Best Outdoor Tankless Water Heater – (Reviews & Guide 2020)

Imagine going on a cross-country family trip with an RV. How awesome will it be to have endless hot water for all your needs? That can easily be achieved with an affordable one-time investment in a portable outdoor tankless water heater.

To find the best outdoor tankless water heater, you will have to do thorough research as there are a lot of options, models, and brands available on the market.

Tankless water heaters are more advanced technologically and are way more effective and convenient than water heaters with tanks. If you’re wondering whether it’s worth upgrading to a tankless heater, the short answer is ‘Yes.’

Keep reading our guide, and you’ll see why…

In the meantime, we have prepared some outdoor tankless water heater reviews to ease your decision-making process.

Best Outdoor Tankless Water Heater Comparison Chart

Rinnai V Series HE Tankless Hot Water Heater

Rinnai V Series HE Tankless Hot Water Heater

  • Price: $$$$
  • Dimensions: 27 x 18.5 x 11.8”
  • Flow Rate: 5.3 GPM
  • Gas Type: Natural Gas
  • Weight: 33 pounds
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GASLAND Tankless Water Heater

GASLAND Tankless Water Heater

  • Price: $
  • Dimensions: 11.8 x 6.1 x 17.3”
  • Flow Rate: 1.58 GPM
  • Gas Type: Propane
  • Weight: 15.65 pounds
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Rinnai V65IN Tankless Water Heater

Rinnai V65IN Tankless Water Heater

  • Price: $$$$$
  • Dimensions: 13.9 x 8.8 x 23.6”
  • Flow Rate: 6.5 GPM
  • Gas Type: Natural Gas
  • Weight: 49.4 pounds
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Camplux Outdoor Propane Gas Tankless Water Heater

Camplux Outdoor Propane Gas Tankless Water Heater

  • Price: $$$
  • Dimensions: 17.3 x 7.9 x 27.6”
  • Flow Rate: 4.22 GPM
  • Gas Type: Propane
  • Weight: 36 pounds
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Best Outdoor Tankless Water Heater – Editors’ Picks

The reviews are in no particular order for the products.

1. Rinnai V Series HE Tankless Hot Water Heater

Rinnai V Series HE Tankless Hot Water HeaterThis water heater is from the well-known brand Rinnai. This model is for outdoor installation only. It uses natural gas ignition, but there’s also a propane version of the same model.

This water heater can reach up to 5.3 gallons of hot water per minute. The unit requires electricity to work, so make sure you install it next to a power outlet. It can also be hard-wired into the electrical system.

However, if there’s no power outlet and hard wiring isn’t an option, you will need to purchase a power cord as there isn’t one included in the package. You may need to insulate the pipes well if you live in an area with low temperatures.

If you aren’t happy with the water pressure and flow in your home, you may need to remove the water flow restrictor from the showerhead. The unit has anti-freeze protection that works down to 30 degrees.


  • This heater is with low NOx which means that it has lower emission and is more fuel-efficient compared to conventional heaters.
  • The heater has a Wi-Fi model and can be controlled from a distance with a mobile app.
  • It has a factory warranty – 120 months for heat exchanger and 60 months for parts.
  • Cuts your monthly energy bill in half.
  • The unit comes with remote control.


  • Shortly after installation, error codes may appear.
  • You need to buy additional items to install it, like the shut-off valve.

2. GASLAND Tankless Water Heater

GASLAND Tankless Water HeaterThe GASLAND Outdoors BE158 outdoor tankless water heater needs only two batteries to work. It is compact, with a size of 11.8 x 6.1 x 17.3 inches. The size and the lightweight make the heater suitable for RVs and camping. This unit provides 1.58 gallons of hot water per minute.

This water heater isn’t suitable for areas with water pressure below 2.5 PSI. You will need a water pump to increase it. However, if you cannot provide this much pressure, the heater won’t ignite and work. It uses propane gas to heat the water, and this makes it heat very fast.

So fast, you even have to be ready to adjust the temperature when you turn it on, so you don’t get burned. This tankless water heater is great for your backyard, but it isn’t suitable for altitude over 3300 feet.


