Replace RV Hot Water Heater With Tankless

ByEric James Updated on

Ever found yourself showering in your RV, only for the hot water to suddenly run cold? Or perhaps you’re tired of waiting for a small tank to heat up, knowing you only have a few precious minutes before it’s gone? You’re not alone. The struggle for consistent hot water is a common challenge for many RVers, but there’s a game-changing solution that offers true freedom and comfort on the road: upgrading to a tankless water heater.

At OutwardLab, we believe in living outdoors smarter. That’s why we’re diving deep into how to replace your RV hot water heater with a tankless system. This comprehensive guide will equip you with the knowledge and confidence to tackle this significant upgrade, transforming your RV’s hot water experience from frustratingly finite to wonderfully endless. We’ll cover everything from the benefits and considerations to a detailed, step-by-step installation process, ensuring you can enjoy luxurious, on-demand hot water wherever your adventures take you.

Why Replace Your RV Hot Water Heater with a Tankless Unit?

Making the switch to a tankless system isn’t just about getting more hot water; it’s about enhancing your entire RV experience. The benefits extend far beyond a comfortable shower, impacting convenience, space, and even your environmental footprint.

The Perks of Endless Hot Water

Imagine showering without a stopwatch, washing dishes without rationing, or running a load of laundry with confidence. Tankless water heaters heat water on demand, meaning you only use energy when you need hot water. This eliminates the “recovery time” of traditional tank heaters, providing a continuous flow of hot water for as long as your water supply and fuel last.

Space and Weight Savings

Traditional RV water heaters come with bulky tanks that take up valuable storage space and add significant weight to your rig. Tankless units are often more compact and lighter, freeing up precious cargo capacity and interior real estate. This can be a huge advantage for smaller RVs, campervans, or overlanders where every inch and pound counts.

Energy Efficiency and Sustainability

Because tankless heaters only activate when hot water is called for, they don’t constantly heat and reheat a tank of water. This leads to a substantial reduction in propane or electrical consumption. This improved energy efficiency not only saves you money on fuel but also makes your RV lifestyle more eco-friendly and sustainable, aligning with OutwardLab’s core values.

Understanding Tankless RV Water Heaters: Is it Right for You?

Before you commit to the upgrade, it’s crucial to understand how tankless systems operate in an RV context and what unique considerations they bring.

How Tankless Systems Work in an RV

Tankless water heaters, also known as on-demand water heaters, work by passing cold water through a heat exchanger when a hot water tap is opened. A sensor detects the water flow, igniting a burner (typically propane in RVs) that rapidly heats the water to a set temperature before it reaches your faucet. This ingenious design means no waiting, no reheating, and no wasted energy.

Potential Downsides to Consider

While the benefits are compelling, it’s important to be aware of potential drawbacks. Tankless units often require a minimum water flow rate to activate, which can be an issue with very low-pressure campgrounds or water-saving fixtures. They also typically have a higher upfront cost than traditional tank heaters. Some users report a slight “cold water sandwich” effect, where a brief spurt of cold water comes through before the hot water arrives, especially if you turn the tap off and on again quickly.

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Planning Your Upgrade: Essential Considerations Before You Replace RV Hot Water Heater with Tankless

A successful tankless conversion starts with careful planning. These replace rv hot water heater with tankless tips will help you navigate the initial stages and ensure a smooth transition.

Choosing the Right Tankless Unit

Not all tankless water heaters are created equal, especially for RV use. Look for models specifically designed for RVs, which are built to handle vibrations and varying water pressures. Consider the flow rate (measured in gallons per minute, or GPM) and temperature rise capabilities. A higher GPM is better for multiple users or simultaneous use of hot water. Popular brands include Truma AquaGo, Girard, and Suburban.

Assessing Your RV’s Infrastructure

Your RV’s existing setup needs to be compatible.

  • Ventilation: Tankless heaters produce exhaust gases. Ensure your RV has adequate venting options or choose a model that can utilize your existing vent cutout.
  • Propane Supply: Tankless units can demand a significant amount of propane. Verify your propane tank size and regulator can handle the increased BTU requirement.
  • Water Lines: Most RVs use PEX plumbing. Ensure your existing lines are in good condition and that you have the necessary adapters for the new unit.
  • Electrical: Some tankless units require 12V DC for their control boards and ignition. Confirm your RV’s 12V system can support this.

