If you own a hot tub, you probably get put off by how loud the motor is. I decided to look into how to soundproof a hot tub motor so I could enjoy mine without the distracting noise. Here’s a quick answer:
The best way to soundproof a hot tub motor is to isolate it from the surface it sits on. You can do this with a sound deadening mat or foam to dampen the vibrations. Avoid insulating the motor itself as this could lead to overheating.
In this article, I’ll look at why hot tub motors are so noisy and the best solutions for stopping this problem. All are really easy and possible on a small budget.
Why Are Hot Tub Motors So Noisy?
The hot tub motor is an important part of the whole structure. It powers the pump that circulates the water, along with the heater and the jets. Therefore it does a lot of work.
Often the motor itself isn’t actually that noisy. Hot tub motors aren’t really that powerful because although they do a lot of work, they don’t work on a particularly big circuit.
Generally, the bigger issue is that the motor vibrates, which is what causes most of the noise.
Like all working objects, a hot tub motor loses some of its energy through vibrations caused by the parts moving. It’s these vibrations that are likely the cause of the irritating noise you can hear.
A hot tub motor will sit in a mount inside its casing with circuitry running off to the various parts it powers.
The vibrations caused by the motor transmit into the mount and any other surfaces the motor is in contact with, meaning you can hear them quite clearly while the hot tub is running.
This type of sound wave transmission is called impact noise. The motor’s casing will likely be made from either plastic or wood, both of which are very good transmitters of sound waves.
But it’s likely that another part of the problem will be the motor’s housing acting like an echo chamber.
When sound waves make contact with a surface, part of the wave is reflected, part is transmitted, and part is absorbed. When sound waves can reflect freely inside a hollow space they sound louder than they actually are.
So when it comes to soundproofing your hot tub motor, you’re actually dealing with 2 different issues.
The problem of impact noise is definitely worse, so that’s what I’m going to focus on in this article.
Also, you’ll want to avoid putting too much insulation inside the motor housing. Doing so will also insulate heat, which could lead to the motor overheating and catching fire, something you definitely don’t want to happen.
Things To Check Before Soundproofing Your Hot Tub Motor
It’s completely normal for your hot tub motor to make noise. It should sound like any other motor: a gentle ticking over noise (such as an idling lawnmower or similar).
Before trying to soundproof the motor, ensure it’s not making noise as a symptom of a bigger problem. If you block off the noise before investigating things then you could find a bigger problem in the future when it breaks down.
Listen out for buzzing, humming, screeching and grinding noises. These are all signs of a larger problem.
Buzzing Or Humming
Buzzing or humming noises are a sign that your hot tub pump has seized. You should also find that the water isn’t heating or circulating around the tub.
The best option, in this case, is to completely replace the before it overloads the motor, as this will be even more expensive.
Screeching Or Grinding
A screeching or grinding noise is a sign of bad bearings in the motor. This happens over time no matter how well you care for your system. The more it’s used, the faster this’ll happen.
Again, the solution is to completely replace the motor. Taking it apart to replace the bearings often costs more than an entirely new motor.
How To Soundproof A Hot Tub Motor
Providing you’re happy everything is in working order, you can look to soundproof the motor.
Remember, these solutions are generally designed to isolate the motor from a surface to prevent it from vibrating too loud. As a result, you might not end up with a completely soundproof motor, but the noise level will be drastically reduced.
1. Use a sound deadening mat
This is probably the best option because it’s quick, easy, and delivers excellent results.
Sound deadening mats are designed for use in vehicles to reduce the noise you hear in the cabin. They’re made from butyl rubber, which is an excellent sonic insulator.
Line the bottom of the motor housing with some sound deadening mat, or if the housing isn’t fixed to the floor, sit it on a mat.
Also, consider lining the housing with the product too, as this will reduce the amount of noise that escapes through it.
I’d recommend putting the sound deadening mat on the outside though. It’s designed to also be a thermal insulator and has a reflective foil backing.
Putting it inside the motor housing could therefore trap too much heat and lead to problems.
2. Put the hot tub on a sturdy base
The surface your hot tub sits on makes a massive difference to the amount of noise that comes from the motor.
For example, a hot tub sat on decking can be an issue for a number of reasons:
- Loose slats can vibrate easily
- The empty space under the decking can amplify echoing sound waves
The best surface to put your hot tub on is either concrete or brick. The more solid the surface, the less vibrations can transmit into it.
You might want to also consider sitting the hot tub on some anti-vibration mats (Amazon link). These are similar to sound deadening mats but less expensive, meaning it won’t be a problem to buy enough for your hot tub.
The benefit of this option is that it doesn’t just address a noisy motor, but also helps with noise coming from the pump, heater, and jets too.
3. Enclose the hot tub
If your hot tub is just sat on a surface without any kind of casing, there’s nothing stopping the noise from escaping.
The best solution for this is to enclose your hot tub with a material that’ll effectively reduce sound transmission.
The benefit of this is that you don’t have to focus specifically on the motor or risk insulating it too much.
You could consider sinking the hot tub into the ground, as this will basically enclose it in earth. This will make a massive difference to sound transmission.
Alternatively, build a casing out of something like paving slabs or brick if you want to keep it above ground.
As a last resort, you can build the casing out of wood, but I’d recommend lining it with something like mass loaded vinyl (Amazon) just to increase its mass.
If you don’t want to enclose the whole hot tub, you could just do so on the side where the motor sits. This will stop sound from spreading and will reflect it back into the hot tub housing.
4. Build a soundproof enclosure box for the motor
If your hot tub motor is separate from the main body of the tub and doesn’t have its own housing, you could try building your own.
This is fairly easy to do, and you’ll need the following:
- Medium density fiberboard
- Sound deadening material – mass loaded vinyl or sound deadening mat
- Acoustic foam
- Acoustic caulk
- Glue and nails
All you need to do is:
- Measure the hot tub motor and add a few inches to each measurement to compensate for the materials and some ventilation space.
- Cut your MDF to size; you need a piece for each side and one for the lid.
- Cut holes for ventilation: one in the lid and the other at the back. You can add more holes, but this will reduce its soundproofing ability.
- Glue a layer of sound deadening material down, sealing the edges with acoustic caulk.
- Glue on a layer of acoustic foam, sealing the edges with acoustic caulk.
- Build the box one side at a time, nailing together. Finally, seal the joins with acoustic caulk.
- Sit this box over your motor and you’re done!
This is a fairly easy project and will make a big difference to the amount of noise you hear from your hot tub motor.
The most important thing is to ensure there’s enough ventilation. The motor won’t work too hard, but if you have any concerns then just pop a couple of ventilation fans into the holes.
Some Final Thoughts
Hopefully, this guide has given you some details on how to soundproof a hot tub motor.
The process isn’t too difficult, but I’d recommend focusing on both the motor and the hot tub itself. This will ensure the best results.
Thanks for reading! Check out my recommended products for soundproofing.