Skip to Content

5 Best Portable Water Heaters

5 Best Portable Water Heaters

The fondest memory of childhood camping trips is probably the early morning swim or bath in a chilly stream.

Now, today’s outdoor trips are being reshaped by the possibility of warm showers in the middle of nowhere.

The emergence of portable water heaters has eliminated the need for that tortuous old morning routine. You can look forward to outdoor activities again with the assurance that you will not have to sacrifice all the luxuries you enjoy at home!

Buying Guide: 4 Best Portable Hot Water Heaters

Water heaters are a money-saving and energy-efficient household staple that makes life infinitely better. This section contains an impartial analysis of the top-performing heater brands that you should consider when you are shopping for a portable water heater.

Eccotemp L5 Portable Outdoor Tankless Water Heater

Eccotemp L5 Portable Outdoor Tankless Water Heater


The Eccotemp L5 heater was designed to clean adventurous people, kids, and pets! It can also be used to wash a vehicle or a boat.

If you find yourself off-grid with no electricity, the “D” battery backup will ensure that you still get a hot bath.

Key Features of Eccotemp L5 Portable Water Heater

  • Designed for outdoor use only
  • Comes with an on/off shower head and a stainless steel shower hose
  • Packaging includes a CSA regulator that can be used with a 20 lb (9.07 kg) propane tank
  • Features water-controlled igniting. Water pressure from 20 PSI automatically switches on the ignition circuit. Max pressure is 80 PSI
  • Water temperature is controlled manually
  • Safety shut-off if water runs for more than 20 minutes
  • It will provide 18 hours of hot water with a 20 lb (9.07 kg) propane tank
  • It uses 375,000 BTU of propane to heat water
  • Maximum flow rate is 1.4 gallons (5.3 L) per minute
  • 30 to 35 temperature increase at 1.4 gallons per minute
  • Dimensions are 11.4 x 4.8 x 15.9 inches
  • Weight 12 lbs (5.44 kg)
  • ½-inch national pipe taper (NPT) fitting

The Good

  • It provides instant hot water
  • Energy efficient, using very little propane for every shower session
  • Easy to set up and operate
  • Easy to adjust water pressure and temperature

The Bad

  • Even though it is designed for outdoor use, windy conditions put out the flame
  • It is not safe for use in enclosed spaces

If there ever was an appliance described as “outgoing,” it would be the Eccotemp L5. This water heater is becoming a common fixture in RVs, cabins, and even outside camping tents.


Rheem 240V Heating Chamber RTEX-08 Residential Tankless Water Heater


Rheem Manufacturing has been in the water heating business since 1925. With their wealth of experience, the Rheem company manufactured an eco-friendly, digital water heater. The RTEX-08 claims to operate at the energy efficiency of 99.8%.

This is the best performance yet by a residential water heater on the market.

Key Features

  • The Rheem heater has an LED display, showing the temperature controlled by a thermostat
  • Once you choose your desired water heat, the heater will automatically adjust when it rises or falls below the baseline
  • The external temperature controls adjust the heat in increments of 1
  • It boasts a whopping 99.8% energy efficiency by reducing the water and energy consumption
  • The water-saving showerhead has an output of 1.5 gallons (5.68 L) per minute
  • The heater immersion is made of durable copper
  • Packaging comes with everything that is needed to install the heater, including an electric cable, water connections, and NPT adapters
  • Unlike other water heaters, the Rheem does not use batteries
  • Dimensions are 4 × 9 × 13 inches (33.02 cm)
  • The heater is lightweight at 6 lbs (2.72 kg)

The Good

  • Installing this heater is doable as a DIY project with a detailed installation manual included
  • Even though it uses electricity only, it is so efficient that it consumes significantly less power than conventional water heaters
  • Instant hot water output
  • Very small and light, so it can be installed anywhere within the house

The Bad

  • It is a single-point use water heater. If you need hot water at multiple points in your home, you need to install more than one RTEX-08 water heaters
  • It needs a constant supply of electricity. In case of a blackout, you will not be able to get hot water

This heater is a big step towards environmental conservation. Its high energy efficiency rating and zero emissions are quite the find. Enjoy endless hot water use unencumbered with guilt about the environmental consequences of this heater.


Rheem 240V 3 Heating Chambers RTEX-24 Residential Tankless Water Heater


The Rheem RTEX-24 is another model in the series of the Rheem 240V. If you prefer to have an electric tankless heater as opposed to gas, then you should consider this water heater.

This sleek water heater was designed for home use for large households.

Like the RTEX-08 the RTEX-24 has an efficiency rating of 99.8%.

There are, however, a few things you need to know before you settle for buying this 3-chamber hot water unit.