  • Heats water quickly, with no pre-heating and waiting necessary.
  • This heater has fully adjustable heat and water flow.
  • The unit comes with a handheld showerhead.
  • You can use it indoors – in an RV or a cabin – as long as they are well-ventilated.


  • You may have some problems understanding instructions as they are vague.
  • The hot water starts too hot at first, so you must be careful.

3. Rinnai V65IN Tankless Water Heater

Rinnai V65IN Tankless Water HeaterThis tankless water heater is from Rinnai, the V65In model, which uses natural gas. Besides buying it, you will also need to purchase a termination valve kit and an isolation valve kit for outdoor installation. The vent kit is also sold separately. The ventilation pipe size is 3 ½ inches and you can use a pre-existing hole with the same size.

The installation may require a professional plumber and buying additional piping and fittings to install it. DIY installation is possible if you have some experience and knowledge.  For homes with soft water, it requires minimal maintenance. It makes a whirring sound when used. It’s not a big problem but needs to be considered for its location.

The advertised 6.6 GPM is true for places where the water is at an average temperature. If you live in a place with cold water or well water, the most you can get is around 3.3 GPM. Since this heater doesn’t have anti-freeze protection, it should be drained when it’s not being used in the winter.


  • This product comes with standard Rinnai warranty – 10 years for the heat exchanger, 5 years on everything else.
  • The heater can be used on a mobile home.
  • With good water pressure, two or more showers can be used simultaneously.
  • Even the lowest flow rate of 3.3 GPM is very good compared to most units that provide only 2.5 GPM.


  • It heats a bit slowly, especially with a well or cold water source.

4. Camplux Outdoor Propane Gas Tankless Water Heater

Camplux Outdoor Propane Gas Tankless Water HeaterThe Camplux 16L Outdoor 4.22 GPM Gas Tankless Water Heater is super quick at warming water and reaching up to 150 degrees. This heater is the size of a carry-on suitcase but a bit heavier, and when hooked on a wall, it becomes bulky. It is not as portable as other water heaters. You cannot convert it to using natural gas.

The heater requires two alkaline batteries that can last up to three months, depending on the use.

It is made for outdoor installation, but if you decide on setting it up indoors, you will need to add a vent pipe. You can set it up in an RV, outdoor, or indoor of your home. For an outdoor installation, it will need protection from rain, keep that in mind.

The installation is straightforward, there’s nothing special that requires a professional plumber. When you don’t use it, it shuts off. When you use it, it heats the water fast enough. Overall, it’s an efficient product at a reasonable price. With strong water pressure in your home, this unit can supply multiple fixtures with hot water simultaneously. The minimum required water pressure is 3.6 PSI.


  • This outdoor water heater has anti-freezing and overheating protection.
  • Everything you need, except for the batteries, is included in the package.
  • This unit comes with a showerhead.
  • The unit has flame failure protection.
  • The 4.22 gallons per minute are enough to fill a hot tub fast.


  • This model’s shower head hose is a bit short and not the greatest quality.

What is a Tankless Water Heater?

Outdoor Tankless Water Heater ReviewsA tankless water heater is a compact option for indoor and outdoor use that provides a steady flow of hot water when you need it. There’s no waiting for a re-heating process. They use either natural or propane gas to heat the water. The models that are made for residential use are powered by electricity. There are two types – condensing and non-condensing water heaters. We’ve explained them below, so keep reading.

Some options are called “portable” and can be installed on different RVs – caravans, truck campers, motorhomes, campervans, etc. These types of outdoor tankless water heaters are powered by batteries. If you’re interested in reading more about the electric water heaters, be sure to check out our whole house electric tankless water heater reviews.

Benefits & Drawbacks of Outdoor Tankless Water Heaters


  • No additional installation on venting kits, saving you time and money.
  • Saves space inside of the house. If you don’t have space inside your home, then it’s the perfect option.
  • The noise doesn’t annoy you. All water heaters make some noise while working. An indoor heater can be annoying to listen to, but an outdoor one you cannot hear.
  • Easy and convenient for quick summer showers for your kids and pets. Speaking of which, check out our buying guide on the best kids shower heads to see which are the features to look for when buying such a product.
  • Provide an endless supply of hot water, unlike its counterpart – the water heaters with tanks.
  • Some models can be controlled with WI-FI, allowing you to turn in on even before you come home from work.


