How to Stop RV Condensation: Year-Round Humidity Control Tips for RV Owners
Published: 10/31/2025
The Ultimate Guide to RV Humidity Control: Protecting Your Investment
RV humidity control is arguably the most critical and least understood aspect of maintaining your home on wheels. Unchecked moisture is the primary culprit behind costly problems like persistent RV condensation, the rapid growth of mold and mildew, and even serious, long-term structural damage—all of which threaten the value of your RV investment.
The good news is that veteran RVers agree: successfully managing moisture requires a simple, adaptable, multi-pronged approach that changes with the season. This comprehensive guide covers the essential year-round core strategies, including accurate humidity monitoring and proactive airflow management, and provides specialized, seasonal tactics—detailing the best dehumidifiers and heating solutions for optimal control in both hot/humid summers and cold, condensing winters.
Dive into this ultimate guide for a complete breakdown of the best monitoring tools, ventilation techniques, and seasonal dehumidifying strategies used by Rvers, van life and campers to keep their rigs dry, healthy, and protected all year long.
The Year-Round Core Strategy: Monitoring, Ventilation, and Prevention
Regardless of the weather outside, your first steps should always be to monitor and manage the sources of moisture.
1. Monitor Relative Humidity (RH)
• The Essential Tool: Every RVer needs a hygrometer Wi-Fi or Remote Sensor for Monitoring. You need to keep the Relative Humidity (RH) between 40% and 60% (many full-timers aim for the tighter range of 30-50% in cooler weather). If the RH is too high, it's time to act.
Recommended Monitoring Tools:
Digital Hygrometer/Thermometer
Cellular Temp and Humidity Monitor
2. Maximize Airflow and Ventilation
• Exhaust Fans are Key: Always run your bathroom vent fan while showering and your range hood fan while cooking. This is the fastest way to expel humid air immediately.
• Cross-Breeze Power: Crack a window and a roof vent (or two windows on opposite ends) to create a cross-breeze. This is the single most effective, low-power method.
• Open Cabinets: Keep closet and cabinet doors slightly ajar to allow airflow into stagnant, dark spaces where mold thrives.
• Invest in a Fan: Use a small circulating fan to keep air moving around the main living area, especially near cold walls or windows where condensation is likely.
3. Minimize Moisture-Adding Activities
• Cook Outdoors: Whenever possible, cook outside (use a grill, portable induction cooktop, or Instant Pot vented outdoors). Indoor boiling adds a massive amount of moisture.
• Dry Laundry Off-Site: Avoid drying wet clothes and towels inside. Use a commercial laundromat dryer or hang them outside. Use rapid drying towels like these waffle weave.
• Wipe Down Surfaces: After showering or cooking, quickly wipe down bathroom and kitchen surfaces where condensation has occurred.
Strategy for Summer & Humid Climates
In warm, humid areas, the air outside is the main source of the moisture trying to get in. Your goal is to cool and dry this air.
• Air Conditioner (A/C) is Primary: The A/C unit is your primary dehumidifier in summer. As it cools the air, it pulls moisture out, dripping it outside. Running the A/C is the easiest way to drop humidity quickly.
• Dedicated Compressor Dehumidifier: If it's warm and humid, but you don't need the A/C running constantly, a dedicated compressor-style electric dehumidifier is the way to go. These are the most power-efficient dehumidifiers in warm temperatures to maintain your ideal RH level.
Compressor Dehumidifier for a large RV
Compressor Dehumidifier for Small Space
Passive Absorbers: For very small, enclosed areas like closets, storage bays, or under the sink, passive chemical absorbers (like DampRid) are effective. They use calcium chloride crystals to wick moisture from the air, but they are generally too small to treat the main living area.
Hanging DampRid/Moisture Absorbing
Renewable Moisture Absorber EvaDry
Strategy for Winter & Cold Climates
In cold weather, the main source of moisture is human activity (breathing, cooking, showering), which condenses instantly on cold surfaces like windows and walls.
• RV owners prefer a desiccant-style electric dehumidifier in the winter because they work significantly better in colder temperatures 65F than standard compressor-style units, which can freeze up and become inefficient.
• Ventilation with Heat: This is a crucial tactic. RVers often run a small electric ceramic space heater (which produces dry heat) simultaneously with cracking a window/vent and running an exhaust fan. This introduces dry air while expelling the warm, humid air, preventing condensation.
