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Learn more - Silence








... silence sounds like this.


Why silence is important?

  • Ask your wife or girlfriend.
  • Sleep tight without noise.
  • Those in the neighboring boat appreciate you letting them sleep as well.

You should feel the heat not hear it!

  •  All Wallas heaters and cookers have been made for Marine use from the day one, which was 41 years ago! Laminar burning technology has been the enabler for silence.
  • Most of the other "boat heaters" are adaptations of  car heaters where the silence is, unfortunately, not golden. They use turbulent combustion, which is the opposite of laminar combustion.

Two outlets, less noise

  • Heat distributed  from a heater to the cabin can be calculated by using two factors:
    • Air velocity x cross-sectional area = Capacity
    • Air temperature
  • Air flow creates noise: the higher the velocity, the more annoying the sound. Thus, we have reduced the air velocity by half by doubleing the cross-sectional area of the outlets. This means that the heating effect has remained the same while the air flow has become quieter.
  • With two outlets, you can ensure, more efficiently, that one warm-air duct conducts a high enough air flow into the front cabin, while the other outlet distributes heat into the rest of the boat. Check out the figure.

Brushless blower motors

We know you appreciate a quiet environment, particularly at night. All of our diesel heaters are designed for very quiet operation. We tested our Dt heaters for sound output, using the following models: Each heater was fitted with two outlet ducts of 2 meters length, ending with 3411 outlets full open.The testing apparatus was placed one meter from the outlets.

Test 1: heater running at minimum power setting:

  • 22 Dt 44 dB
  • 30 Dt 45 dB

Sound levels between 40 and 45dB(A) are often characterized as equivalent to "a whispering in a library".

Test 2: heater running at maximum power setting:

  • 22 Dt 52 dB
  • 30 Dt 56 dB

Sound levels at 55dB(A) are often characterized as equivalent to "a peaceful conversation".


Integrated fuel dosing pump

  • Thanks to its small physical size, our fuel pump can be housed inside the heater housing.
  • We know that the sound level is not the whole truth. The tone of the noise also matters. Many boat heaters have a separate fuel pump which creates a loud clicking noise while a Wallas pump ticks like a watch.

Silent, powerful air motion with a silencer

  • Bigger boats need high air-volume heating. When air flows fast it can create noise. This is why we have available silencers for the air ducts. Please counsult with your Wallas supplier about whether a silencer is approriare for your application.
  • Even though our heater´s burners are silent, we recommend the use of silencers because they reduce the sound level by 50-75%. This is the case especially if you have less than 2 m duct intake or outtake running from the heater into your cabin where you sleep.




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