Gathering Your Tools and Materials

Having everything ready before you start will save you time and frustration. Here’s a basic list of what you’ll likely need:

  • New RV tankless water heater unit
  • Sealant (butyl tape, silicone caulk)
  • Screwdriver set (Phillips and flathead)
  • Adjustable wrenches or crescent wrenches
  • PEX crimping tool and crimp rings (if modifying water lines)
  • PEX cutter
  • Pipe thread sealant or Teflon tape
  • Propane leak detector spray
  • Drill and various drill bits
  • Measuring tape
  • Safety glasses and gloves
  • Bucket and towels for water drainage
  • Wire cutters/strippers
  • Electrical connectors (if needed)

Step-by-Step Guide: How to Replace RV Hot Water Heater with Tankless

This section provides a detailed, practical guide on how to replace rv hot water heater with tankless. Remember, safety is paramount. If at any point you feel unsure, consult a professional RV technician.

Safety First: Preparing for the Installation

Before you touch anything, prioritize safety.

  1. Disconnect Power: Turn off all 12V DC power at your RV’s battery disconnect switch and unplug from shore power.
  2. Shut Off Propane: Close the main valve on your RV’s propane tank.
  3. Drain Water System: Turn off your RV’s water pump. Open a hot water faucet inside the RV to release pressure. Locate and open the drain plug on your existing water heater tank to completely drain it. Open all other faucets (hot and cold) to ensure the system is depressurized.
  4. Relieve Pressure: Carefully open the pressure relief valve on your old water heater to ensure all water is drained.

Removing Your Old Water Heater

This step involves careful disconnection and removal.

  1. Disconnect Water Lines: Using your wrenches, disconnect the hot and cold water lines from the back of the old water heater. Be prepared for some residual water to spill.
  2. Disconnect Gas Line: Carefully disconnect the propane gas line. Use a second wrench to hold the heater’s fitting steady to avoid damaging it.
  3. Disconnect Electrical: Disconnect any 12V DC wiring. Note which wires go where for potential reuse or simply cap them if not needed.
  4. Remove Mounting Screws: From the exterior of your RV, locate and remove the screws holding the old water heater in place.
  5. Gently Remove Unit: Carefully pull the old water heater unit out of its opening. It may be heavy, so consider having a helper.
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Mounting the New Tankless Unit

Positioning and securing your new unit is critical.

  1. Clean Opening: Thoroughly clean the existing opening, removing old sealant and debris.
  2. Test Fit: Carefully test fit the new tankless unit into the opening. Most RV-specific tankless heaters are designed to fit standard cutouts, but minor adjustments might be needed.
  3. Apply Sealant: Apply a bead of butyl tape around the flange of the tankless unit to create a watertight seal against the RV exterior.
  4. Secure Unit: Insert the tankless unit and secure it with the provided mounting screws. Do not overtighten, but ensure it’s snug and flush with the RV wall.

Connecting Water Lines and Gas/Electric

This is where your system comes to life.

  1. Connect Water Lines: Connect your RV’s cold water supply to the inlet of the tankless unit and the hot water outlet to your RV’s hot water distribution system. Use appropriate fittings and pipe thread sealant or Teflon tape. Ensure connections are tight but do not strip threads.
  2. Connect Gas Line: Reconnect the propane gas line to the tankless unit. Apply pipe thread sealant to the threads.
  3. Connect Electrical: Connect the 12V DC power wires according to the tankless unit’s manual. Typically, this involves connecting to a fused 12V circuit.
  4. Check for Leaks: Before fully closing up, open your propane tank valve and use leak detector spray on all gas connections. Look for bubbles, which indicate a leak. If you find one, tighten the connection and retest.

Testing and Sealing

The final steps ensure functionality and weatherproofing.

  1. Restore Water Pressure: Close all faucets inside the RV. Turn on your RV’s water pump (or connect to city water). Slowly open a hot water faucet inside the RV to purge air from the lines. Once water flows steadily, close the faucet.
  2. Test Hot Water: Turn on your RV’s 12V power. Turn on a hot water faucet. The tankless unit should ignite and begin producing hot water. Let it run for a few minutes to ensure consistent hot water.
  3. Final Seal: Once you’ve confirmed everything is working and there are no leaks, apply a thin bead of exterior-grade silicone caulk around the perimeter of the tankless unit’s flange for an additional weatherproof seal.