• Avoid Propane Heat (If Possible): Propane furnaces and stovetops produce water vapor as a byproduct of combustion, drastically increasing indoor humidity. Many full-timers switch to electric heat (when connected to shore power) to avoid this.
An Oil-Filled Radiator Heater is your best supplemental heat choice because it provides consistent, dry, radiant heat that prevents condensation, all while running safely on your RV's limited electrical system. This Air Choice 700W is recommended becauese it has a fixed, low power draw.
Insulation: Use Reflectix or window insulation film on single-pane windows to raise the surface temperature of the glass, which stops moisture from condensing directly on the cold pane.
Use an induction cooktop. These utilize electromagnetic energy to heat cookware directly without burning any fuel, which means the cooking process itself adds zero water vapor to the RV's air. This is a critical advantage over traditional propane stoves, where combustion chemically releases water and carbon dioxide into the enclosed living space. By eliminating this internal source of humidity during meal preparation, induction significantly reduces the risk of condensation, mold, and mildew buildup inside the small cabin environment.
The NuWave PIC Flex is an excellent choice for RVs and boats, primarily because it's designed with adjustable wattage (usually 600W, 900W, 1300W, and 1500W). This flexibility is crucial for cooking when you are running off a limited power source like a small inverter or a campground's lower-amperage hookup, helping you prevent electrical overloads. The compact size and included pan also make it a convenient, ready-to-use solution for small galleys
The Duxtop Portable Induction Cooktop 9600LS is highly recommended for RV and boat use, as it balances great performance with low-power flexibility. Its numerous precision settings allow for efficient, reliable cooking while carefully managing the electrical draw on limited mobile circuits.
For more information about keeping your RV mold and mildew free, see this blog.
Van or Camper Life Practices to Minimize Moisture
Ventilation removes humid air and replaces it with drier air from outside.
1. Ceiling Fan: A high-quality bidirectional roof fan like a MaxxAir fan It should be used:
- While Cooking: Always set to exhaust (pulling air out) and crack a window nearby to create cross-breeze.
- While Sleeping: Set to a low, quiet exhaust speed to remove the moisture produced overnight.
2. Passive Vents: Ensure lower and upper passive vents are always clear. Airflow from low to high is essential for moisture escape.
Dehumidification (The Secondary Solution)
While ventilation is primary, active dehumidification can help in extremely rainy or humid conditions.
- Desiccants: Products like DampRid (calcium chloride) absorb moisture from the air and collect it as water. These are inexpensive and require no power, but they are most effective in small, enclosed spaces like cabinets, not the main cabin.
- Electric Dehumidifiers: Small thermoelectric Peltier type dehumidifiers use low-power, but they are only truly effective in removing residual moisture and are not powerful enough for the whole van in high-humidity climates.
Wipe Down Windows: On cold mornings, condensation will form on windows and uninsulated surfaces. Wipe these surfaces dry immediately with a microfiber cloth and wring the cloth outside. Or use a window vacuum squeegee, squeegee the condensation and pour the collected water outside.
Heating Your Van or Camper
Effective heating must be safe, efficient, and dry.
We recommend three primary types of heaters for van life, each with trade-offs in efficiency, safety, and moisture production. Diesel, Electric Ceramic and Propane Catalytic Heater.
Diesel Air Heater (Most Recommended): Fueled by diesel drawn from the van's main fuel tank, this type is extremely efficient and produces dry heat because the combustion process occurs entirely outside the living space. It is very low power draw (for the fan) but its main drawback is the complex initial installation required to mount the unit and run the necessary fuel and exhaust lines.
Budget All-in-One: This Vevor is often the choice for quick installation, as all components (heater, fuel tank, pump) are housed in one box. It's great for beginners, but the large 8KW size can be overpowered for small, well-insulated vans, leading to inefficient cycling.
Mid-Range / Best Value: Planar Autoterm 2D (or 4D) has high quality components, great reliability, and superior performance at high altitudes (up to 8,500 ft). The Planar 2D (around 7,000 BTU) is ideally sized for most vans (100–150 sq ft). It requires a more complex, permanent installation by tapping into your van's main diesel tank or using a separate, custom-mounted tank.
Premium: Webasto or Eberspächer. Highest quality, quietest operation, best performance at extreme altitudes. These are the "gold standard" top-tier quality control but at a significantly higher price.
