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10 Best Boat Hot Water Heaters And Their Reviews For 2022

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Tim Rhodes

So you have a boat, you might need a boat hot water heater for that.

You want to go sail out into the waters but are worried about having hot water to enable you to take a hot shower after a relaxing swim or to do some wash-up.

Just like in our homes, boat owners also feel the need to have hot water on their boats.

Hence will need to install a boat hot water heater unit to facilitate this.



Last update on 2023-12-15 / Affiliate links / Images from Amazon Product Advertising API

10 Best Boat Hot Water Heaters Reviewed

There are many water heaters in the market today, some of which have a modern touch while others are still in the bulky traditional designs.

In the boating industry, the water heaters used are usually either propane powered, use electricity, or make use of the waste from the engine to generate heat.

They are made from very high-quality corrosion-resistant material like aluminum steel or stainless steel, their unique design is to make them durable in any water conditions.

1. Whale Water Heater - Premium

Whale F1100 Water Heater, 11-Gallon Capacity, 120V, Front Heat Exchanger, 16 Inches W x 22 Inches D...

The Whale Water Heater 120V is the ideal boat hot water heater.

It efficiently maintains an ample supply of hot water of up to 11 gallons.

With its double-walled heat exchanger system, the whale water heater utilizes the closed cooling system to heat water as the boat is running.

Also, while not in motion, the heater can be run electrically using a heating element that can be connected to the boat power supply or a generator.

To ensure its durability, the heater is made of sturdy materials that are resistant to corrosion.

You can choose a casing material of your choice for this heater, which can either be galvanized steel.

This is more substantial than most but has a longer lifespan; aluminum steel that is epoxy coated and blends well with the features of a boat or stainless steel, which gives it a modern look.

An additional feature to ensure durability is the anode that comes with the heater.

The whale water heater is especially useful for boats that sail in hard waters with high dissolved salt concentration or high currents.

The anodes help to elongate the life span of water tanks by corroding themselves instead of the containers.

They, therefore, need to be replaced as need be.

The heater is ‘ignition protected’.

This is a measure put in place to ensure safety when the heater is being used in the engine room.

It has a pressure relief valve and a drain valve that allow you to drain out water during the cleaning process.

Pros & Benefits:

  • It is easy to install and quicker to heat water
  • It can run off electric or heat power
  • The heater comes with a two-year warranty
  • It helps to prolong the lifespan of the water tanks by preventing corrosion

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2. American Standard Electric Water Heater

American Standard CE-12-AS 12 gallon Point of Use Electric Water Heater

Second, on the list is the American Standard, a well-renowned water heater brand.

This brand seems to be a favorite among many boat owners.

This is a high-quality brand of water heater that is made to last long.

The heater can operate on gas or electricity.

The American Standard brand offers a wide range of models, each with different capacities to suit different needs.

The interior of the tanks on this heater is made from durable steel—couples with a fiberglass filler, and anodes that protect the tank from corrosion.

The anodes, however, have to be replaced as seen fit since they corrode with time.

Maintenance of the American Standard heater tank is easy since it has a hand hole allowance that allows for cleanup inside the container to remove the residues that build up with time.

The American Standard Water Heater is ideal for boat owners looking to heat a large volume of water on demand.

It has a large storage water capacity of up to 119 gallons of water with a heating element of up to 54Kw.

When it comes to warranty, the American Standard Water Heater is unbeatable.

The heater comes with a warranty of six years, while models with tanks lined with glass have a guarantee of twelve years, the same as the estimated lifespan of the heater.

Pros & Benefits:

  • It helps to reduce the cost of energy by its ability to retain heat for longer periods
  • Has an adjustable thermostat that enables you to regulate the temperature of the water as you feel fit
  • The American Standard Water Heater comes with a preset temperature and pressure relief valve
  • It is an easy to install point-of-use electric water heater: no long waits for the water to heat up
  • The American Standard Water Heater has a superior thermal efficiency

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3. Kuuma Water Heater

Kuuma 11841 Kuuma Water Heater with 120V Front Heat Exchange and Back Mount - 11 Gallons, Silver

Kuuma Water Heaters have an excellent reputation among popular boat manufacturers in the industry.

This is a dual powered water heater meaning it can be powered either by electricity or by using engine power.

Therefore, the water heater can be used whether the boat is on the sea or at the docks.

The heater’s casing is made from high-quality aluminum that makes it resistant to corrosion.

Also, the casing makes it excellent at retaining heat.

The Kuuma Water Heater has 11 gallons, which makes it the best for boats that have high hot water requirements.

However, it also has models that have a small hot water capacity of 5 or 6 gallons or a large capacity of 20-26 gallons.

To ensure safety when in use, the heater comes with an ‘ignition protect’.

This is to prevent any hazardous occurrences when in use in the engine compartment.

Pros & Benefits:

  • Kuuma Water Heaters are easy to install and maintain
  • The heater comes with a two-year warranty on the heater
  • It is highly effective when using either electricity or engine power
  • The heater comes with hose barbs and pipes for domestic water

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4. Bosch Tronic 3000 Water Heater

Bosch Electric Mini-Tank Water Heater Tronic 3000 T 2.5-Gallon (ES2.5) - Eliminate Time for Hot...