Key Features

  • The immersion heating element is made of copper, as can be expected, it heats water without the risk of corrosion. The top is made of threaded brass for durability and easy replacement.
  • Unlimited hot water at the precise temperature you set on the digital display.
  • Despite its capacity to serve large families, it is still compact and elegantly-designed
  • It comes with a self-modulation feature that adjusts the temperature of the water to meet hot water demands during multiple uses
  • The output rate is at 1.58 GPM (5.98 L) on a water-saving showerhead and 2.0 GPM (7.57 l) on standard showerheads
  • It Requires ¾ inch NPT plumbing connections
  • A flow rate of up to 5.9 GPM
  • The dimensions of the heater are 4 × 18 × 19 inches
  • The heater weighs 17.8 lb (8.07 kg)

The Good

  • You get a complete installation guide that makes for a great DIY project. Setting up the Rheem RTEX-24 is a simple process of following the highly detailed manual
  • At only 17.8 lb (8.07 kg), the water heater is easy to haul and install anywhere you choose within your home
  • Digital temperature display and thermostat control
  • Self-modulation makes sure everyone gets water that’s hot enough for their needs
  • This is the ideal heater for showering during the winter months. The water temperature can heat up to 140℉The heating elements are made of durable materials that do not corrode easily
  • It’s easy to adjust the temperature

The Bad

  • The wiring process during installation can cost a pretty penny since you are buying some electrical components separately
  • It consumes more energy to heat water during winter months
  • The temperature of the water may fluctuate during winter as well

Even though the heater is recommended for big households, smaller households can install it too. Besides the shower, it can service washing machines, sinks, dishwashers, and bathtubs.


Rheem 240V 4 Heating Chambers RTEX-36 Residential Tankless Water Heater

Rheem 240V 4 Heating Chambers RTEX-36 Residential Tankless Water Heater


Rheem RTX-36 comes with four heating chambers alongside the uniform features of the RTEX-28 and RTEX-08. It is the largest model in this series.

Key Features

  • It Requires ¾-inch NPT plumbing connections
  • A flow rate of up to 8.8 GPM
  • The dimensions of the heater are 4 × 22 × 19 inches
  • The heater weighs 22.7 lbs (10.3 kg)
  • The heater can provide hot water for two to three outlets simultaneously
  • External temperature control that adjusts the temperature in increments of 1℉
  • The four immersion heating elements are made of copper and threaded at the top and sealed with brass to last longer
  • Unlimited hot water at the precise temperature you set on the digital display.
  • Amperage is 150 Amps
  • It comes with a self-modulation feature that adjusts the temperature of the water to meet simultaneous hot water demands
  • The maximum output rate is high at 8.0 GPM (30.28 L)
  • The digital display shows the outlet temperature

 The Good

  • You can get hot water from multiple points of use at the same time
  • The compact design means that it takes little space
  • Point of use installation eliminates the wait for the water to get hot
  • Great for big families
  • Self-modulation and thermostat controls are great features
  • Unlimited supply of hot water
  • Despite the size, it is thoroughly energy-saving

The Bad

  • The installation of this unit might be its biggest disadvantage. You will probably have to hire a plumber and an electrician
  • The price is on the higher side


Choosing the Best Water Heater for Your Needs

Best for Outdoor Camping

The Eccotemp L5 Portable Outdoor water heater was specifically optimized for outdoor use only. In addition, it is meant to be installed only when needed. Installing it as a permanent fixture is highly discouraged.

For these reasons, Eccotemp makes the perfect heater for people who are constantly on the move.

The best camping sites have endorsed it as an ideal camping accessory.

You can also try installing the Rheem 240V series in cabins and mobile homes

Heater for Winter

Rheem 240V 3 Heating Chambers RTEX-24 and the Rheem RTX-36 four chambers are great appliances for your winter needs. Their max temperatures go up to 140 and 170°F, respectively.

 Most Eco-friendly/Energy Efficient

Rheem RTEX-13 Residential Tankless Water Heater is the best energy-saver for indoor use. Its efficiency score is at a near-perfect 99.8%. It is hailed as one of the most reliable and user-friendly water heater models on the market.

Best for Indoor Use

This is the reason the entire Rheem 240V residential series was made.

They are safe and convenient to use indoors with big water and energy-saving gains for households that have installed them.

FAQ About Tankless Water Heaters

1.      How much can I save with a tankless water heater?

You will be able to save from 5% to 69% of your bill, depending on the make of the water heater you are using.

2.      Will a high altitude affect the performance of my gas water heater?

This is true for gas water heaters. They lose a bit of their efficiency the higher they are placed.

3.      Is one tankless heater enough to heat the water needed for my entire home?

Yes, some models support multiple outlet use simultaneously and will provide enough hot water as needed. It is important to know which models support that functionality.

4.  How often should I service my tankless water heater?

Most manufacturers recommend that you carry out maintenance on water heaters once a year.

Rheem is among the manufacturers suggesting yearly maintenance – and even has a comprehensive lime and scale flushing guide to help you do it yourself.

5.  How do tankless water heaters heat water instantly?

When you open a shower/sink faucet, the flow of water triggers the heater to turn on. Most tankless heaters come with water flow sensors that activate rapid heating of the water as it passes through.

6.  How long do tankless water heaters last?

Tankless water heaters last for 20 years. This is 5 to 10 years longer than the standard storage heater tanks.


This has been our comprehensive buying guide for the most affordable and highly rated water heaters available on the market. We hope it fully addressed all your questions about your portable heating needs.