Wood vs. Gas Hot Tub Heating – Which System to Choose?

AquaRelax hot tubs can be equipped with either wood-fired or gas heating systems.
In this article, you’ll find out which solution best suits your needs: a hot tub with a wood-burning stove or a gas heater.

You’ll also learn how long it takes to heat the water and which option is better suited for your main home or holiday residence

  • Wood-Fired Heater

    Fast water heating (on average in 2–2.5 hours)
    No need for gas or electricity connection
    Suitable for any property, including off-grid homes
    Creates a special ambiance: scent of wood, crackling fire
    Find out the price
  • Gas Outdoor Heater

    Fast water heating up to 24 kW without wood or constant monitoring
    Runs on propane gas cylinder with automatic shut-off in case of overheating or water flow stop
    Efficient consumption — up to 4 kg of gas for 1200 L
    Find out the price

GAS WATER HEATER 20–24 kW
High-performance gas water heater designed, for example, for hot tubs and spas.
The heater has high power output for fast and safe water heating. Flow rate — 10 L/min, the temperature difference between the inlet and outlet is 25 °C. This means a temperature increase of approximately 15 °C per hour for 1000 liters of water.
Nominal power: 20 kW (30 mbar, 1.5 kg/h)
With a 30 mbar regulator and 2 kg/h consumption, the power output is 24 kW.
Gas consumption: 1.5 – 1.6 kg/h
Heating time for a 1200-liter tub (from 6 to 37 °C): 2.5 hours
Gas usage: 4 kg
Fuel: Liquefied propane gas (LPG), operating pressure 30 mbar.
Suitable for heating water in hot tubs, spas, showers, dishwashing, etc.
Heater dimensions:
Height: 740 mm
Width: 345 mm
Depth: 160 mm
The heater has automatic ignition, activated by a minimum water flow of 7 L/min. The HGUNION19 pump included is specifically designed for this purpose.
If the water flow stops, the gas is automatically shut off. The same happens if the outlet water temperature exceeds 75 °C or the flame goes out.
The heater features a digital temperature display for inlet water.
An optional protective box is available to shield the heater from wind and rain. The front panel of the box can be removed during use. The case is made of heat-resistant material on the back and sides, with a slanted thermal shield on top to direct the heat outward.
In the photo — the AquaRelax wood-fired heater for a hot tub, installed in the technical compartment.
AquaRelax Heating Systems — The Heart of Every Hot Tub
We use high-performance heaters, specifically engineered to deliver fast and even heat distribution. Depending on your space and preferences, you can choose:
  • Wood-burning heater — completely off-grid and atmospheric, perfect for remote properties or nature-focused settings.
  • Gas heater — compact, automated, and convenient; ensures fast heating with zero effort.
Each unit is built with heat-resistant stainless steel and designed for safe operation, efficient heat transfer, and easy maintenance.
Our heaters can be installed outside or integrated into a dedicated technical compartment.
Since we manufacture them in-house, we guarantee the highest quality in every detail.
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