based crystals in products such as Damp-rid are also effective at absorbing moisture from the air and can help dry out enclosed spaces or other areas after a flood or broken pipe. However, the downside is that as the crystals absorb and then adsorb (hold moisture on their surface) water, they eventually become saturated and dissolve into a corrosive liquid, “brine,” that must be disposed of and replaced. Around guns, you don’t want either water or corrosive salts, so not many people would recommend this type of chemical desiccant around firearms. Also, calcium chloride crystals can’t be renewed by drying them out, unlike silica gel. So, if an electric dehumidifier isn’t going to be right for you, we’d recommend trying silica gel.

Silica-gel-based dehumidifier compounds commonly come in a perforated canister style or may be found in a “cordless” plug-in renewable style like Liberty’s rechargeable dehumidifier. Silica gel beads absorb excess moisture from the air, and these canisters or devices are filled with these beads and work without plugging in. The rechargeable type includes a visual indicator letting you know when the silica beads are saturated and need to be "recharged," which means you need to remove it from your safe and plug it into an electrical outlet for a few hours to heat the silica beads and drive the absorbed moisture out.

Canister types can be placed in a low oven to remove excess moisture and renew the silica gel beads’ humidity-absorbing properties. Then the device or canister can be returned to the safe. (Note: You should never leave this type of desiccant dehumidifier plugged in all the time… it’s intended to be placed inside your safe and only plugged in to renew it occasionally when needed. Please read and follow the instructions.)

If your safe is in a location without electrical power access, silica gel desiccants can be appropriate for keeping humidity at bay. However, since silica gel beads eventually become saturated, they only work for so long before they must be renewed or replaced. This means that if you don’t have the ability or desire to check on your safe’s condition frequently, this dehumidification strategy is probably not the best choice for you.

Again, whether you utilize an electric or chemical dehumidifier approach, you must regularly check the humidity levels in your safe to know whether you need to work toward drier or more humid air to stay within that golden 30%-50% zone.

Does dry rice work as a moisture absorber in gun safes?

Some people have recommended using dry white rice as a desiccant-type material for use in a gun safe. It can be effective sometimes, but we don’t recommend it for several reasons.

First, let’s look at how effectively rice can absorb excess moisture. Dry rice has the ability to absorb water due to its hygroscopic nature, or its ability to attract and absorb water molecules from the surrounding environment, making nearby objects and air drier and less humid. This is why placing objects into dry rice is often recommended when electronic devices like cell phones are mistakenly immersed in water and must be dried out. However, unlike other hygroscopic materials, rice is not deliquescent, meaning it does not dissolve in the water it absorbs. (Deliquescent materials keep absorbing water until they dissolve; when they dissolve, they release all the water they have acquired back into the environment. Not good.) When rice absorbs liquid water or water vapor, the attracted water molecules simply build up on the surface of the granules, and they swell, but it does not liquefy the rice grains.

It’s important to note that any water absorbed by rice does not stay in the grains forever. Rice can also lose water, making the surrounding objects more humid, a process known as water desorption (the opposite of absorption). This desorption happens because water vapor always seeks pressure equilibrium, with its molecules migrating from a high-pressure environment to a lower one until stasis is maintained. When an open container of dry rice is placed in a humid room, the rice will exchange water with the air until the vapor pressure in the air becomes equal to the vapor pressure in the rice grains. However, you’d need to use a LOT of rice to dehumidify a room. Probably more than is practical to use unless you’re in the grain storage warehouse business.

In a small, enclosed area like a bucket of flour, a drawer, a box of electronics, or a similar space, a breathable packet of rice can help keep humidity at bay. However, like silica gel desiccants, dry rice only absorbs as much humidity as possible to reach its vapor pressure limit. Then it stops “dehumidifying” and must be dried out in a low oven. Bugs are another potential downside when using rice in a gun safe. Rice is highly edible, and the starch in rice grains can quickly attract all kinds of insects and nasty critters, which you definitely don’t want in your gun safe around the carpet, wood stocks, or valuable documents and photos, which are also tasty starches that silverfish and other creatures crave. For this reason, we usually recommend against using rice inside a safe. If you try rice as a desiccant, monitor it regularly and use an in-safe hygrometer to ensure it’s doing its job.

Does a light bulb work for dehumidifying a gun safe?

A light bulb can effectively keep a safe free from excess moisture, but you have to be careful of a few things, and there are some caveats. First, conventional light bulbs are now difficult to find, and their LED replacements can build up a lot of heat in their housings, which can actually be too much for an enclosed space. Second, the commonly recommended 40- or 60-watt bulb can generate a lot of heat in a small, enclosed space. Remember the Easy Bake Oven? It used conventional light bulbs to bake cookies and cakes. If you use a conventional lightbulb to keep your safe dry, start with a 15W bulb and regularly check your safe’s humidity levels using a hygrometer.

Another issue you must be aware of is the light produced by a bulb near valuable firearms and documents. All electric lights produce UV light at some level, though some LED bulbs and sodium vapor lamps produce very little. Still, exposing collectible documents, photographs, and records to unnecessary light is discouraged. We’ve all seen how light exposure can fade clothing, paper, leather, carpet, and more, and in our view, it’s best to keep unnecessary light away from valuables, particularly a light source that needs to be on 24/7.

If you try to rig up a lightbulb in your safe, make sure to use quality electric cords and connections, and wrap any potential chafing points against the metal exterior of your safe with electrical tape or use rubber shrink-wrap protectors. Also, be sure to mount the bulb fixture securely so that it does not come in contact with the safe liner, carpeting, valuables, or any other material that could melt or combust. And always use a humidity monitor to help maintain your safe’s moisture levels in the proper zone.

Finally, if you’re the kind of person who walks around your house turning off all the light switches to save energy and money, running a lightbulb in your safe 24/7/365 might make the corner of your eye twitch. A dry rod dehumidifier uses less energy than most standard incandescent light bulbs. It is specifically designed to create the proper heat level for adequate air circulation and remove humidity inside your safe without the undesirable downside of potentially damaging the finish of valuable oil-finished stocks or essential photos and documents through light exposure.

Buy a Liberty Safe Dehumidifier

However you choose to maintain the proper humidity in your safe, just remember not to ignore it. Creeping rust, corrosion, mildew, and mold can be very tough to stop once they get a firm foothold, so it’s wiser to take the proper precautions beforehand and use the right gun safe dehumidifier.

*Made in the U.S.A. from U.S. and Global Parts.


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