Poolex Nano Heat Pumps

Choosing a Poolex Nano FI heat pump

Nano FI 3 or Nano FI 5?

The two models have different performance figures and circulation requirements. The Nano FI 5 delivers 2.20–5.00kW at 26°C air and 26°C water, falling to 1.56–3.50kW at 15°C air and 26°C water. Its specified flow is 2.15m³/hour. Use the individual model specifications to compare both sizes under the same test conditions. A larger nominal rating is not a substitute for checking the available flow through a small pool filter pump.

Full inverter control in a compact unit

Inverter operation allows the compressor and fan to vary their output as demand changes. This differs from a fixed-speed heater that cycles at a single operating speed. Built-in 2.4GHz Wi-Fi supports remote control through the Poolex app. Check signal coverage at the installation position, and retain access to the local controls for operation and maintenance.

Can a Nano FI heat a koi pond?

The UK distributor’s Nano FI manual separates a 15–40°C heating-mode range from a 7–40°C automatic-mode range. Automatic mode can switch between heating and cooling; it is not the same as a heating-only thermostat. Before selecting a Nano for a low-temperature pond, confirm the supplied controller, intended mode and actual winter heating duty. A summer pool volume rating does not demonstrate that a pond can be held at 12°C in winter.

Planning an above-ground pool installation

Account for the pool’s exposed walls, surface area, cover and wind exposure. Check the actual circulation after the filter, hoses and fittings, not just the pump’s maximum advertised output. Match hose connections and any bypass to the supplied fittings and manual. The compact cabinet still needs clear outdoor airflow, a stable base and a route for condensate. If the system is put away for winter, drain it according to the instructions before frost can damage trapped water.

Compare the models in this range

Open an individual model for its full technical data, current price, installation guidance and delivery information. Electrical phase is shown separately so similarly named versions can be compared correctly.

Heating output is not electrical consumption

kW can describe either the heat delivered to the water or the electricity used, so check which figure is quoted. In performance tables, A refers to air temperature and W to water temperature, in degrees Celsius. COP compares delivered heat with electrical input at a stated test condition. Compare like-for-like figures rather than using the highest advertised efficiency to predict your annual bill.

Before you order

Measure the water volume and surface area, decide on your target temperature and heating season, and note the cover and insulation. Check the available electrical supply, delivered water flow and outdoor installation space. A suitable cover can reduce the heat that must be replaced. Tell us about exposed filters, pipework and wind so that these are included in the recommendation. During frost, follow the manual’s circulation and drain-down instructions; switching an idle heater off does not remove trapped water.

More help with your heating system

Our pond heating guide explains winter sizing, covers and system choices. Use the air source heat pump filters to compare electrical supply, output, control type and budget across ranges. For circulation equipment, explore our pond pumps and check the delivered flow through the complete circuit.

Other ranges to compare

• Poolex Silverline Top heat pumps
• Thermotec Nova heat pumps
• Thermotec Apex heat pumps
• Thermotec Edge heat pumps
• Thermotec Neo heat pumps

Different ranges suit different temperatures, seasons and installations. Compare the controller settings and cold-weather output as well as nominal kW before changing to an alternative.