Electric pool heaters

To size the heater correctly, allow for between 1 kW and 1.5 kW per cubic meter of water if you want to raise the temperature quickly in residential pools or spas.

For volumes of up to 20 m³, compact options such as the Zodiac RE/LE 3 electric heater - Ref. W40LE03 provide 3 kW of power with a precise thermostat. If your pool is medium-sized or needs to offset heat loss in cold areas, the Zodiac Red Line 3 electric heater - Ref. W40DE3 provides consistent heating with corrosion-resistant materials.

Always consider your home's contracted amperage before choosing the final unit.

For that volume with a 230 V power supply, you need a high-power unit designed specifically for single-phase lines without causing voltage drops.

The model shown is the Zodiac RE/U 12 single-phase electric heater - Ref. W40TIT12M, which supplies 12 kW directly from your electrical panel's domestic power supply. This unit features a pure titanium heating element and a safety flow switch that stops heating if water flow stops.

Before completing the installation, check that your main breaker and panel cable gauge can handle the required continuous current.

Electric pool heaters require a dedicated line from the main electrical panel and a plumbing connection to the return circuit.

• Install after the sand filter and before any chemical dosing system or salt chlorinator.
• A bypass connection must be installed to adjust the flow rate and make maintenance easier.
• Dedicated 30 mA residual-current device and circuit breaker rated according to the heater's kW.
• Electrical interlock with the filtration pump to prevent the unit from heating when there is no water circulation.

Following this technical plan prevents thermal cutouts and ensures the manufacturer's warranty remains valid.

An electric heater is cost-effective for vacation homes or occasional use because it requires a significantly lower initial investment and reaches high temperatures within a few hours.

While a heat pump depends on the outdoor air temperature and needs mild days to operate efficiently, the heater delivers consistent, direct performance whether the ambient temperature is 5 °C or 15 °C. Although its instantaneous electricity consumption is higher, the total cost of ownership is more than offset if swimming is limited to weekends or holiday weekends during the season.

Compatibility with salt electrolysis depends exclusively on the materials used to make the heating chamber and the device’s internal heating element.

• Titanium heating elements: tolerate high salt concentrations without corrosion or chloride pitting.
• Stainless steel or Incoloy heating elements: degrade faster and oxidize severely if the water contains dissolved salt.
• Polyamide or Noryl casings: insulate electrical components from the corrosive effects of treated water.

Choosing only heaters equipped with titanium from the outset prevents water leaks and irreparable failures in your filtration system.

The essential first step is to cover the water with a floating thermal blanket as soon as swimming is over.

More than 70% of heat loss from an outdoor pool occurs through evaporation from the water’s open surface at night. By placing a thermal cover over the pool, the energy generated by the heater stays in the pool, reducing thermostat heating cycles by up to 50%. Additionally, insulating outdoor PVC pipe runs with cellular insulation prevents temperature drops along the supply line.

Automatic shutdown is almost always caused by internal safety devices being triggered due to insufficient flow or overheating.

If the pump pre-filter or sand filter accumulates too much dirt, the water flow rate drops below the flow switch’s minimum threshold. At that point, the sensor cuts the power to prevent the heating element from running dry and burning out. Once the filter has been cleaned and normal water circulation restored, the heater safely resumes its usual operating cycle.