Rex Nordic



Heating system for whirlpools, swimming pools and hot tubs!

Quick heating – hot tub in 2 hours

Heats with the touch of a button

A timer for improved energy efficiency

Year-round use

No visible smoke – can be used in residential areas

Low consumption. Economical.

Works with biodiesel


  • Hot tub water volume: 1,500 L
  • Heating time from +7 °C to +38 °C approx. 2 h, including 1 hour water filling
  • Consumption = about 4 l biodiesel or diesel


Heating system for hot tubs, swimming pools and whirlpools

Rexener Bio Water Heater can be installed on a new or existing Spa, pool or hot tub water heating system. Rexener Bio Water Heater can replace your high consumption electric heater or a traditional wood-heated hot tub heater. Water heating can begin before the pool is full of water. This makes the heating faster.

The installation / replacement is easy and you can choose the installation package of your needs.

You can use Rexener Bio Water Heater with biodiesel, diesel or “red diesel”. You can also use the Rexener Bio Water Heater in a suburban area, as the heater will not cause visible smoke or smell that could disturb your neighbours. The high efficiency of Rexener Bio Water Heater heater also means that the use of the heater does not cause much harmful exhaust emissions. In practice, the exhaust only emits carbon dioxide. The heater only needs about 80W of electrical power.

With Rexener Bio Water Heater, you can keep the same water in your hot tub week after week by connecting a sand filter to the heater and using the appropriate pool chemicals. When the hot tub or pool is more convenient to use, the usage is more frequent. You can even get Rexener Bio Water Heater from us with an installation service.

Rexener Bio Water Heater also has the power to heat up a really large 50,000 liter swimming pool – all year round – even in Nordic countries! Rexener Bio Water Heater is truly reliable and we give it a 3 year warranty.


I would definitely recommend Rexener Bioheaters to others. It is a top product. I am also very happy with the service I have received in connection with questions about the product. Rexener Bioheater will extend our bathing season, so we will use the bath throughout the year.

Reliable and easy to use

Rexener Bioheater is heating up our swimming pool, whose volume is almost 50 m3. Rexener Bioheater has been easy to use and has significantly increased the use of the swimming pool.

Pool season is all year round

The customer lets the hot tub cool down during the week and he increase the temperature for the weekend when the hot tub is used. This makes its use really cost-effective. The heater quickly heats up the water to the desired temperature, and there is no need to worry about getting firewood.

Hot tub on an island

Bio Water Heater product packages

- based on your needs.


Bio Heater Basic

For you who already have a circulation water pump and installation supplies

1 890 £
  • Basic package

  • Installation kit

  • Circulation pump

  • Energy Saving Kit

  • Mass filter

  • Heater unit


Bio Heater Bronze

For you who already have a circulation water pump. Great for swimming pools!

1.990 £
  • Basic package

  • Installation kit

  • Circulation pump

  • Energy Saving Kit

  • Mass filter

  • Heater unit


Bio Heater Gold

The perfect kit for replacing the wood stove with the filter package

2.290 £
  • Basic package

  • Installation kit

  • Circulation pump

  • Energy Saving Kit

  • Mass filter

  • Heater unit

Gold Plus

Bio Heater Gold Plus

Preinstalled in the larger wooden protective case

3.090 £
  • Basic package

  • Installation kit

  • Circulation pump

  • Energy Saving Kit

  • Mass filter

  • Heater unit



  • Extra savings; by running the heater every 6 hours, you save up to 2/3rd of the heating costs compared to continuous heating.
  • Let the water temperature get lower when you don't use your Spa/Pool/Hot Tub
  • Fast heating up to bathing temperatures again
  • Available as a spare part


Weight43 kg
Dimensions38 × 58 × 86 cm
Consumption2,0 L/h (Note: thanks to the thermostat, actual consumption is much lower)
Power18,5 kW / h
FuelBiodiesel, diesel or fuel oil
Thermostat 0-40ºC
Power consumption80W (230V, 50Hz)
Noise Level48 dB
ControlDigital touch panel
Tank30 L External tank
Water connection38 – 75 mm (38 mm Inner diameter)
Pipe dimensions100 cm without pipehat and 110 cm with pipehat.

Rexener articles

FAQ Page - Bio Water Heater

Get answers to common questions.