Dometic AC noise reduction

[Just Joe]

We don't use our AC very often, but when we do it would be nice if it didn't scare the dog and stess-out the cat. I didn't want to buy one of the newer (quieter) models just yet, so I looked into how I could insulate the stock Dometic unit better and achieve a noticeable reduction in noise. It took a 3-step approach, but I got it down to 65dB which is a significant reduction from the 75+dB level before. I took the attached dB reading in the center of our LE2 right under the front of the AC unit. I have attached photos of the 3 items that I added; (1) dense foam insulation to fill the hollow area to the rear of the return air intake vents between the roof-top unit and the ceiling panel, (2) I added a .4" layer of stick-on foam insulation over the very thin layer that came on the inside of the ceiling panel along with another piece of dense foam between the the center sliding vent cover (which is right below the fan motor) and the added layer of foam insulation (I did this so the cool air would be directed out the 2 side vents, and the front and rear vents instead), and (3) I installed an AC compressor noise reduction blanket. We are very happy with results!!! Joe/769

[Patriot]

@Just Joe

We chose not to continue with the noise level of the Demonic Penguin and moved on the Truma Aventa Retro fit professionally installed by Oliver. We could not be happier. With your handy work, hopefully now you can listen to music, talk on the phone and even watch a movie.

Necessity is the mother of invention, nice work! 👍🏻

 

[topgun2]

I've watched a number of YouTube vids on how to lessen the A/C noise of RV A/C units.

Your approach looks similar to many - a combination of sound deadening materials plus smoothing the airflow inside the unit.

 

Nice job with nice results.  Thanks for posting this.

Bil

[MAX Burner]

@Just Joe - Great move, Joe!  Will do something similar to our "After-burner Penguin" before our next trip.  Thanks for posting your optimum results....

[Ray Kimsey]

@Just Joe  I have done something similar but have never added the compressor blanket and was wondering if it did much and where you got it. Thank you! Glad it worked for you. My current sound level is 65db.

 

[Just Joe]

The compressor does make a little extra noise that the blanket helped to dampen a bit. However, it made the least amount of difference of the three things that I did, but every little bit helps! The attached blanket is the one that I used. It was a challenge to get it wrapped around the compressor. Joe/769

[Ray Kimsey]

@Just Joe  Thank you for the information. I will give it a try!

[JDB_Traveler]

This is great info and something I want to try before moving forward with a unit replacement, a 10dB reduction is huge. Two questions, 1) regarding the additional piece of dense foam added between the center sliding vent cover (which is right below the fan motor) and the added layer of foam insulation. Are you saying it was added under the .4" layer of stick on foam and was it cut to match the shape of the vent.  I have not yet removed the grill so I don't know what things look like yet and 2) is all the work done from inside the trailer, especially wrapping the compressor?  The dB reduction you achieved is at the medium setting of the Truma Aventa unit. I would appreciate and additional details you can provide.  

[jd1923]

Been working in the Oliver afternoons, shore power connected with AC on. Loud as a diesel truck and on-n-off it starts singing. Must be fan bearing going. Will replace with any non-Dometic model before travel this fall. It is and sounds like an albatross! I would not spend a penny on it. 

[Just Joe]

Yes, the foam insulation was added in the indentation under the stick-on foil covered insulation. It was cut to fit the area where the sliding vent is located. All the work was done from inside the camper except the compressor blanket which is installed under the exterior AC cover. It's too bad that the Dometic unit only has a two speed fan motor; a lower speed setting like the Truma unit has would likely reduce the sound below 60dB. Joe/769

[In Pursuit]

Great job Joe, I will tackle this project in the up coming week.

[Skipster]

A friend of mine installed a mini split on his big Rv     And you can hardly hear it.   Why can’t Oliver figure out how to install a quiet ac . we can not use ours because of the overwhelming noise

Edited July 7 by Skipster
No reason

[In Pursuit]

Is it safe to cover the compressor with a blanket? 

[jd1923]

2 hours ago, In Pursuit said:

Is it safe to cover the compressor with a blanket? 

No, too much insulation in some of these mods will produce too much heat  retention and bearings or seals will fail over time.

[CRM]

14 hours ago, In Pursuit said:

Is it safe to cover the compressor with a blanket? 

That's a question for the manufacturer of the AC unit. Many make optional compressor blankets for their units to reduce the sound level when needed and since the compressor is cooled via the refrigerant it usually isn't a problem to run one. A problem can occur though if it affects the flow of air through the condenser coils.