How to reduce and insulate hot tub noise

How to soundproof and insulate hot tub noise
Hot tub, Jacuzzi and spas can be divided into two types: the ones that have a built-in pump, inside the housing of the bath, and the ones with an external pump. Almost all hot tubs have the same noise problem, impact noise and airborne noise caused by the pump. Another problem related to hot tubs is people talking, laughing, music and of course the sound of bubbling water. Let’s solve these problems!

Soundproof and insulate hot tube pump
The housing of a pump is usually made of a light material, such as plastic or plywood. The lack of mass (weight) of these materials, and thus the housing, is the why pump noise is audible. We have two tips to insulate pump housings:

• Soundproofing a build-in hot tub pump
  When the pump is located inside the housing of the bath it is mostylikey that this housing is made of plastic or any other lighweight material. Start by applying Isomat TS to the walls of the housing, on the inside. With these mass loaded vinyl sheets weight is being added which improves the soundproofing of the houseing. You can mount the Isomat sheets on a cleaned surface by useing a contact adhesive. When possible, use some screws on the corners of the Isomat sheets to hold them in place. Next step is to mount a sound insulation to absorb and insulate pump noise. It’s best to use a product with a moisture tight top layer, Merfocell PU for example. Don't forget to seal the seams with PU Finishing Tape.
  
  
• How to make a soundproof hot tub pump housing
  If there is not enough space for insulation products inside the housing of the pump, or if your hot tub came without a decent pump housing, you can make a soundproofed housing yourself. Again, mass is of the utmost importance! Use a thick waterproof plywood, to make a housing out of. Make sure that the housing is large enough, not only for the pump, but also for insulation materials and sufficient ventilation for the pump. If you cannot find a heavy sheet material to build a housing from, you should soundproof the housing with Isomat TS 14 kg/m². Isomat isolates resonances in sheet material, which results in better insulation. For the insulation of sound you best use Merfocell PU.

Points of attention
Always make sure there is sufficient ventilation for the pump. Leave some gaps for hot air to escape, or even better make a sound maze. Use PU Finishing Tape to mask seams when using Merfocell PU. Before using self-adhesive products, make sure everything is well cleaned and free of dust.

Reduce impact noise and vibrations, from a pump
Impact noise is caused by vibrations from the pump, usually perceived as a humming sound. Vibrations can set the housing of the pump in motion or vibrations can be transferred to the neighbour’s house. In order to reduce this, you can use a very heavy MDF panel or, even better, a heavy concrete slab, and bolt to pump to this panel/slab. Underneath this panel/slab you install Regufoam Damper Pads.

Make sure the panel, or pump, cannot transfer vibrations to its surroundings. The weight of the panel/slab should provide enough stability to prevent play on pipes, hoses or tubes and shaking of the pump. If the pump is not stable, which is a real possibility because each hot tub and therefore each pump is different. You can make the Regufoam Pads a bit smaller to gain stability. This way there is less resistance, the slab and pump presses more on the Regufoam Pads, and the whole setup becomes more stable. Always keep an eye out for leaks and stability, this is your responsibility. We have tried to present an application that should work in most situations. You might need to adjust some things to your situation and setup. And as always, just send us an email when in doubt.

How to improve outdoor acoustics
We have also have a guide called 'how to improve outdoor acoustics'. In combination with yet another guide on 'how to make a sound absorbing fence', you can reduce airborn noise, such as speech and music, radiating to and from neighbours. 

Questions?
If you have any questions about this topic, please let us know, we are happy to help you.