  • Might need some protection and shields installed if you live in an area with winds, snow, rain, low temperatures.
  • Depending on where you install it, there’s a risk of vandalism. Be careful when choosing the place to mount it.

What to Consider When Choosing an Outdoor Tankless Water Heater

Best Outdoor Tankless Water Heater

To find the best outdoor tankless water heater you need to take into account the following conditions:

  • The size of your home and your family’s hot water needs. It is important to take into account how many faucets/showers you have, and how much hot water you use in a peak hour. Then choose a product that will deal with the capacity of hot water your family needs.
  • The power source is important as gas water heaters cut down your electrical bill. They are also almost equally efficient regardless of the season and temperatures, whereas an electrical one’s performance decreases when it’s cold. Also, make sure to get a heater that uses the same gas type (natural or propane) that your home has access to. You can calculate the water BTUs that your water heater would need and compare products.
  • The warranty should be taken into account. In the best-case scenario, the products have up to 10 years warranty on the heater, and 5 years on the separate parts.
  • The price affects quality. With everything in mind, also find one that doesn’t break the bank. The good thing about outdoor water heaters is that they require fewer additional parts, fittings, and piping, so you can splurge more on the quality or the size of the heater itself.
  • The size matters for the location of the heater. They all have the same shape and design, but the sizes are different. You should have an idea about where you can install it so you can measure if there’s enough space. Keep in mind that there should be at least 10-15 inches from other appliances, from the floor, and from the ceiling.

How Much Does an Outdoor Tankless Water Heater Cost?

Tankless water heaters are more expensive than water heaters with tanks. When compared to indoor heaters, they may be more affordable as they don’t require additional ventilation setup.

The price range varies a lot, so keep in mind that the price will affect the capacity and materials of the water heater. For more energy-efficient shower products, check out BeyondShower’s home page and compare products. You will find accessories and other shower products to improve your shower time.

Easy Installation for Portable Outdoor Tankless Water Heaters

Most outdoor water heaters aren’t difficult to install, as they do not require additional fittings and piping for proper ventilation. However, if you feel uncertain about doing it yourself, you can always pay a professional to do it.

  1. First, securely hang your tankless water heater using fixing kits.
  2. Insert two batteries (as required by the model) and check if the polarity is correct.
  3. Connect the gas inlet with a supplied gas regulator (natural or propane gas).
  4. Connect water inlet with a standard hose.
  5. Connect the water outlet with a shower hose and shower head provided.
  6. Adjust the water and gas knobs to the temperature you want.
  7. Enjoy the endless hot water.

Comparisons between Condensing and Non-condensing Water Heaters

There are two options for tankless water heaters, non-condensing, and condensing heaters.

The condensing systems are 10% more efficient than non-condensing ones. Read on to see their differences and why one type is more – efficient than the other.

Advantages of non-condensing heaters

  • Fewer parts needed are used in the heater, making installation easier;
  • Because of the fewer parts, fewer things that can go wrong with it;
  • Costs less to install;
  • Minimum maintenance is required;
  • You don’t have to worry about disposal of condensate.

For remodeling or retrofitting, non-condensing water heaters will be better to use. No additional work or maintenance is required.

Both types can be installed outdoors or indoors, depending on the model. Those for an outside mount are good for warm climates.

The indoor option requires a stainless steel vent pipe because the pipe may get condensation and stainless steel doesn’t rust. The gas also gets heated to about 300 degrees meaning that more durable and therefore expensive pipes and parts are needed.

Condensing water heaters have pipes where water collects and condensates. This is the reason these water heaters are more efficient. However, with that, they require more maintenance and have to be drained regularly.

