How would you feel about enjoying a hot shower while on the road or camping off-grid? A reliable water heater is the most convenient solution for a comfortable, warm shower on the go, and one excellent option for your adventure van is the Aqueous (6L 12V) water heater.
As a point-of-use hot water system, this heater provides warm water exactly where you need it. It is equipped with a 1kW nickel-based superalloy heating element for rapid water heating, and its simple yet sophisticated interior design ensures optimal performance without discolouring the water or damaging the steel tank.
In this guide, we review this compact 12V water heater in detail, covering its design, construction, expected mixed water volume, and the other features you can expect after installing it in your caravan, campervan, RV, or motorhome.
What Is the Aqueous 6L 12V Water Heater?
The Aqueous (6L 12V) water heater is one of the most convenient options available for your campervan, caravan, RV, or motorhome. It is a "point-of-use" (POU) water heater, meaning the water is heated right next to where it will be used — typically close to kitchen or shower fixtures.
As its name indicates, the unit uses a 12V heating element, allowing you to connect it directly to your battery or solar system without needing an inverter. It has a compact 6-litre tank capacity, which helps maximise the limited space in your van, yet it can heat water up to 75°C, providing 12–14 litres of warm water for showering or washing dishes.
The premium heating element is complemented by a high-precision thermostat, adjustable between 30°C and 75°C. It also includes over-temperature protection, which automatically turns off the heating element if it becomes too hot.
The chart below highlights other features and specifications of this 12V hot water system:
| Aqueous (6L 12V) Water Heater | |
| Type of water heater | Point of use |
| Dimensions | 305 x 305 x 304 mm |
| Net weight (empty) | 6.1 kilos |
| Power requirements | 12 Volts DC (15 amps) |
| Power consumption | 180 Watts |
| Water storage capacity | YES (6 litres) |
| Water storage pressure | 0.85 MPa |
| Water heating element | 1 kW |
| Water heating control | 30°C - 75°C |
| Safety features | Against electrical fault, overheating, overpressure, and IPX4 waterproof |
| Warranty support | 12 months |
What's Included in the Box?
When you order this 12V water heater system, the package contains only the essential components. These include:
- The water heater unit: The core heater, which integrates a water storage tank, heating element, internal circuitry, terminal leads, control panel, and water inlet and outlet ports.
- Pressure safety valve: A component that screws onto the water heater to release excess internal pressure.
- Printed user guide: A pamphlet containing specifications and instructions for installation, operation, and maintenance.
- Installation components: The basic items needed to mount the water heater in your van, including a mounting bracket and bolts.
Will It Fit in a Caravan or Campervan Cabinet?
This unit is remarkably compact, measuring just 30.5 cm × 30.5 cm × 30.4 cm. This size allows it to fit comfortably in a standard kitchen cabinet found in caravans, campervans, and RVs.
The unit weighs only 6.1 kg when empty, but it becomes heavier once filled with water. For this reason, you should mount it in a location that can securely support the full weight, such as under the kitchen sink or inside a cabinet or utility cupboard.
Even though we recommend concealing it under the sink or in a cabinet, the heater boasts a sleek, modern design with smooth curves, a clean white finish, and subtle dark accents. This means you can mount it in plain view without it looking out of place.
How Durable Is the Construction?
We are proud to say this water heater is a product designed and refined in Australia to endure the country's demanding off-grid conditions.
The exterior housing is made from high-impact ABS plastic that resists cracking and shattering, even under intense vibration. The interior features a proprietary glass lining (Blue Diamond Enamel Coating) and a magnesium anode, both of which protect against rust and corrosion, significantly extending the system's lifespan.
Moreover, the unit includes a superior Incoloy heating element — a high-performance nickel-based superalloy designed to withstand high temperatures, corrosion, and pitting for a longer service life.
How Much Power Does a 12V Water Heater Use?
The heater operates on a 12V DC power supply. You can connect it directly to your vehicle's battery system — either via the battery bank busbar, by splicing into a nearby accessory, or through an Anderson plug.
The heater draws approximately 13.3 amps, which we can round off to about a 15-amp draw. This means it only uses 180 watts from your battery or solar system, making it highly energy-efficient.
Is It Easy to Install?
Like most caravan, campervan, and RV accessories, this hot water system can be installed as a DIY project. However, the process is moderately challenging due to the required plumbing connections and electrical wiring.
The kit already comes with a standard mounting bracket, bolts, and screws, along with a pressure relief safety valve. Hence, you will only need to gather the remaining plumbing components, such as tube adapters, water hoses, faucets, and a shower head.
Important Installation Notes
- We strongly recommend having a professional install the heater. Incorrect installation or the use of substandard components may damage the unit and void the warranty.
- Install the water heater as close as possible to the points of use (kitchen sink and shower) to minimise heat loss through long piping.
- Ensure the electrical wiring is properly earthed and fused to protect against overcurrent, overvoltage, and short circuits.
- To prevent unnecessary battery drain when the heater is not in use, install a switch on the power connection. If possible, choose a switch with timer functionality for added protection in case you forget to turn it off.
How Do You Use It?
Once installed, the system is simple to operate. You just need to fill the 6-litre reservoir with water, turn on the main power switch, and adjust the thermostat's rotary dial to your desired temperature. The red and green LED indicators on the control panel will light up, showing your water is heating.