Post-Installation & Maintenance: Keeping Your Tankless System Running Smoothly

To maximize the lifespan and efficiency of your new unit, follow these replace rv hot water heater with tankless best practices and a consistent replace rv hot water heater with tankless care guide.

Initial Startup Procedures

After your first successful test, there are a few things to keep in mind.

  • Monitor Performance: Pay attention to the water temperature and flow rate during the first few uses. Adjust settings as needed according to the manufacturer’s instructions.
  • Check for Leaks (Again): Double-check all water and gas connections after your first few uses, just in case anything settled or shifted.

Routine Maintenance Tips

Tankless water heaters are relatively low maintenance, but some steps are crucial:

  • Descaling: Over time, mineral deposits can build up in the heat exchanger, especially in hard water areas. Periodically descale the unit (usually annually) by flushing it with a vinegar solution. Consult your unit’s manual for specific instructions.
  • Clean Vents: Ensure the exterior exhaust vent is clear of obstructions like dirt, leaves, or insect nests.
  • Inspect Gas Lines: Regularly check gas lines for any signs of wear or damage.

Winterizing Your Tankless System

Just like your RV’s plumbing, your tankless water heater needs proper winterization to prevent freeze damage.

  • Drain Completely: Follow the manufacturer’s instructions for draining the unit. This often involves opening drain valves and ensuring no water remains in the heat exchanger.
  • Bypass (if applicable): If your unit has a bypass kit, utilize it when adding RV antifreeze to your plumbing system to avoid filling the tankless unit with antifreeze.
  • Blow Out Lines: Use compressed air to blow out all water lines, including those connected to the tankless unit, to ensure they are completely dry.
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Troubleshooting Common Issues with Tankless RV Water Heaters

Even with careful installation and maintenance, you might encounter some common problems. Knowing how to address them can save you a service call.

  • No Hot Water/Unit Not Igniting:
    • Check propane supply and ensure gas valve is open.
    • Verify 12V power is on.
    • Ensure sufficient water flow rate (minimum GPM required for activation).
    • Check for error codes on the unit’s display.
  • Fluctuating Water Temperature:
    • This can be due to inconsistent water pressure.
    • Mineral buildup (descaling needed).
    • Air in the water lines.
  • Low Flow Rate:
    • Check for kinks in water lines.
    • Clean sediment screens at the inlet.
    • Consider descaling if buildup is suspected.

Frequently Asked Questions About Replacing Your RV Hot Water Heater with a Tankless System

Can I install an RV tankless water heater myself?

Yes, many RV owners with basic DIY skills and a good understanding of plumbing, gas, and electrical systems can perform this installation. However, it involves working with propane and high-pressure water, so safety precautions are crucial. If you’re uncomfortable at any point, it’s best to hire a certified RV technician.

How much does it cost to replace an RV hot water heater with a tankless one?

The cost varies significantly based on the tankless unit you choose, ranging from $600 to $1,500 or more for the unit itself. Installation costs, if hiring a professional, can add another $200-$500 or more, depending on the complexity and labor rates.

Do tankless RV water heaters use more propane?

While tankless units have a higher BTU output when actively heating, they only use propane when hot water is being drawn. Traditional tank heaters constantly burn propane to keep a tank of water hot. In many cases, the overall propane consumption of a tankless unit can be less over time, especially for extended stays or frequent hot water use.

What’s the best tankless water heater for an RV?

The “best” unit depends on your specific needs, RV size, and budget. Popular and highly-rated brands include Truma AquaGo (known for consistent flow and temperature), Girard (often more budget-friendly), and Suburban (a common OEM supplier). Researching reviews and specific features like GPM, temperature rise, and freeze protection is recommended.

Are there any specific water pressure requirements for RV tankless water heaters?

Yes, most tankless RV water heaters require a minimum water flow rate to activate and maintain consistent hot water. This can range from 0.5 GPM to 1.5 GPM depending on the model. Ensure your RV’s water pump or city water connection can provide this flow, especially when considering low-flow fixtures.

Upgrading to a tankless RV water heater is more than just a convenience; it’s an investment in your comfort, freedom, and self-sufficiency on the road. By following this guide and prioritizing safety, you can confidently make the switch and unlock a new level of enjoyment in your RV adventures.

Embrace the luxury of endless hot water and embark on your next journey with greater comfort and confidence. Stay safe, stay comfortable, and keep exploring!

Eric James
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