The Bosch Tronic 3000 is an electric mini-tank that is portable hence making it an excellent option for the outdoors as in a boat.

With its compact design and small size, the heater becomes easy to install by directly mounting it on a wall, under a sink or in a cabinet.

Bosch Tronicmodels come in different water capacities.

It is a cost-effective alternative since it operates without a tank.

The water capacity of these heaters could range anywhere from 2.5 to 7 gallons.

However, since the heater is small, you can only get enough hot water for one chore at a time.

The Bosch Tronic 3000 has a recovery rate of 6.8 GPH at about 90 F.

This rate varies depending on how cold the incoming water is.

The water pressure range is about 150 psi.

Although the heater is small, it has been equipped with features superior to other big models.

The Bosch Tronic 3000 is lined with glass that prevents it from corrosion over a long period of use.

The best feature of this model is that it is capable of supplying water to multiple sources simultaneously.

It’s also a good option if you are looking to conserve energy since it comes with a CFC- free form insolation.

It also comes with temperature control to enable you to adjust the water temperature to your liking.

The only downside of this heater is that it needs to be installed close to the hot water outlet.

Pros & Benefits:

  • The heater comes with a two-year warranty on its parts and a six-year warranty on the tank
  • Long lifespan: the tank is lined with glass making it corrosion resistant
  • It has a fast recovery rate; hence no long waits between drawing water
  • It is a point of use water heater which is fast and reliable: you get hot water as soon as you open the tap
  • With this heater, warm water delays or cut out is at minimal

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5. Atwood 94023 Water Heater

ATWOOD 94023 - Atwood/Water Heatrs & In Tanks (gch10a-4e) Atwood Rv Water Heater 10 Gallon LP Gas &...

Atwood water heaters are electric heating units that are highly reliable.

It’s lightweight, therefore makes it easy to install and to service.

This heater is made for an aluminum alloy that makes the storage tank resistant to corrosion hence elongates its life span.

It’s a great feature, especially for boats that sail in harsh weather conditions.

For the Atwood 94023, the hot water capacity is at 10 gallons with a heating element of 1400Kw and operating on 120V.

To ensure that the freshwater is not contaminated, this heater is made using the double tube technique.

To heat the water, the heater uses a hot water coolant.

This is not a point-of-use heater; therefore, you will need to give the heater time to heat the water.

It is, therefore, essential to ensure that the connection between the engine and the water heater is made correctly to prevent damage to the engine.

Pros & Benefits:

  • Due to its small size, this heater is ideal where there is minimal floor space
  • It comes equipped with a factory set thermostat and with a temperature and pressure valve
  • Keeps the water warm for a more extended period
  • Atwood heaters are effective and resourceful
  • The heater is compatible with most motors hence little to no adjustments are needed
  • Atwood heaters have multiple safety protections such as temperature-pressure relief valve, thermostats, and a limit switch

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6. Stiebel Eltron Tempra 24 Plus

Stiebel Eltron Tankless Water Heater – Tempra 24 Trend – Electric, On Demand Hot Water, Eco,...

This is yet another small electric heater that has no tank and is great for the outdoors.

This heater can be plugged in on a wall outlet, making it quite flexible and portable.

Its sleek design ensures that the heater can fit in places with minimal available space.

This heater has a flow rate of up to 4.68 gallons per minute, making it a higher performer than some gas heaters.

Since it doesn’t come with a tank, this water heater is considered the best in saving energy.

This is because water is only heated as required.

The Tempra 24 plus comes with a temperature control allowing you to adjust the water temperature to your liking.

A significant advantage of this heater is that two fixtures can use it at the same time.

One of its useful features is a thermostat that allows you to regulate water temperature as you use it.

Likewise, this heater comes with a high-tech flow control system.

This allows the regulation of water to be able to keep up with the demand.

When installed with a qualified technician, the product comes with a seven-year warranty.

Pros & Benefits:

  • No venting is required
  • The heater is small hence making it easy to install and maintain
  • Temperature changes are easy to adjust
  • Big on energy saving since it uses minimal energy
  • Ensures an unlimited supply of hot water
  • Since it has no tank, this water heater helps to save on space

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7. Water Heater Propane, Camplux Outdoor Portable Camping Gas Tankless Hot Water Heaters, 2.11 GPM,...

Water Heater Propane, Camplux Outdoor Portable Camping Gas Tankless Hot Water Heaters, 2.11 GPM,...

This is the perfect water heater for the outdoors with a 10-liter capacity and a 2.64 gallons per minute model.

It comes packaged with a showerhead, a gas regulator, and the required adapters.

Camplux Heater is small, compact, and lightweight making it easy to be positioned anywhere.

The heater is hooked to a propane cylinder powered by D-cell batteries making it the best choice for off-grid locations.

Despite its small size, the heater’s maximum power output is about 68,000 BTUs.

It also has a stainless steel burner and a copper heat exchanger that generates thermal energy efficiently.

Camplux has an energy control point that allows you to save energy when the weather is reasonably warm.

