Thinking about upgrading to a tankless water heater in your RV? Before diving into the installation, there’s an important question to consider. Can you actually replace your standard water heater with a tankless model? The short answer is yes. But whether this is a DIY job or something best left to a certified RV technician depends on your experience, tools, and attention to detail.
If you’re still weighing the pros and cons of tankless water heaters, this guide will help you make an informed decision. We’ll walk through what to consider before starting, outline the basic installation steps, and show you where to find compatible models and installation services.
Key Takeaways
- Compatibility & Installation: Replacing a traditional RV water heater with a tankless model is possible, especially with a retrofit kit, but complexity varies—gas-only units are simpler to replace than gas-electric models, which may require electrical modifications best handled by professionals.
- DIY Considerations: While detailed steps and tool lists are provided for DIY installation, key tasks like LP gas and electrical work are recommended for certified technicians due to safety concerns and code requirements.
- Cost & Support: Tankless RV water heaters range from $200–$700, with retrofit kits adding $50–$100; Camping World locations offer expert guidance, compatible models, and professional installation services.
Can You Install a Tankless Water Heater in Any RV?
Theoretically, an RV tankless water heater can replace any gas-only or gas/electric water heater. However, the installation will be much easier if you find a compatible model with a retrofit kit. In general, replacing a gas-only traditional water heater with a tankless model is easier because it won’t require the additional rewiring or termination of the 120VAC electric heating element.
Many tankless water heater manufacturers offer retrofit kits that make the replacement easier. Without one of those kits, you’ll likely require the services of a trained RV technician.
Perhaps most importantly, tankless RV water heaters rely on 12-volt DC power and burn propane to heat water. If replacing a traditional water heater with a 120-volt electric heating element, the 120VAC wiring must be removed or terminated in a listed enclosure. This includes capping conductors with listed wire nuts and wrapping them in electrical tape. These additional installation steps are best completed by a professional technician.
How To Install a Tankless Water Heater in an RV
While a trained technician is best suited to handle the LP and electrical installation steps required for a tankless water heater installation, we’ll outline the general steps for interested DIYers.
Technician Tip: These steps will vary based on the water heater manufacturer. Precision retrofit kits are the best way to ensure the process is as safe, efficient, and accurate as possible.
Tools Required
Allowing for potential variance due to the many tankless water heater manufacturers out there, these are the most common tools you’ll need for this installation:
- Wire cutters/crimping tool
- 1-1/16” socket (for drain plug)
- Wrench set
- Cordless drill with Philips and/or #2 square bit
- Needle-nose pliers
- Plastic putty knife
- Utility knife
- Small plastic pry bar (optional)
- Small folding table (optional)
- Electrical connectors
- Electrical tape
- Plumber’s tape
- Lap sealant
- Towels
- Foam or butyl tape
- Caulking gun
Technician Tip: Some of these tools may come with your water heater retrofit kit.
Turn Off Power and Propane
First, unplug your camper from AC power sources (30/50 amp or 120VAC). You must also remove the power cable from the negative terminal on your RV battery to ensure no 12VDC power is connected to the water heater.
Completely shut the valves on top of all RV propane containers. For additional safety, consider disconnecting LP containers from their pigtail connectors if completing this installation on a towable camper. Once the valves are closed and/or containers are disconnected, turn on a cooktop burner inside your RV to bleed as much LP gas from the lines as possible. Light a burner and let it burn until the flame dies before turning the gas off at the cooktop.
Drain Water
Use your low-point drain valves to remove water from your RV’s plumbing system. You’ll also need to remove the drain plug from the water heater to drain any water remaining in the tank. These methods rely on gravity alone to remove water from the system. For a more complete method, consider closing low-point drain valves and turning on your water pump. This pressurizes the system to aid water draining from the water heater tank.
Prep the Old Heater for Removal
Use a utility razor or plastic putty knife to remove the sealant around the edges of the water heater. This step requires great care to avoid scratching or damaging the sidewall surrounding the water heater opening.
Then, remove all screws holding the heater in the opening. There may also be foam or butyl tape holding the heater in place. A small plastic pry bar may be handy to break the bond between that tape and your RV’s sidewall.
Once the seal is broken, place a small folding table next to your RV. This gives you a flat surface on which to set the water heater once you disconnect water, electric, or LP lines.
Technician Tip: A small amount of sealant behind the water heater’s exterior flange may hold the LP line in place. This sealant may be removed to pull the LP line out. It may also be cut away, but be careful not to cut the LP line, as it will be reused.
Disconnect Water, Propane, and Electric
Remove the connections to the main systems powering your water heater’s operation. For gas-electric models, you must disconnect water, propane, and all electrical connections (12V and 120VAC). For gas-only models, you won’t have 120VAC electrical connections to remove.
Depending on how your RV is plumbed, you may be able to access the back of the water heater from inside to more easily remove plumbing connections before pulling the old heater out of the opening. If you cannot access the back of your water heater from inside your coach, partially slide the old water heater out of the opening to access the connections.
Technician Tip: Even with your RV’s water system drained, residual water may remain in plumbing lines. Place towels below the water lines before disconnecting them to soak up residual water that may leak out.
Disconnect the LP line and water connections first. This will often provide additional flexibility to slide the heater further out of the opening and/or onto the table to access the electrical connections. Once the electrical wiring is disconnected, transfer the heater to the table and remove any fittings you’ll reuse for the new tankless water heater.
Make Any Necessary Alterations
As you prepare to install the new tankless water heater, set it on a table outside the opening. With the correct table height, the water heater can be partially inserted into the opening to provide the elbow room needed.
Test that your water lines reach the new heater’s inlet and outlet connections. Avoid pulling on the water lines at all when attempting these connections. You may need to lengthen, shorten, and/or add new fittings to avoid stressing or kinking the water lines. The same is true for the LP line and electrical wiring.
Technician Tip: Note the position of the blocking that supported the original water heater. Because tankless models aren’t as deep as traditional designs, the blocking may be moved to support the new water heater adequately.
Note the positions for the water, propane, and wiring connections to double-check that they can be made without stressing any wiring or water/LP lines.
Connect Water, Propane, and Electric
Start by connecting the gas line and the hot and cold water lines. Regarding electrical, the first connections will be 12VDC power and ground. You must identify the two wires that supplied 12VDC power and ground to the original water heater.
Technician Tip: If you had a gas-electric water heater, you’ll also have a 120VAC power supply, which must be properly terminated in a listed enclosure. Your new tankless water heater must be connected to 12VDC power (not 120VAC!), which allows you to turn it on using the existing ‘Gas’ switch on the control panel inside your RV.
With the new heater connected to propane, hot and cold water, and 12VDC power and ground, set the heater into the opening.
Mount the Control Panel
You must also choose where to place the tankless heater’s control panel. Most campers prefer their control panel on a bathroom wall, which makes it easier to adjust water temperature before showering. Other potential locations include a kitchen wall, any wall adjacent to the bathroom, or inside bathroom cabinetry.
Technician Tip: Installing the control panel will require additional wiring to mount it in your desired location. Check with the water heater manufacturer on the recommended wiring gauge if it did not come with your retrofit kit.
Most RV technicians will fish wire from their preferred panel mounting location back to the control panel wiring on the back of the water heater. The panel itself mounts to the wall using included screws (with most kits), but it will likely require using a utility knife to make a small incision in the wall to connect the wiring before mounting the panel.
Test New Heater
Before you can function test the new water heater, connect to city water or fill the tank and turn on the water pump. Purge all air out of the system at every faucet and the low point drains one at a time. Perform an LP gas leak test (best done by a certified technician using specialized tools) using soapy water at the LP gas line connection.
After that initial test and double-checking that all connections are tight and unused electrical wiring is capped correctly and insulated, restore power and propane to the system by reconnecting the cable to your battery’s negative terminal and opening an LP container valve. You must also fill your fresh water tank or connect to city water.
Then, turn the water heater on. Using the wiring method outlined, the On/Off switch on the exterior of the water heater must be On, the Gas switch used for the original water heater must be on, and the control panel must be turned on. You can then open any hot water fixture and check that the heater operates as intended.
Technician Tip: Because you bled propane out of the lines, you may need to cycle the water heater several times to check operation. Lighting the stovetop burners until they run blue and steady will speed up this process. If you receive an Error code on the water heater control panel, check the owner’s manual for code references.
Secure Heater and Seal Edges
To complete the installation, place foam or butyl tape around the inside edges of the water heater door kit. Place the door on the opening and secure it using the screws included in the kit. Use a caulking gun to run a bead of lap sealant around the entire edge of the door. Use a plastic putty knife, scraper, or edging tool to clean up that bead of sealant.
Technician Tip: It may be helpful to remove the exterior door to run lap sealant around that edge. Avoid closing the exterior door until the lap sealant is completely dry. Closing the door before it’s dry can cause it to get stuck in the sealant, requiring you to remove and reseal portions so the door operates as intended.
How Much Does it Cost to Install an RV Tankless Water Heater?
Replacement tankless water heaters for RVs usually cost between $200 and $700. Some models don’t come with the exterior access door, so factor that additional expense in if yours doesn’t. Additionally, an average retrofit kit may cost between $50 and $100. If you choose a professional installation service to upgrade your water heater, labor rates vary by shop and location. Because tankless water heaters use a remotely mounted control panel and wiring harness, they require additional installation time.
Where to Find a Tankless Water Heater Replacement
(And Have It Installed!)
Many of the best RV brands are making their newest models with tankless water heaters from manufacturers like Suburban and Girard. When choosing a new tankless water heater, consider important factors like water consumption, winterization, design, dimensions, and the cost of the water heater and any required installation services.
Retail experts at any Camping World location can help you find a compatible tankless water heater replacement for your RV. Ask about a retrofit kit if you’re replacing a traditional water heater with a tankless design. With the heater and retrofit kit, our Service Department can assist with the removal and replacement.
You can also explore these two gear guides to compare the criteria for selecting traditional vs tankless RV water heaters:
What questions do you have about installing a tankless water heater in an RV? Let us know in the comments below.