Once the water is hot, you can enjoy a comfortable shower by adjusting the temperature at the mixer valve.
How Fast Does It Heat Water?
The water heater tank includes a 1-kilowatt (kW) heating element to ensure rapid heating of your water. However, the whole system is designed to draw up to 180 watts to moderate its current draw for the 12V DC system.
To ensure the heating element doesn't continue to run at its peak rating (1 kW), the unit includes built-in auto thermostatic cycling. This allows the heater to automatically cycle on and off — turning off when the water temperature reaches the set temperature, then turning back on when it drops below the setpoint.
The built-in thermostat can be adjusted from 30°C to 75°C, which you can easily control with the integrated rotary dial. You can then use the thermostatic mixing valve (or mixer taps) to control how hot you want the output water to be for your kitchen sink or shower.
How Much Hot Water Do You Get from a 6-Litre Tank?
The water storage tank of this heater isn't the largest, but it's sufficient for a warm shower on the go. While the tank offers only 6 litres of heated water, the total mixed volume (say, 75°C hot water + 10°C cold water) can be 13 litres of 40°C warm water.
To calculate the total mixed water volume of warm water, you simply combine the volume of cold water needed with that of the hot water storage. This can be estimated as follows:
Tmv = Vc + Vh, whereby Vc = Vh × (Th – Tt) ÷ (Tt – Tc), and...
- Vc is the volume of cold water needed
- Vh is the volume of hot water in the heater storage tank
- Th is the temperature of the hot water in the storage tank
- Tt is the target temperature of the total mixed water
- Tc is the temperature of the cold water connected to the thermostatic mixing valve (or mixer tap)
- Tmv is the total mixed volume of water after combining the cold and hot capacities
For instance, the Tmv for a temperature target of 40°C would be 13 litres when:
- Vh = 6 litres
- Th = 75°C
- Tt = 40°C
- Tc = 10°C
In this example, Vc would be 7 litres — 6 × (75 – 40) ÷ (40 – 10). Then, Tmv = 13 litres (6 + 7).
What Safety Features Does It Have?
This heater is designed not only to heat your water on the go today, but also to serve you for a long time. It includes a host of safety features to ensure optimal performance, enhanced durability, and extended lifespan. These features include:
- Auto thermostatic cycling: The first protective safeguard of this water heater. It automatically cycles on and off to prevent the 1 kW heating element from reaching its rated peak heating.
- Over-temperature protection: This feature prevents the electric water heater from overheating by disconnecting the element at the core circuitry. The safety mechanism automatically trips when the heating element exceeds 93°C.
- Over-pressure protection: The water heater storage tank is rated at 0.85 MPa (megapascal). If the internal pressure is higher than this rating, the safety valve will automatically release it.
- Magnesium anode: Inside the storage tank is a sacrificial magnesium anode rod that prevents rusting of the steel material. It achieves this by creating a galvanic cell (corroding first before the steel) and providing cathodic protection (releasing electrons that turn the steel tank into a cathode that can't rust).
- One-way pressure release safety valve: This electric hot water system comes with a pressure relief safety valve that you screw onto the cold water port. You use it for releasing internal pressure. The safety valve is also one-way only, preventing water from the storage tank from feeding back into your van's supply pipeline.
- Blue Diamond enamel coating: A patented glass-like lining that prevents the steel storage tank from coming into direct contact with water. This enhances the durability of the storage tank by preventing rusting, corrosion, and scale accumulation.
- IPX4 waterproof rating: The whole unit is well protected against splashing water from any direction. Hence, you can install it under the sink or even closer to the shower without worrying about water damage. However, the heater shouldn't be subjected to powerful water jets or full submersion in water.
Is the Aqueous 6L 12V Water Heater Worth It?
Yes, the Aqueous 6L 12V water heater is a worthwhile investment for your campervan, caravan, RV, or boat if you want to enjoy near-instant hot or warm water for dishwashing or showering on the go. It's compact to maximise your limited van space, and the amount of water heated is sufficient for most off-grid users.
The heater is also well made with high-quality materials and comprehensive protective safeguards to guarantee the best performance, enhanced durability, and extended lifespan — even under Australia's tough conditions. You even get 12 months of warranty, which covers replacement or repair at no extra cost.
Frequently Asked Questions
How much warm water does a 6-litre 12V water heater provide?
Although the tank holds 6 litres, heating the water to 75°C and blending it with cold water through a mixing valve delivers 12–14 litres of warm water. For example, 6 litres at 75°C mixed with 10°C cold water yields about 13 litres at 40°C.
How many amps does the heater draw from a 12V battery?
It draws approximately 13.3 amps (round it off to about a 15-amp draw), which equates to just 180 watts from your battery or solar system — no inverter is required.
What temperature range can you set on the thermostat?
The built-in high-precision thermostat is adjustable between 30°C and 75°C via the rotary dial, with over-temperature protection tripping if the element exceeds 93°C.
Can I install the heater myself?
It can be installed as a DIY project, but the plumbing and electrical work make it moderately challenging. We strongly recommend professional installation, as incorrect installation or substandard components may damage the unit and void the 12-month warranty.
Ready to add near-instant hot water to your van build? Shop the Aqueous 6L 12V water heater at Campervan Builders today.
