Elecro Nano Cygnet 4KW

Elecro Nano Cygnet 4KW

Electric in-line pond heating for controlled koi and pond temperature support

Elecro Nano Cygnet 4KW is an Elecro electric in-line pond heater designed to provide direct water heating on suitable pond, koi pond, quarantine and holding systems. It is a useful option where controlled temperature support is needed and where the pond owner wants a simple in-line heating unit rather than an air source heat pump.

Electric in-line heaters are often chosen for smaller ponds, temporary holding systems, quarantine tanks, covered koi ponds and systems where accurate temperature control is more important than maximum energy efficiency. They convert electrical power directly into heat, so they are straightforward to understand, but correct sizing and sensible use are still very important.

This model sits in the Nano Cygnet range and has a rating of 4kW. The right size depends on water volume, heat loss, insulation, cover use, weather exposure and the temperature difference you are trying to maintain. A pond cover or insulation can greatly reduce running time because most heat loss comes from the water surface and exposed pipework.

When an electric pond heater is the right choice

An electric in-line heater can be very effective when you want dependable controlled heat on a modest water volume or a specialist system. For large open ponds, especially through winter, an air source heat pump or improved insulation may be more efficient, but an in-line heater remains a practical choice for quarantine, recovery, spawning, holding and koi temperature management.

Key benefits

• Direct electric heating for ponds, koi systems, quarantine tanks and holding systems.
• Thermostatic control for controlled temperature management.
• Useful for stable water temperatures when correctly sized and installed.
• In-line installation keeps the heater outside the pond and within the pipework run.
• Works best with a cover or insulation to reduce heat loss and running cost.

Technical information

• Type: Elecro Nano Cygnet titanium in-line aquatic heater
• Heating output: 4kW
• Electrical input: 4kW direct electric load
• Power requirement: 220–240V single phase, 18A load
• Control: Analogue thermostat, 0 to 45°C with 1.2°C differential
• Minimum flow: 1m³/h / 1,000 litres per hour
• Maximum flow: 17m³/h / 17,000 litres per hour
• Heating element: Grade 1 titanium
• Flow tube: Grade 1 titanium
• Thermal cut-out: 60°C manual reset
• Flow switch: Rhodium-tipped reed switch with titanium fulcrum pin
• Dimensions: 296mm x 176mm x 142mm
• Installation: Floor or vertical wall mounting; 4kW must be hardwired by a qualified electrician

Sizing and use advice

Always size a pond heater around actual water volume and heat loss, not just the headline litre capacity of the pond. A small insulated quarantine system is much easier to heat than a large uncovered pond exposed to wind and frost. For koi ponds, temperature changes should be gradual and fish behaviour should be monitored carefully.

The heater should be installed so that it has reliable flow whenever it is operating. Do not run an in-line heater dry, do not restrict the pipework more than necessary, and make sure all electrical work is suitable for outdoor pond equipment. Where a thermostat is fitted, set realistic temperatures and avoid sudden changes.

Helpful heating links

• Browse all pond heating
• Browse pond in-line heaters
• Compare pond air source heat pumps
• Water testing products

Helpful pond heating guide

For more help choosing pond heating equipment and understanding running considerations, see our related guide:

• pond heating guide