Electric Ceramic Heater:
- Running on 120V shore power, these heaters provide absolutely dry heat with zero moisture or CO risk. Their downside is their high power consumption, making them only feasible when you are plugged into a campground (shore power) or if your van is equipped with a high-capacity inverter and lithium battery bank. We like this Dreo Atom One
- The Micro-Draw Ceramic heaters offer a practical balance of warmth and low amperage draw. They're designed for personal or spot heating, not warming the whole van, which is exactly why they save your batteries. These are used Off-Grid/Battery: Lasko Ceramic Cube 400W Ceramic Heater or the Amazon Desktop Ceramic Heater 500 W
Propane Catalytic Heater (Ventless): These heaters use small propane tanks for quick, portable heat and are easy to use. However, they carry a high safety risk due to potential Carbon Monoxide (CO) production and, critically for moisture control, they do add significant water vapor to the air as a byproduct of combustion. If used, this type requires a STRICTLY monitored CO alarm and heavy ventilation.
The Top Catalytic Choice: Olympian Wave For those prioritizing efficiency and dryness, the Camco Olympian Wave (models like the Olympian Wave 3 or Wave 6) is frequently cited as the superior option. This is because it uses true catalytic heating, which is a flameless chemical process where propane reacts on a platinum surface. This method is exceptionally fuel-efficient, draws no electricity, and, most importantly for a van, produces much less moisture (water vapor) during combustion compared to other types of propane heaters. The Wave 3 (around 1,600 to 3,000 BTU) is ideal for smaller vans, while the Wave 6 (up to 6,000 BTU) is better suited for mid-sized campervans.
The Popular and Portable Alternative: The Mr. Heater Portable Buddy (and its siblings, the Little Buddy and Big Buddy) is arguably the most popular portable heater for this use. It's beloved for its ease of use, instant radiant heat, and built-in safety features like a tip-over shut-off switch and an Oxygen Depletion Sensor (ODS). It's very versatile, running off small 1lb propane canisters or a larger 20lb tank with an adapter hose. However, it's crucial to understand that the Mr. Heater series is a radiant heater, not a true catalytic one. Radiant heaters produce a significant amount of water vapor as a byproduct of combustion. While great for a quick blast of warmth, if you run it for long periods, it can quickly lead to severe condensation on your van's interior surfaces.
Diesel Heater Safety: Air Quality and Carbon Monoxide Monitoring
Monitoring the air quality is non-negotiable, especially when running any type of combustion appliance (gas cooktops, propane heaters, diesel heaters).
- The most recommended CO Alarm units for RVs and campervans are manufactured by MTI Industries (Safe-T-Alert) and RV Safe. MTI Industries Safe-T-Alert e.g., 25, 35, or 45 Series Dual Alarm They draw minimal power, are hardwired to your house battery and meet all necessary safety standards.
- RV Safe CO/LP Dual Alarm: Another highly-rated brand that is often recommended as a universal replacement, featuring highly selective sensors to reduce false alarms.
- While the UL-certified RV alarms are great for meeting safety standards, some van dwellers prefer a second, dedicated CO monitor that is more sensitive and alarms faster, especially at low concentrations (PPM). The top recommended is Forensics Detectors Low-Level CO Detector (Vehicle Model FD-CAR002): This type of detector is designed to alarm faster (sometimes in 60 seconds) at lower PPM levels (like 25 ppm) than a standard household alarm (which might be slower to alarm at 70 ppm). They are specifically designed for vehicles where a quick response is vital.
Join Our Journey Aboard Healthy Boat Living
If you’ve read this far, you know that protecting a valuable mobile investment—like an RV—is a full-time job. Whether it’s managing humidity control (which is even more critical when surrounded by water!) or mastering space-saving organization, the lifestyle is all about efficiency.
Why are we sharing this with you? Because for my family, our RV is a boat!
I’m Maria Faires, a Captain, Dietitian, and Personal Trainer, and I’ve traded highways for high tides. My husband, George, and I are sharing our adventures, tips, and hacks from our 30-foot Tollycraft motor vessel, Little Bear, currently cruising the breathtaking San Juan Islands and beyond.
Just like RVers, boaters have to master tiny kitchens, limited power, and the art of minimalism. Our journey is dedicated to sharing everything that makes small-space living healthy and amazing on the water:
Mastering space-saving packing and genius hacks.
Small space workouts andoutdoor fitness routines.
The best tips for cooking in a small space with limited resources.
Stunning decor inspo, style, and magical experiences.
Whether you eventually trade your tires for a tide or simply enjoy following another small-space adventure, we're here to share the voyage!
Categories: Healthy Boat Living RV and Camping
Tags:
