No matter whether you want the best tankless water heater for an RV or the best mini-tank, these top picks are sure to please and will even work in cabins and other small structures.
RV Tankless Water Heater Reviews
1) Marey GA10LP (Best Tankless Water Heater for RV)
When you’re looking for the best tankless water heater for an RV, camping trailer, or small home, the GA10LP is hard to beat. It has a compact design and is able to save as much as 60 percent on your water heating bills.
While this water heater runs off liquid propane, a natural gas version is also available.
Thanks to the ability to control both water and gas flow, the 10L unit is able to provide up to 2.7 gallons per minute at 115 degrees. It can service up to three points throughout the structure at the temperature you desire, even when there’s low water pressure.
Another attractive feature of this water heater is its power source. Unlike most on-demand heaters, the GA10LP runs off of two D-cell batteries instead of an electrical connection so it’s perfect for off-the-grid use (propane gas is still required).
The entire, easy-to-install unit weighs a mere 21 pounds and is rust-proof and can be connected to your existing exhaust system.
While easy to install, it’s important to follow all instructions carefully. It may also take a little fiddling to find the perfect setting. This unit is designed more for stationary use, so you may have to tighten some of the leads after a trip.
Designed specifically for RVs and other small structures, this wall-mounted propane unit requires only half the space and propane used by traditional 10-gallon tank (see also ‘The Best Stands For 10-Gallon Fish Tanks‘) models.
Approximately 940 gallons of hot water can be produced with a single 20lb propane tank, while the unit itself weighs a mere 32lbs. The unit also uses only 1.5 amps of power under normal operation and 3 amps when set for cold weather protection.
The RV-550 features automatic gas modulation, allowing it to self-adjust gas usage by monitoring water flow rate and temperature. As a result, you’ll get a more consistent temperature without being affected by the weather outside.
Providing 55,000 BTUs of water output, this model’s one of the most powerful on the market. In winter, the unit will automatically protect itself from freezing as long as it has gas and power.
This is a highly efficient and easy-to-use water heater. However, a few users have had some trouble that have been traced back to the LP regulator and use of flow restrictors.
Checking these two points should fix most problems, and the company offers great customer support in the event there are any further issues.
This on-demand water heater provides 3.6GPM, making it a great choice for both RVs and small homes. Its easy to read digital temperature display makes manual adjustments a breeze, and the unit is able to detect and activate with a GPM flow as little as 0.65.
The unit is both quiet and space-saving, making it perfect for point-of-use when you want more than one for increased output.
It’s important to note that this unit runs similarly to a restrictor and the temperature setting knobs actually adjust the flow rate.
Thus, the higher you set the water temperature knob, the lower the maximum flow rate will be, whereas lower settings will require a higher minimum flow before activating but can provide a higher flow capacity. Set this to a level that best suits your needs, then set the gas knob to an acceptable temperature.
Note also that this unit is not well insulated against freezing temperatures and should be drained completely if not being used in cold temperatures. Several users have reported their unused unit cracking or exploding after being exposed to below freezing temperatures without being drained.
Unlike our previous entries, this lightweight tankless water heater is actually portable. As a result, it has both advantages and disadvantages over the others.
The built-in anti-freezing and overheat protection protect your family from the risk of explosion or burns. Meanwhile, it’s capable of a maximum 41,000 BTU per hour while still providing an 11.5 percent in energy savings.
It’s important to note that this portable tankless water heater is best suited as a point-of-use and not a replacement for your RV water heater. It activates when water pressure hits 2.5 PSI and can deliver 1.8 gallons per minute.
This makes it perfect for the shower, leaving your main hot water heater free to support the kitchen and bathroom sink without interrupting your hot water supply. Best of all, it runs on two D batteries, so there’s no need for an electrical hookup.
This heater is easy to install wherever you are, so long as you don’t overtighten the connections. The temperature settings use Celsius instead of Fahrenheit, so be careful when choosing the temperature.
Also, keep in mind that teflon tape around the gas connections is important, since this model was designed with mobility in mind and may develop leaks when connected during transit.
5) Suburban SW6DE (Best Mini-Tank Water Heater for RV)
This mini-tank RV water heater has a porcelain-lined, 6 gallon capacity steel tank capable of providing all the hot water you’ll need. It can run on electric or propane and uses direct spark ignition instead of a pilot light for better cost efficiency.
The tank’s solid one-piece shell protects it from the elements, while the replaceable anode rod protects the interior. It’s arguably the best mini-tank RV water heater you can buy.
There are very few complaints about this 12,000 BTU model. However, it should be noted that several Suburban water heater models were recalled in Australia in 2019 due to a carbon monoxide leak.
The SW6DE was not among those models recalled, nor were there recalls in other countries and the issue seemed to be related to use in Australian-built RVs.
This easy-to-install mini-tank features aluminum-clad construction and a 6-gallon capacity. One of its biggest selling points is the ability to service 95 percent of its parts from outside your RV.
Direct spark ignition and temperature limit switch, and pressure relief make this heater both safe and cost-effective. It even boasts an impressive 11.6 gallons per hour recovery rate.
Its 8,800 BTU input allows you to have hot water within 30 minutes of installation. However, be warned that this model may not have all of the fittings you need and refurbished units are prone to component failure.
Rounding off our list is a point-of-use electric mini-tank boasting 98 percent thermal efficiency and the ability to be installed either vertically or horizontally. With its compact size, it’s easy to hide.
It has a temperature range of 65 to 145 degrees and can recover approximately 6.8 gallons per hour at 90 degrees, responding to a water PSI as low as 150. This Bosch is a great option for your camping trailer or as a point of use water heater under your home’s kitchen sink.
Three capacity options are available: the ES2.5 (2.5 gallon), ES4 (4 gallon), and ES7 (7 gallon). The tank features glass lining and a magnesium anode rod, and is covered by a 6-year warranty and one-year parts warranty.
There are a few important steps the manual omits that will prevent the majority of problems users have encountered. First, make sure you use a water heater connection hose with flat rubber gaskets on both connections. Standard NPT fittings may result in a poor seal.
Second, all connections should be pressure tested before connecting the unit to power. This will let you check for potential input leaks. When the unit is installed vertically, any such leak will run into the electrical connection box.
And finally, make sure the pressure relief valve is connected properly, as failure to properly connect may result in moisture that can mimic a leak.
RV Tankless Water Heater Buying Guide
There are a lot of factors to consider when shopping for a home water heater, and your RV’s needs are no different. Weigh the following factors before choosing a model for the best possible fit.
Electric vs Gas
Electric water heaters are often the go-to for homes, but that might not hold true for an RV. Think about where you’re likely to set up and whether you already use propane for other on-board applications (such as a gas range).
Some models may use batteries, completely freeing you from the need of a power source, but others will require an electrical connection whether you use propane or electric for fuel.
Tankless vs Mini-Tank
Tankless models are highly efficient and take up less space. However, the amount of water they can produce at one time is more limited.
Mini-tanks require a little more space, but are also able to store a small quantity of hot water to boost output. They heat much faster than a normal tank model for your home. Choose the one which best suits your output and space needs.
This factor affects mainly mini-tank models, as the heating capacity of tankless models is the same as their flow capacity. For most basic RV needs, a 6-gallon tank will be sufficient if the recovery rate per hour is around double the capacity.
Smaller tanks heat water more quickly, so it’s less apparent when you run out than your 30-gallon home model running out during a long shower.
Families who use more hot water may require a larger tank or the addition of a tankless heater for on-demand service to a specific area.
Water Usage and Flow Capacity
The flow capacity of a tankless water heater (see also ‘Marey GA10LP In-Depth Review For 2021‘) is based upon how much the unit can put out at a given time. This number affects how many taps can be used simultaneously before the heater has trouble keeping up. Knowing how much you may potentially need at a given time helps prevent temperature drops.
Below are a list of the average flow rates for different tap types to give you a better idea of the flow capacity needed for your family’s needs:
|Average Gallons Per Minute (GPM)
|Sink Faucet (no aerator)
|Sink Faucet (w/ low flow aerator)
|Shower Head (standard flow)
|Shower Head (low flow)
|Bathtub Faucet (5-axle RVs and larger)