The question isn't always whether you need hot water on the go. Sometimes it can be about how quickly you want it, and that's where the Aqueous 6L 240V Water Heater truly shines.
As its name suggests, this hot water system uses 240V AC power to heat water rapidly. It reaches the maximum temperature (75°C) — ideal for most users, as it provides a larger volume of warm water for showering, dishwashing, cooking, or even laundry — in just minutes.
This caravan hot water heater also features a premium nickel-based Incoloy heating element, a well-constructed storage tank, excellent thermal insulation, comprehensive safety features, and several other impressive qualities we'll cover in this review. Thus, it's an outstanding addition to any caravan, campervan, RV, or boat.
What Is the Aqueous 6L 240V Water Heater?
The Aqueous (6L 240V) Water Heater is one of the top storage water heaters available for caravans, campervans, RVs, and boats. As a point-of-use (POU) unit, it heats water only when needed and delivers it directly to your sink or shower.
The unit has a compact design with a 6-litre capacity, which is pretty sufficient for off-grid applications. At the core, it includes a high-performance nickel-based Incoloy heating element that ensures rapid heating of your water.
The heating element works hand in hand with a high-precision thermostat to deliver your desired hot water temperature. You can easily adjust the thermostat temperature setting via a rotary dial on the control panel.
As a 240V AC accessory, this electric hot water system comes with an integrated plug for a standard AC outlet, so you'll just need to plug it into the inverter. And thanks to its 1kW heating element, it can heat the tank's 6 litres in 8–30 minutes, depending on your desired hot temperature.
What's in the Box?
When you receive your order, the heater arrives as a reasonably bulky package containing all the essential components. Upon unboxing, you'll find:
- The water heater: The main storage unit that heats your water for showering, dishwashing, or cooking on the go.
- Pressure safety valve: A fitting that screws onto the heater to release excess internal pressure.
- Printed user guide: A pamphlet with detailed instructions for installation, operation, and maintenance.
- Installation components: The mounting bracket, bolts, and screws required to secure the heater in your caravan, campervan, RV, or boat.
How Big Is This 240V Water Heater?
Although we've said the unit is bulky, it is far more compact than traditional household water boilers. It measures approximately 30.5 × 30.5 × 30.4 cm — roughly the footprint of a standard picture frame. This makes it easy to fit into tight spaces without sacrificing valuable room, such as under a sink, in a cabinet, beneath a fixed bench, or under a bed.
The unit weighs about 6.1 kg when empty — a manageable weight for most people to carry. When full of water, however, it reaches 12.1 kg. Thus, you should mount it in a location capable of supporting at least 25 kg for safety and stability, following the common "double weight" rule used for items like TVs.
How Durable Is the Build Quality?
This storage water heater is proudly designed and developed in Australia, where it has been rigorously tested under extreme local conditions to ensure reliable long-term performance on rough terrain.
This durability has been achieved through several key features:
- The outer housing is made from high-impact ABS plastic, which resists breaking, shattering, or cracking even under constant vibration.
- The inner water storage tank uses a single vertical seam weld, minimising potential leak points and improving overall structural integrity for a longer lifespan.
- The water tank includes a patented Blue Diamond enamel coating (a glass-like lining) and a magnesium anode rod, both of which guard against rust and corrosion.
- The heating element is constructed from a premium nickel-based superalloy (Incoloy), offering superior thermal conductivity, corrosion resistance, and longevity compared to traditional copper elements.
What Inverter Do You Need to Run It?
The heater operates on a 240V @ 50Hz AC power supply. To use it in your adventure vehicle or boat, you'll need a suitable 240V/50Hz inverter. The unit comes with an integrated power plug, so you just need to plug it into the inverter's AC outlet.
The heating element draws a maximum of 1 kW (1000 watts). At 240V, this equates to approximately 4.17 amps (1000 watts ÷ 240V). It is therefore compatible with mid-to-high-power inverters, such as the Victron 12/1600 Phoenix or Enerdrive 2000W/12V ePower.
How Hard Is It to Install?
Installing this hot water system is moderately challenging. The process involves securing the unit in place, connecting the water plumbing, and ensuring the power supply (inverter) is correctly configured.
The plumbing stage is typically the most time-consuming, as you need to plan the routing from your fresh-water tank and select the optimal pipe paths. You will also require suitable water piping, tube adapters for connections, and a thermostatic mixing valve to regulate water temperature at the shower or kitchen sink.
Fortunately, a one-way pressure relief safety valve is included in the kit, so no separate purchase is necessary.
How Easy Is It to Operate?
This storage water heater has been designed with caravanners, RVers, and boat cruisers in mind. It is extremely simple to use, even for novices. You simply fill the storage tank with water, plug the power cord into the inverter's socket, and switch it on.
Once power is supplied, the red and green indicator lights will illuminate to show that the water is heating. You can then use the thermostat control knob on the face of the heater to select your desired water temperature.
How Fast Does It Heat Water?
The Aqueous 6L 240V Water Heater features a premium 1 kW Incoloy heating element chosen specifically for rapid heating. It also includes a precise variable thermostat that allows you to set the water temperature anywhere between 30°C and 75°C.
To adjust the thermostat, turn the control knob on the front of the unit clockwise for a higher temperature or anticlockwise for a lower one.
At full power, the heater utilises the entire 1 kW (1000 W) capacity of its heating element. Using these specifications, we can estimate the energy required and the time needed to heat the water from 20°C to 75°C.
