An easy upgrade takes the growl out of ducted air conditioners

RV A/C Silencer info graphicRooftop air conditioners revolutionized the industry and made camping locations more pleasurable and accessible at times of the year when an RV would otherwise be unbearably hot. But along with the comfortable temps an A/C unit can bring, there is one annoying drawback. They tend to be somewhat noisy in operation. Maybe not on the order of jet-engine loud, but annoying enough to make sleeping difficult, watching TV bothersome and even conversation seem like a shouting match. Sure, you could sleep with a pillow over your head or turn up the TV volume to drown it out, but you shouldn’t have to.

The folks at WackO Products came up with a solution to make that A/C unit not only quieter but more efficient. Dubbed the RV A/C Silencer, it consists of a replacement for the factory return-air cover. Once installed, it redirects the cabin’s return air through a padded chamber and channels the cooled outgoing air exclusively to the A/C ducts, resulting in quieter overall operation. It also replaces the foam filter found in most units with a durable, washable filter sandwiched inside a frame that does a better job of filtering the return air and containing sound inside the A/C unit, noticeable just by comparing the two filters side by side.

Available in two models to fit popular Dometic and Coleman-Mach ducted systems, the RV A/C Silencer was easy to install and made an appreciable improvement in sound reduction on a 15,000-Btu Dometic A/C unit inside a Winnebago Minnie Plus test trailer. There was no noticeable loss of airflow from any of the registers in the trailer. In fact, the air through the registers in the bunkroom, which are farthest from the rooftop unit, seem to blow just a bit stronger than before.

The original return-air cover extended from the ceiling a little more than ¾ inch, compared to about 2½ inches for the WackO RV A/C Silencer counterpart. Despite being more than twice as thick, it is not obtrusive unless you have a low ceiling height and/or tall people using the RV.

The only drawback is that you lose the ability to distribute cold air directly from the A/C unit by opening the slider in the factory cover, which will probably be a negligible inconvenience for most RVers. Overall, we were impressed by the quality of the product and ease of installation of the kit.

Quiet Time

A decibel-meter app on a smartphone was used to verify the reduction in air-conditioner noise with the WackO RV A/C Silencer installed. While the product did not completely “silence” the operation, it did quiet it down enough to make watching TV, conversing and sleeping a lot more enjoyable.

The sound level was measured at 53.6 decibels with the A/C off, 62 decibels with the A/C on and the original Dometic return-air cover still in place, and 56.2 decibels with the WackO RV A/C Silencer installed.

It may not seem like much, but a nearly 6-decibel reduction in a space of less than 100 square feet is very noticeable. Sound-level measurement is exponential so even a reduction of 1 decibel can be significant. It was even more remarkable that the sound level with the A/C on and the WackO A/C Silencer in place was only 2.6 decibels louder than when the A/C was turned off.

Headshot of author Rick A. DiazResiding in West Palm Beach, Florida, Rick A. Diaz is an avid mountain biker, woodworker and former Hollywood, California, custom Harley-Davidson shop owner, as well as a motorcycle and truck journalist. Rick will be taking his fiancée, their two retired racing greyhounds and an Italian greyhound puppy on adventures in their Winnebago Minnie Plus while contributing to Trailer Life.


  1. Well, you lost me when you covered up half of the air output. That is where most of the cooling comes from in the living area. Of course, about half of the noise also. It would have been interesting to see the decibel reading with the original cover, with the outlet closed off. I agree the noise is annoying, but for $200 and half of the airflow, I’ll pass.

    • Rick A. Diaz replies: The RV A/C Silencer does nothing to reduce air output. The WackO design simply changes where incoming air is drawn from and does not block the air output via the ducts in any way. As was mentioned, we no longer have the ability to direct the output straight down from the A/C. Since we prefer to use the trailer’s internal ducts anyway, this was a negligible trade-off. The decibel-meter reading of 62 was with the OEM cover on and the air directed to the ducts with the internal outlet closed. That compares to the reading of 56.2 with the WackO Silencer in place and blowing through the ducts, which is how we always use our A/C. For $189, all we lost was the excessive noise, and recent trips with the trailer have shown this to be a more than worthwhile investment.

    • Rick A. Diaz replies: I placed the phone with the decibel meter app atop the divider between the dinette and theater seats as this was a good “listening” spot for either conversing while eating or watching TV. This exact location was used for every meter reading so that the results would be as accurate and consistent as possible given the environment and quality of the test equipment. Our results did closely reflect the testing WackO provided us of its own product testing.

  2. It sure seems expensive for what you get, and by taping over a designed outlet you are varying from the design flow of the unit. Yes, you say more comes out the other vents, but the pressure is increased, not good for the unit. On top of that, your return filters inhibit the normal return airflow, again increasing the pressure on the system, possibly shortening its life. Even with all this, if it were half the price I might consider a purchase as we have a small travel trailer.

    • Darrell from WackO Products replies: Dometic and Coleman make ceiling assemblies with and without the cold-air-dump feature. Therefore, taping or blocking that airflow and pushing it down the ducts exclusively is not inhibiting anything. If we were restricting airflow, either intake or output, we would not see an airflow increase from our product like we do. Dometic has expressed no issues with our product.

  3. Good idea to make the RV air conditioner quieter. I’m really uncomfortable when I sleep because it’s very noisy. Thanks so much! I will try it!


Please enter your comment!
Please enter your name here