Understanding RV Water Heater Basics

Whether you're planning your first RV adventure or upgrading your rig for full-time travel, one thing’s for sure: hot water matters. From washing dishes to taking a warm shower after a long hike, your RV's water heater plays a crucial role in your comfort on the road. In this guide, we’ll break down the RV water heater basics, explore different types, and help you decide which system is right for your lifestyle.

An RV water heater is a compact appliance designed to heat water for your motorhome or travel trailer. Unlike residential systems, RV water heaters are built to be space-efficient, energy-conscious, and compatible with mobile living.

Most RV water heaters hold between 6 to 10 gallons of water, though tankless models offer on-demand hot water without storing it — more on that later!

When it comes to heating water in your RV, there are two main types of systems: tank water heaters and tankless water heaters. Each has its own advantages, limitations, and ideal use cases depending on your travel style and comfort preferences.

RV water heaters with tanks are the traditional option. There are three types, depending on their fuel supply:

• Propane: Heats water using LP gas. Great for off-grid camping.
• Electric: Uses shore power or generator electricity.
• Dual-Fuel: Offers flexibility with both propane and electric options.

Tank water heaters are still found in many RVs today, especially older or entry-level models. These systems typically hold between 6 to 10 gallons of water, but some hold as little as 4 gallons and others as much as 16 gallons. They heat the water using propane, electricity, or a combination of both (dual-fuel). Once the water in the tank is heated, it's stored and ready for use. However, once that hot water is used up, you’ll need to wait for the tank to refill and reheat — something that can take 20 to 30 minutes depending on the model and fuel source.

Propane-powered tank heaters are great for off-grid camping since they don’t rely on shore power, while electric models are ideal when you’re plugged in at a campground. Dual-fuel models offer the best of both worlds, giving you flexibility based on your power situation. While tank heaters are generally reliable and cost-effective, they do have limitations in terms of hot water supply and energy efficiency.

Also known as on-demand water heaters, tankless RV water heaters heat water as you use it. That means no waiting and no running out.

Benefits of tankless units include:

• Unlimited hot water
• Energy-efficiency
• Compact design

Tankless water heaters are a modern upgrade that many RVers are turning to for greater convenience and comfort. Instead of storing hot water in a tank, these systems heat water instantly as it flows through the unit. This means you get unlimited hot water — perfect for longer showers, washing dishes, or traveling with a family.

Tankless systems are typically more energy-efficient because they only operate when hot water is needed, reducing standby heat loss. They also take up less space, making them ideal for compact RVs or those looking to maximize storage. One of the top choices in this category is the Furrion tankless water heater, which is specifically engineered for RV use. It features smart temperature control, fast ignition, and built-in safety features, making it a reliable and high-performance solution for modern RVers.

Understanding how RV water heaters function can help you operate them more efficiently and troubleshoot issues when they arise. While the mechanics vary slightly between tank and tankless models, the core concept is the same: heating cold water using a fuel source (propane, electricity, or both) and delivering it to your faucets and shower when needed.

With tank models, water is heated and stored until needed. Once depleted, you’ll wait for it to reheat. With tankless models, sensors detect water flow and ignite the burner instantly, providing continuous hot water. Most systems include a thermostat, pressure-relief valve, and control panel for temperature settings.

Tank-style RV water heaters operate by filling a small tank with cold water from your RV's fresh water system. Once the tank is full, the unit uses either a propane burner, an electric heating element, or both to heat the water to a preset temperature. A thermostat monitors the water temperature and cycles the heat source on and off to maintain it.

When you open a hot water tap, the system draws hot water from the top of the tank while simultaneously refilling it with cold water at the bottom. This process continues until the hot water is depleted, at which point you’ll need to wait for the tank to reheat. Because of this, tank models aren't always the best option for longer showers and heavier water use unless you’re willing to wait between uses.

Tankless RV water heaters, like the Furrion tankless model, work quite differently. Instead of storing hot water, they heat it on demand. When you turn on a hot water tap, a flow sensor detects the movement of water and activates the burner or heating element. The water passes through a heat exchanger, where it is rapidly heated to your desired temperature before exiting the faucet.

This process happens almost instantly, providing continuous hot water as long as there’s a water supply and fuel source. Because there’s no tank to refill or reheat, tankless systems are far more efficient and eliminate the need to ration hot water. They also tend to be more compact and lightweight, making them ideal for RVers who want to save space and reduce energy consumption.

Modern RV water heaters — especially tankless models — come equipped with digital control panels, temperature sensors, and safety shut-off mechanisms. These features help prevent overheating, protect against dry firing (running the heater without water), and allow you to fine-tune your water temperature for comfort and efficiency.

Choosing between a tank and a tankless RV water heater depends on your travel habits, energy preferences, and how much hot water you typically use. Both systems have their strengths, and understanding the differences can help you make the best choice for your RV lifestyle.

Tank water heaters are a tried-and-true option for many RVers. They’re relatively simple to operate, widely available, and often come pre-installed in many RVs. If you’re a weekend camper or someone who uses hot water sparingly, a tank model may be all you need. These systems are great for short showers, washing dishes, and basic daily use. They’re also a good fit if you frequently camp at sites with full hookups, where you can rely on electric power to heat your water.

However, tank heaters do have limitations. Once the hot water in the tank is used up, you’ll need to wait for it to refill and reheat, which can be inconvenient, especially if multiple people are using the water back-to-back. They also tend to use more energy overall, since they maintain a constant water temperature even when not in use.

If you’re looking for continuous hot water, better energy efficiency, and a more modern solution, a tankless water heater is a smart upgrade. These systems heat water on demand, meaning you’ll never run out of hot water. This is perfect for families, full-time RVers, or anyone who enjoys longer showers. Because they only operate when water is flowing, they use less energy and eliminate standby heat loss.

Tankless models are also more compact, freeing up valuable storage space in your RV. They’re especially beneficial for boondockers or off-grid travelers who want to conserve propane and power. The Furrion tankless water heater, for example, is designed specifically for RVs and offers fast ignition, smart temperature control, and built-in safety features — all in a sleek, space-saving design.

In short, if you value efficiency, convenience, and comfort, a tankless system is likely the better choice. But if you’re sticking to short trips and light water use, a traditional tank heater can still serve you well.

Most RVs come with a factory-installed water heater, but upgrading is possible. When considering a switch:

• Check space and venting requirements
• Ensure compatibility with your RV’s plumbing and electrical systems
• Look for models designed specifically for RVs, like Furrion’s tankless units

Installing or upgrading an RV water heater — especially switching from a traditional tank model to a tankless system — can be a rewarding upgrade, but it’s important to understand the process and ensure compatibility with your RV. Many owners choose to upgrade for better performance, energy efficiency, or convenience. Before starting, you’ll want to check the dimensions of your existing water heater compartment, venting setup, and power source (propane, electric, or both). Tankless models like the Furrion tankless water heater are designed to fit standard RV cutouts and often come with retrofit kits to simplify the process.

While professional installation is recommended for those unfamiliar with RV plumbing or electrical systems, many experienced DIYers can handle the job with the right tools and preparation. Here’s a high-level overview of what the installation process typically involves:

1. Turn off all power and water sources
   Disconnect propane, electricity, and water lines to ensure safety.
2. Remove the old water heater
   Unscrew the mounting hardware, disconnect plumbing and wiring, and carefully slide the unit out.
3. Prepare the opening
   Clean the compartment, check for any damage, and ensure the new unit will fit properly.
4. Install the new water heater
   Slide the new unit into place, secure it with mounting brackets, and connect the water lines.
5. Connect power and fuel
   Reconnect propane and / or electrical wiring according to the manufacturer’s instructions.
6. Seal and insulate
   Use RV-grade sealant around the exterior flange to prevent leaks and drafts.
7. Test the system
   Turn on water and power, check for leaks, and test hot water flow and temperature settings.
8. Configure settings (for tankless models)
   Use the digital control panel to set your desired temperature and activate safety features.

Learn more about the process with our comprehensive water heater replacement guide.

Proper maintenance is key to keeping your RV water heater running efficiently and extending its lifespan. Whether you have a tank or tankless model, a little routine care goes a long way in preventing breakdowns and ensuring consistent hot water on the road. Here are a few key tips to remember:

1. Flush the tank regularly to remove sediment (clean and descale your tankless model)
2. Inspect the anode rod (for tank models) and replace as needed
3. Winterize your system before cold weather
4. Check for leaks and corrosion

Tankless models require less maintenance but should still be inspected seasonally. Whichever model you have, before hitting the road, run a quick test of your water heater. Make sure it ignites properly (for propane models), heats water to the correct temperature, and doesn’t trigger any error codes. This simple check can save you from cold showers at the campsite.

Learn about troubleshooting your RV water heater

If you’ve ever run out of hot water mid-shower in your RV, you already know one of the biggest drawbacks of traditional tank-style water heaters. That’s where tankless water heaters shine. These systems provide hot water on demand, meaning you’ll never have to wait for a tank to refill or reheat. They’re also more energy-efficient, since they only heat water when you need it — no more wasting propane or electricity keeping a tank warm all day. Plus, their compact design frees up valuable space in your RV, making them ideal for both small campers and large motorhomes.

Tankless water heaters are especially appealing for full-time RVers, families, or anyone who values convenience and comfort on the road. Whether you're washing dishes, taking back-to-back showers, or cleaning up after a long day of hiking, a tankless system ensures you always have hot water when you need it.