Information Guide

How To Convert RV Water Heater To Tankless

Every RV will come with a standard water heater. But, they’re not ideal on the move. Here’s how to convert an RV water heater to tankless.

by Matt Moran

When in an RV, you want to make sure you have constant access to hot water. The best RV tankless heaters can help you with that.

So, if you need to know how to convert an RV water heater to tankless, make sure to stick around! You never want to be stranded with cold water only. 

Your standard RV will come with a water heater tank. However, a tankless option is going to be a lot lighter. There are many benefits and disadvantages to consider. So, are RV tankless water heaters worth it? 


  • Convenience
    These appliances offer hot water when you want it. They’re very convenient and give you warm water immediately. You won’t need to wait for the water to get hot.
  • Energy Efficient
    They also don’t waste any water, so you can save on refilling and feel confident that you’re being kind to the environment. They heat on demand, so they aren’t heating water constantly either (like a tank would). 
  • Space Saving
    These appliances take up less space overall. If you don’t have a large RV or trailer, then this is the better option.
  • Longer Lifespan
    Finally, they offer a much higher lifespan than a water heater with a tank. On average, a tankless water heater lasts out 19 years, while a tank heater lasts 11 years. You can save some money on making repairs as well- when you replace RV water heaters with tankless heaters, you have better access to parts.


  • Initial Cost Is On Higher Side
    Tankless water heaters are much more expensive than the traditional tank water heaters. They can cost you between 40 and 80 percent more upfront.
  • Special Requirements In Installation
    They also require a pro to install them since they need dedicated systems. You might even need to change out the gas pipes for them to work properly.
  • Restricted Simultaneous Use
    You can’t run two hot water taps at once. 
  • Inconsistent Temperature
    The temperature might fluctuate somewhat when using hot water.
Women Relaxing With Her Dog Out Front Of RV

Considerations Before Undertaking A Tankless Conversion 

Size Of The Tankless Water Heater & The RV  

You want to make sure the tankless appliance can heat enough water for your RV. Additionally, you need to know where the venting system goes and where the appliance hooks up to your natural gas. 

Number Of Individuals Needing Hot Water At The Same Time  

These water heaters aren't the best at supplying more than one person with hot water at once. For example, if someone wants to take a shower while someone else runs a dishwasher, the tankless water heater may be hard-pressed to supply both people with warm water. 

If you have an RV where you suspect more than one person will be using hot water at once, you may need to consider your other options first. 

Venting System

The natural gas heater needs to be vented correctly- this is where you want a pro to take a look at your appliance and RV. An appliance on the inside of your RV needs to vent outside. You’ll want to ask the pros about the options you have; it’s unique to your RV. 

RV With Tankless Water Heater

How To Convert A RV Water Heater To Tankless (DIY Replacement)  

With an RV tankless water heater installation, you need to make sure everything goes properly. There’s natural gas involved for the heating, and you may need to change out some of the pipes. We recommend getting a professional plumber to assist you. 

1. Take Safety Precautions 

First, make sure that you isolate all the systems that connect with your old heater. That includes propane, water connections, and electricity. Shut all of them down. Then, you can drain the old tank. You’ll need to allow it quite some time to empty completely. 

2. Disconnect Utilities 

Now, all utilities should be shut down, and the tank is fully empty of water. You'll want to disconnect the old water tank from all utilities. You should take a picture of the hook ups to make sure you reconnect everything properly. 

3. Removing the Tank 

After everything’s disconnected, you can remove your old water heater. Use a drill to remove every mounting fastener. Then, remove the mounting panel off the RV. With that out of the way, you can pull the old water heater forward. 

Make sure you remove all of the old sealant once it’s out. It could get in the way of installing your new machine. 

4. Add the Tankless Heater 

Move the heater into the space that you just opened up. You want to make sure that it’s level and sitting perfectly in place. It helps if you have a buddy make sure that all of the mounting holes line up with the old holes. You can always drill new holes if you have to. 

5. Reconnecting the Lines 

You’ll next need to reconnect the water and natural gas lines to your appliance. You’ll want to work slowly and make sure everything lines up and connects correctly. Then, go back over all the pipes and tighten every piece again. 

6. Installing the Thermostat

Next, you need to set up the temperature control switch beside your heater. You’ll need to use a drill to open a hole next to the panel. This allows the wiring on the thermostat to connect with the water heater. The thermostat goes in the RV. 

If you prefer to leave the conversion to a professional expert, fill in the form below for a free quote in your local area!

Maintaining Your New RV Tankless Water Heater  

Next, you’ll need to know how to maintain your new heater. You’ll want to know how to efficiently flush the water heater. You need to do this at least twice a year to keep everything clean.  

Always make sure the power is cut and the water is off first. You’ll also need access to white vinegar, which is the cleaning element we recommend that you use. This process takes care of mineral deposits. 

You also might want to have a plumber look at it yearly. They’ll know what signs of damage to keep an eye out for. 

People Also Ask (FAQ)

What is the standard size of a water heater for an RV?  

Most RV water heaters are six or 10 gallons. You can find them in different sizes, however. These include 4 and 16 as the most common options. 

Can you run out of hot water with a tankless water heater?  

When you perform a tankless water heater conversion, you get endless hot water. The machine heats the water as you use it, so you never run out. 

Should I leave my RV water heater on all the time?  

It's safe to leave the appliance on 24/7, even if you're driving the RV! However, many people choose to shut it down to save on energy while driving. 

How do you winterize an RV tankless water heater?  

Start by turning off the power, then disconnect the water supply. You’ll want to make sure all the water comes out of the pipes. There should be nothing left inside to freeze. 


Overall, you can perform a replacement on your current tank and receive many benefits from it! We recommend looking into the options you have for your unique RV or trailer. 

Matt is a freelance writer, English graduate, & keen traveler from the UK. As a specialist plumbing expert, he enjoys writing about everything there has to do with at-home plumbing products & related problems. When he isn’t writing, he’s usually drinking coffee or planning his next adventure. In his spare time, he also runs his own blog all about digital nomad life.