Build your own small dehumidifier using everyday household items like salt, a container, and a fan. This budget-friendly DIY project helps reduce indoor humidity, prevent mold, and improve air quality—perfect for closets, bathrooms, or basements.
Quick Answers to Common Questions
Can I use Epsom salt instead of table salt?
Yes! Epsom salt (magnesium sulfate) also absorbs moisture and has mild deodorizing properties. It’s a great alternative, especially if you want to avoid the salty residue of table salt.
How long does it take to see results?
You may notice a difference in air quality within 24–48 hours, especially in small, enclosed spaces. For best results, use a hygrometer to track humidity levels over time.
Can I add essential oils for scent?
Absolutely. Add 5–10 drops of essential oil (like lavender, eucalyptus, or tea tree) to the salt before placing it in the container. This adds a fresh scent and can help inhibit mold growth.
Will this work in a car?
Yes! Place a fabric bag dehumidifier under the seat or in the trunk to reduce foggy windows and musty odors. Replace the salt every 1–2 weeks during humid months.
Is this safe for wooden furniture?
Yes, as long as you place the dehumidifier on a tray or plate to catch any condensation. Avoid direct contact with wood surfaces to prevent water damage.
Introduction: Why Build a Small Dehumidifier?
High humidity isn’t just uncomfortable—it can damage your home, encourage mold growth, and trigger allergies. While commercial dehumidifiers work well, they can be expensive, use a lot of electricity, and take up space. That’s why building a small dehumidifier yourself is such a smart idea.
In this guide, you’ll learn how to make a simple, effective, and affordable dehumidifier using common household items. Whether you’re dealing with a damp closet, a musty bathroom, or a humid basement corner, this DIY solution can help. You don’t need special tools or technical skills—just a few materials and about 15 minutes of your time.
By the end of this guide, you’ll have a working dehumidifier that reduces moisture, improves air quality, and saves you money. Plus, it’s eco-friendly and safe to use around kids and pets. Let’s get started!
What You’ll Need to Build a Small Dehumidifier
Before we begin, gather these easy-to-find materials. Most are already in your kitchen or garage.
Visual guide about How to Build a Small Dehumidifier
Image source: m.media-amazon.com
Essential Materials
- Salt: Table salt, rock salt, or Epsom salt work best. Rock salt is especially effective because it’s coarse and absorbs moisture well.
- Container: A plastic container with a lid (like a food storage box) or a breathable fabric bag (like a cotton sock or mesh pouch).
- Perforated lid or fabric cover: If using a container, drill small holes in the lid or cover it with breathable fabric secured with a rubber band.
- Small fan (optional but recommended): A USB-powered desk fan or battery-operated fan helps circulate air and speeds up moisture removal.
- Hygrometer (optional): A small device that measures humidity levels so you can monitor progress.
- Measuring cup or scoop: To portion out the salt accurately.
- Scissors or drill: For making holes in the container lid.
Optional Upgrades
- Silica gel packets: Add a few to boost moisture absorption.
- Baking soda: Helps neutralize odors while absorbing moisture.
- Essential oils: A few drops of tea tree or lavender oil can add a fresh scent and mild antifungal properties.
- Decorative container: Use a mason jar or wooden box for a stylish look.
Step-by-Step Instructions: Building Your DIY Dehumidifier
Now that you have your materials, let’s build your dehumidifier. There are two main methods: the container method and the fabric bag method. Both work well—choose the one that fits your space and needs.
Method 1: The Container Dehumidifier
This version uses a sealed plastic container with holes in the lid. It’s great for small enclosed spaces like closets or cabinets.
Step 1: Prepare the Container
Choose a clean, dry plastic container with a tight-fitting lid. A 16–32 oz container works well for most small spaces. Make sure it’s food-safe if you’re placing it near clothing or linens.
Step 2: Create Airflow Holes
Using a drill or sharp tool, make 10–15 small holes (about 1/8 inch in diameter) in the lid. Space them evenly to allow air to flow through. If you don’t have a drill, you can poke holes with a heated nail or awl.
Tip: Don’t make the holes too large—you don’t want salt spilling out.
Step 3: Add the Salt
Pour 1 to 2 cups of salt into the container. Rock salt is ideal, but table salt works in a pinch. For extra odor control, mix in 1–2 tablespoons of baking soda.
Pro Tip: Add a few drops of essential oil to the salt before pouring it in. Tea tree oil has natural antifungal properties and smells great.
Step 4: Seal and Place
Close the lid tightly and place the container in the area you want to dehumidify. Position it where air can circulate—like on a shelf or inside a closet. Avoid placing it directly on wood surfaces; use a tray or plate underneath to catch any condensation.
Step 5: Add a Fan (Optional)
For faster results, place a small fan nearby and aim it toward the container. Even a USB-powered desk fan on low speed can significantly improve moisture removal. This is especially helpful in high-humidity areas like bathrooms.
Method 2: The Fabric Bag Dehumidifier
This method is simpler and more portable. It’s perfect for drawers, shoes, or small storage boxes.
Step 1: Choose the Right Fabric
Use a breathable fabric like cotton, linen, or mesh. A clean sock, handkerchief, or reusable mesh produce bag works well. Avoid synthetic materials like polyester—they don’t allow moisture to pass through.
Step 2: Fill the Bag
Fill the fabric bag with 1 cup of salt. You can mix in baking soda or a few silica gel packets for extra power. Tie the top with a string or rubber band, leaving some room for the salt to move and absorb moisture.
Tip: Double-bagging (placing the filled bag inside another breathable pouch) can prevent salt dust from escaping.