It also has an automatic shut-off switch that automatically switches the heater off when the temperature exceeds the safe levels.

On the contrary, its anti-freezing technology helps to drain out residue water through the drain plug during cold days.

Pros & Benefits:

  • Its thermal efficiency is very top-notch
  • Can work effectively without mains electricity
  • Comes with a showerhead and adapters on purchase
  • Has a 20-minute automatic safety device

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8. Isotemp Water Heaters

Osculati Isotemp Boiler Spa25

On this list, this is probably the most expensive choice, but it is worth it.

The Isotemp Water Heaters are more traditional, a bit heavier, and bulkier than the modern heaters.

It is the best choice if dealing with harsh water conditions.

These heaters are lined with a eutectic solution that enables water to remain warm for a more extended period.

Isotemp water heater is known to heat water to a temperature of up to 145F in an hour.

The unit can either be mounted horizontally or vertically and banded by two steadies, one on each side to help support.

This makes it robust when installed.

Additionally, the heater is made from stainless steel, which protects it from corrosion through hard water or harsh weather conditions.

The stainless steel casing is used for both the tubes and tanks, as well as any other part that might come into contact with water.

The Isotemp water heaters come in different sizes with a water storage capacity ranging from 4 to 6 gallons.

It has an immersion heating element of about 750W to 1000W and uses heat from the engine’s coolant to heat the water.

Pros & Benefits:

  • All models come with a five-year warranty
  • The polyurethane insulation helps preserves water temperature for long (up to 24 hours) hence the best when you want to use water without having to reheat
  • Comes with a safety relief valve
  • The water inlets and outlets in this product are carefully designed to minimize the mixture of hot and cold water

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The Raritan Water Heaters another famous brand in the boat water heater manufacturing industry.

These heaters are specifically designed for water machines.

At the price it comes in, this product works reasonably well.

Unlike the older model, the new and improved model of the tank is glass-lined with steel.

It, however, needs the support of anodes to prevent corrosion to the tank.

Raritan Water Heater fittings are galvanized while its tank is lined with a black foam sheet on the outside.

It comes with an adjustable thermostat that enables you to regulate the water temperature as you feel fit.

The heater has ignition and thermal overload protection to prevent any hazardous occurrences from happening.

It has a heating element of 120V with a water storage capacity of 20 gallons.

Pros & Benefits:

  • The heater is quick at heating water
  • The heater comes with a five-year warranty
  • Raritan Water Heaters are environmental-friendly; they have a CFC-free foam insulation
  • All models come with a five-year warranty on the tank and a two-year warranty on the heater
  • It is simple to install and has a design that makes it compatible with many pressure systems

10. Whale Seaward Water Heater

Whale Seaward 6 Gallon Hot Water Heater W/Rear Heat Exchanger Stainless Steel Exterior Marine ,...

The seaward heaters are made with stainless steel in several parts that are carefully joined together.

The plumbing pipes are galvanized while the tank is insulated with fiberglass, which protects it from corrosion.

This heater has a switch used to switch off the heater once the water temperature gets high.

It operates on a 12OV heat exchanger.

The Whale Seaward Water Heater uses a combination of both electric and heat exchangers to heat the water.

The seaward water heater has a water storage capacity of up to 11 gallons.

For safety, the heater has an ‘ignition protection’ to prevent any hazardous occurrences from happening when the engine is running.

Pros & Benefits:

  • This water heater has a large drain valve to drain residue during cold days
  • It has brackets welded on the tank to make it sturdy when mounted
  • This water heater comes with a temperature relief valve

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What To Consider When Choosing a Water Heater

Shopping for a water heater can be quite confusing and overwhelming.

There are many different types of brands and models available in the market, each with different specifications, build, capacity, and power.

A water heater can either make or break your boat ride experience.

A few things to keep in mind when planning to install or upgrade your water heater include:


With all the above considerations.

Choose a heater that fits your needs and is within your budget.

Although, it is best to note that with water heaters, the lowest cost is rarely the best value.


This is important as it helps to ensure the product works as intended.

The higher the warranty duration, the better.


How much available space you have on your boat to install the heater.

If working with little space, you might want to purchase a heater with no tank.

Energy Use

Heaters that use less energy are better since the energy supply on a boat is usually limited.


Water heaters can be quite hazardous if not correctly installed, especially when the engine is running.

It could result in a fire.

If not sure, ask a professional to install the heater for you.


Depending on the number of people, you anticipate being having on board regularly.

Choose a heater that can hold as much water as required.


Some heaters are best suited for commercial use, while others are made for small scale use.

Whether the boat is used for commercial use or personal use will determine the type of heater to purchase.


As much as most are highly durable.

You might choose to buy one made from stainless steel rather than one made from aluminum.

This is dependent on several factors, such as the type of water you sail on.

The prevalent weather condition in your region.

Final Thoughts

Nobody likes taking a cold shower.

Especially not on a cold day when you are out in the waters.

Therefore, having a boat hot water heater provides you with a different onboard experience, especially during the cold season.

Whether you are doing the installation by yourself or having a professional fix it for you, the process is quite easy.

A hot water heater installation ensures the storage and redistribution of freshwater within the system of the vessels.

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