Advantages of condensing heaters

  • You can use PVC pipes as the gasses are only heated to about 100 degrees;
  • These can be installed anywhere in closed spaces and don’t require an open flue to the outside for ventilation;
  • The PVC pipes can be cheaper than stainless steel and easily insulated from the air;
  • Condensing heaters are with up to 10% more efficient than non-condensing;

Condensing water heaters are suitable to install if you’re rebuilding your plumbing system. This way you can plan and install a drain or a drainage system to deal with the condensation. If you’re installing a condensing water heater outdoors, you must also buy and attach a neutralizer to keep high pH levels of the condensed water. The pH levels are between 3 and 5 which make the condensed water acidic and kill grass and plants if dumped on them.

These condensing water heaters might need time to catch up on the savings, but you will feel them at some point.

Do Outdoor Tankless Water Heaters Need Maintenance?

Yes, just like any other household appliance. Depending on the model and on the water in your home, the required maintenance is different. For houses with hard water, it is recommended to flush the heater with vinegar at least once a year. Maybe more if the water is very hard and causes problems to the heater often.

Hire a professional plumber to clean water and air filters and inspect the burner. This should be done annually if you want to be strict with the water heater maintenance.

The capacity of Tankless Water Heaters

The input temperature is important for the water flow, the power required, and for how many faucets or showers can be used simultaneously.

Depending on the initial temperature of the water, the required amount of work from the water heater is different. If the water that gets in the heater is 50-60 degrees, it will use less energy to heat it up to a maximum of 120. If the initial water is coming from a well and is around 35-40 degrees, the heater will use more energy to heat it up. Respectively, the colder the water that gets in it, the more power it uses. So a unit that works well in the south won’t perform as good in the north.

When choosing a tankless water heater, get one with higher GPM than you need, just to be on the safe side. Sizing a tankless water heater is based on some simple calculations.

Safety Tips for Using Gas Outdoors Tankless Water Heater

Natural gas is flammable, so you MUST take some precautious measures when having a water heater that uses propane or natural gas to work:

  1. Install it properly and according to instructionсs, so there are no gas leaks.
  2. Keep the water heater at a safe distance from other appliances.
  3. Do not keep or put other flammable objects near the water heater.
  4. Close the gas valve after using the water heater or when you’re away from home for a long period of time.

If you use this unit on an RV and it’s an outdoor model, you should insulate it well to protect it from freezing. Moreover, it would be best if you can uninstall the heater and bring it inside when you’re not using it.

FAQ About Outdoors Tankless Water Heater

Q: Can a new model be installed in the same place an old water heater was?

A: If you’re replacing the old one with a new model from the same brand, it is possible that the existing conditions can be used for a new model. If you’re buying another brand, a different size, or a model with different requirements, it may not be an option to use the same space.

Q: Can I convert my water heater from LP to natural gas or the other way around?

A: Some models can be converted with an additional part, others cannot.

Q: Should all outdoor units be covered in the winter or when it rains?

A: It is preferable to shield the water heater from harsh weather. Snow, rain, hail, and very low temperatures can have an impact on its performance or even damage it. For example, pipes that are also outdoors should be insulated before the winter to prevent them from freezing and breaking.

Q: What are some advantages of using a tankless water heater over a standard storage-type heater?

A: The biggest advantage is that tankless water heaters can provide an endless supply of hot water, while a heating tank runs out of hot water and you have to wait. Tankless water heaters are more durable because since water isn’t stored inside it doesn’t have time to do any damages to the heater. Such units are generally smaller exactly because they don’t store water. They are also energy-efficient because they don’t have to pre-heat stored water.

Wrap up

We have to end our guide here. We hope that our outdoor tankless water heater reviews and our guide helped you understand these products and their features better. With this much information about the types of outdoor water heaters and their features, you now have everything you need to make an informed decision.

If you’re planning on renovating your house and wish to install such a unit outside, you’ll find the best outdoor tankless water heater to satisfy your needs.

Our team thanks you for choosing our guide for your research. We are always open for your honest feedback. We hope we answered the questions you had about outdoor tankless water heaters. If we didn’t, don’t hesitate to leave us a question below.

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