Step 3: Place in Target Area
Put the bag in the space you want to dehumidify. For example, place it inside a shoe box, a kitchen cabinet, or a gym bag. The fabric allows air to flow through while holding the salt securely.
Step 4: Refresh as Needed
Check the bag every few days. If the salt feels damp or clumpy, it’s time to replace it. You can dry used salt in the oven (200°F for 1 hour) and reuse it, though it may lose some effectiveness over time.
How It Works: The Science Behind DIY Dehumidification
You might be wondering: how does salt remove moisture from the air? It’s all about hygroscopy—the ability of certain substances to attract and hold water molecules.
Salt, especially rock salt, is highly hygroscopic. When humid air passes over the salt, water vapor sticks to its surface and dissolves into a brine solution. This process lowers the humidity in the surrounding air.
Unlike electric dehumidifiers that use refrigeration or desiccant wheels, this method is passive and chemical-based. It doesn’t require power, making it ideal for off-grid use or emergency situations.
The addition of baking soda helps neutralize odors, while essential oils can provide a pleasant scent and mild antimicrobial benefits. Silica gel, often found in shoeboxes or electronics packaging, also absorbs moisture and can be reused after drying.
While this DIY dehumidifier won’t match the power of a commercial unit, it’s highly effective in small, enclosed spaces where even a little moisture reduction makes a big difference.
Where to Use Your DIY Dehumidifier
Your homemade dehumidifier is perfect for small, damp areas where mold and mildew thrive. Here are some ideal locations:
Closets and Wardrobes
Clothes can develop a musty smell in humid closets. Place a container dehumidifier on a shelf or hang a fabric bag from a hook. This keeps fabrics fresh and prevents mold on shoes and bags.
Bathrooms
After showers, bathrooms can stay humid for hours. Place a small dehumidifier near the shower or under the sink. Add a fan for faster drying.
Kitchen Cabinets
Cabinets under the sink are prone to moisture from leaks or condensation. A fabric bag with salt can absorb excess humidity and protect stored items.
Basements and Crawl Spaces
Even in small corners, a DIY dehumidifier can help reduce dampness. Use multiple units if needed, and check them regularly.
RVs and Campers
Recreational vehicles often trap moisture. A small dehumidifier in the closet or under the bed can prevent mold and keep the air fresh during trips.
Storage Boxes and Suitcases
Before storing seasonal clothes or gear, place a fabric bag dehumidifier inside. This prevents musty odors and protects your belongings.
Maintenance and Troubleshooting
To keep your dehumidifier working effectively, regular maintenance is key. Here’s how to care for it and solve common issues.
How Often to Replace the Salt
Salt absorbs moisture until it becomes saturated. In high-humidity areas, this can happen in as little as 1–2 weeks. In drier climates, it may last 3–4 weeks.
Check the salt regularly. If it’s damp, clumpy, or forming a liquid brine, it’s time to replace it. Pour out the old salt (it can go down the drain or be composted if it’s just salt and baking soda) and add fresh salt.
Signs Your Dehumidifier Isn’t Working
- The air still feels damp or smells musty.
- Condensation appears on windows or walls.
- The salt remains dry after several weeks (may indicate low humidity or poor airflow).
If your dehumidifier isn’t working, try these fixes:
Troubleshooting Tips
- Poor airflow: Add a small fan to circulate air around the dehumidifier.
- Too much humidity: Use multiple units or increase the amount of salt.
- Salt not absorbing: Make sure the container has enough holes or the fabric isn’t blocked.
- Liquid pooling: If brine forms, place a tray under the container to catch drips.
- Odor persists: Add more baking soda or switch to Epsom salt, which has mild deodorizing properties.
Reusing and Disposing of Salt
Used salt can often be dried and reused. Spread it on a baking sheet and heat in the oven at 200°F for 1 hour. Let it cool before reusing. However, over time, the salt loses effectiveness and may develop impurities, so replace it entirely every few cycles.
Dispose of saturated salt down the drain with plenty of water, or compost it if it’s just salt and baking soda. Avoid pouring large amounts into septic systems.
Safety Tips and Best Practices
While this DIY dehumidifier is safe and non-toxic, follow these guidelines to ensure safe use:
- Keep away from children and pets: While salt isn’t highly toxic, ingestion in large amounts can be harmful. Store dehumidifiers out of reach.
- Use food-safe containers: If placing near food or clothing, avoid containers that may leach chemicals.
- Don’t overfill: Leave space in the container so salt can expand as it absorbs moisture.
- Monitor for mold: If you see mold growing near the dehumidifier, clean the area and increase ventilation.
- Avoid electronics: Don’t place dehumidifiers directly on or near electronics, as dripping brine could cause damage.
When to Upgrade to a Commercial Dehumidifier
While this DIY solution is great for small spaces, it has limits. Consider a commercial dehumidifier if:
- You’re dealing with a large room (over 200 sq ft).
- Humidity levels are consistently above 60%.
- You have chronic mold or water damage.
- You need continuous, automated dehumidification.
For whole-house or high-moisture situations, an electric dehumidifier is more effective. But for spot treatment and prevention, your DIY version is a fantastic, low-cost alternative.
Conclusion: A Simple Solution for Better Air Quality
Building a small dehumidifier is one of the easiest and most cost-effective ways to fight indoor humidity. With just salt, a container, and a few minutes of your time, you can create a device that protects your home, preserves your belongings, and improves your comfort.
This project proves that you don’t need fancy gadgets to solve everyday problems. Whether you’re fighting closet mildew, keeping your RV fresh, or just want to breathe easier, this DIY dehumidifier delivers real results.
Give it a try today. Monitor your humidity, enjoy fresher air, and feel good knowing you built something useful with your own hands. And remember—small changes can make a big difference.