Part 1: Energy Required
Energy required (Q) = mass (m) × specific heat capacity of water (c) × temperature rise (ΔT).
For 6 kg of water (6 litres ≈ 6 kg), a 55°C temperature rise, and water's specific heat capacity of 4184 J/kg°C:
Q = 6 kg × 4184 J/kg°C × 55°C = 1,380,720 joules. 1,380,720 joules ≈ 383.53 watt-hours (Wh).
Part 2: Time Required
Time (t) = energy required (Q) ÷ heating element power
t = 383.53 Wh ÷ 1000 W = 0.38353 hours ≈ 23 minutes
Using the same conditions:
- Heating 6 kg of water from 10°C to 75°C takes about 28 minutes.
- Heating from 20°C to 40°C takes approximately 8 minutes.
How Much Warm Water Can a 6-Litre Tank Deliver?
The heater has a 6-litre storage tank, which is ample for most off-grid applications. When heated to the maximum 75°C, the 6 litres of hot water can be mixed with cold water to deliver up to 13 litres (or more) of comfortably warm water — enough for a full shower or two, depending on the desired temperature and incoming cold water temperature.
To estimate the total mixed water volume (Tmv), we can use the formula:
Tmv = Vh + Vc, where:
- Vh = volume of hot water from the tank (6 litres)
- Vc = volume of cold water added
Vc can be calculated as: Vc = Vh × (Th – Tt) ÷ (Tt – Tc), where:
- Th = hot water temperature (e.g., 75°C)
- Tt = target mixed water temperature
- Tc = cold water temperature
Examples at Maximum Thermostat Setting (75°C)
Solution 1: Target 40°C, cold water 10°C. Tmv = 6 + [6 × (75 – 40) ÷ (40 – 10)] = 13 litres
Solution 2: Target 38°C, cold water 20°C. Tmv = 6 + [6 × (75 – 38) ÷ (38 – 20)] ≈ 18 litres
What Safety Features Are Built In?
This unit is built to last and comes with a 12-month warranty that reflects confidence in its build quality and reliability. It also has several safeguards to ensure long-term optimal performance:
- An IPX4 waterproof rating that protects internal components from splashing water — say, when mounted under a sink or closer to the shower.
- Over-pressure protection — the safety valve that you screw on the tank to automatically release pressure if it exceeds 0.85 MPa.
- Over-temperature protection — a safety feature that automatically disconnects the heating element if the temperature exceeds 93°C.
It's worth noting that the over-temperature safety feature does not reset automatically. After it trips, you must manually reset it by removing the control panel and pressing the reset button on top of the tank.
How Does It Compare with the 12V Model?
In a nutshell, these are the most critical features of this hot water system for anyone wanting warm or hot water on the go in a caravan, campervan, RV, or boat. It is a variant of the DC-powered Aqueous 6L 12V model, so the two share many similarities.
See the comparison below:
| Aqueous (6L 240V) Water Heater | Aqueous (6L 12V) Water Heater | |
| Type of water heater | Point of use | Point of use |
| Dimensions | 305 x 305 x 304 mm | 305 x 305 x 304 mm |
| Net weight (empty) | 6.1 kilos | 6.1 kilos |
| Power requirements | 240 Volts AC (4.2 amps) | 12 Volts DC (15 amps) |
| Power consumption | 1000 Watts (@ 50Hz) | 180 Watts |
| Water storage capacity | YES (6 litres) | YES (6 litres) |
| Water storage pressure | 0.85 MPa | 0.85 MPa |
| Water heating element | 1 kW | 1 kW |
| Water heating control | 30°C - 75°C | 30°C - 75°C |
| Waterproof protection | YES (IPX4) | YES (IPX4) |
| Protective safeguards | Protected against over-temperature, over-pressure, corrosion, and others | Protected against over-temperature, over-pressure, corrosion, and others |
| Warranty support | 12 months | 12 months |
Should You Get This 240V Caravan Hot Water Heater?
That depends on your priorities — particularly whether you want to heat water faster. The 1 kW heating element in the Aqueous 6L 240V model can operate at full capacity, allowing it to heat water up to six times faster than the 12V version, which is limited to 180 W.
Then again, the 240V model requires a reliable 50 Hz inverter (1500 W or higher) for consistent performance. Its higher power draw will also place greater strain on the battery bank connected to the inverter, unlike the 12V version, which is far gentler on batteries due to its low 180 W consumption.
Frequently Asked Questions
How long does the heater take to heat water?
It can heat the tank's 6 litres in 8–30 minutes, depending on your desired temperature. For example, heating from 20°C to 40°C takes approximately 8 minutes, from 20°C to 75°C about 23 minutes, and from 10°C to 75°C about 28 minutes.
Do you need an inverter to run a 240V water heater in a caravan?
Yes. The unit runs on a 240V @ 50Hz AC supply, so you'll need a suitable inverter — ideally rated 1500 W or higher for consistent performance. At full power it draws 1000 watts, or approximately 4.17 amps at 240V.
How much warm water does the 6-litre tank provide?
When heated to 75°C and blended with cold water, the 6-litre tank can deliver 13 litres of 40°C water (with 10°C cold water) or approximately 18 litres of 38°C water (with 20°C cold water).
What happens if the heater overheats?
Over-temperature protection automatically disconnects the heating element if the temperature exceeds 93°C. This safety feature does not reset automatically — you must remove the control panel and press the reset button on top of the tank.
Want fast hot water in your caravan, campervan, RV, or boat? Order the Aqueous 6L 240V Water Heater from Campervan Builders today.
