Dear Dave,
First on my list is to thank you for ALL of your knowledge. I am wondering why my air conditioners are so loud in my unit and how I can quiet them down? When the air is on I can’t hear my husband talk 15 feet away, or watch television, for that matter. Help. Thank you. —Karen, 40’ 2021 Heartland Cyclone 3713 fifth wheel toy hauler
Dear Karen,
Many women I have talked to would love to have this problem! 😆
There is very little maintenance that can be performed on a fan or motor, which is the only moving part of your roof air conditioner. However, there are some modifications and items to inspect to quiet the typical noisy roof air.
Troubleshooting the roof air conditioner
The first thing I always suggest when trying to troubleshoot the roof air conditioner is to get exact readings for temperature and air flow. This can be done with an anemometer, available on Amazon here.
This will tell you the temperature coming out, and the airflow, or CFM, which is helpful if you need to contact Keystone Customer Service.
Another tool I use is a decibel meter that will give precise readings for noise levels. You can find one on Amazon here.
Take inside vent cover off
Next, I would take the inside vent cover off and inspect the air return area and the outgoing air. When the thermostat calls for cooler air, the motor starts and turns the fan, which draws the warm moist air from inside your rig through a filter into the air return and is pulled through the evaporator coil. Make sure the filter is clean and not obstructed, as well as the evaporator coils. Any obstruction will limit airflow and make the unit work harder with higher amp draw, which could make the compressor shake more.
Here is a unit tipped on the side to show the air return on the left and the ducted air on the right, which has the squirrel cage or fan. Check to make sure the fan is not loose or has a broken fin which could be hitting against the side of the unit. You can even run the unit with the cover off to verify it is working properly—just keep your hands out of the squirrel cage area.
Check mounting bolts
If everything looks to be operating properly, check the mounting bolts at the four corners. These need to be tightened periodically as the gasket between the roof air and the roof can become compressed. Consequently, the unit will not be tight and cause vibration or chattering. Most manufacturers have a torque setting. However, I have found just giving them a good tightening with a hand socket is sufficient.
Next, check the incoming and outgoing ductwork, as most air conditioning companies provide a generic baffle that the manufacturer must cut to the appropriate size and install it with HVAC tape. I have found several that have come loose and provide inadequate airflow and vibration. Any loose material in this area will amplify airflow noise and vibration. You may need to “customize” this area with additional tape and even some additional insulation.
There is a product that has been customized for the roof air conditioner that not only provides superior airflow, but also insulates for quieter air distribution by 3 decibels.
You can find it on Amazon here.
You might also enjoy this from Dave
How can my RV’s roof air conditioner run more efficiently?
Dear Dave,
I’d like to improve the efficiency of our roof air conditioner. The factory shrouds are black. I’d like to paint them white. Second, I’d like to insulate the pipe from the compressor to the evaporator. Thanks. —Joe, 2019 Coachmen Pursuit
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
Read more from Dave here.
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RVs are designed for profit, so cheap air conditioning units that make a lot of noise are perfect.
I rarely use my AC but tend to wear noise canceling headphones if I have to.
There are plenty of free sound measuring apps for phones. They’re not highly calibrated but work well.
If there is a loud thumping noise and vibration that wasn’t there last season or after a few weeks of non-use, check for a dirt dauber nest on the outside fan and the squirrel cage blower. Been there done that. It got in apparently thru a small drain slot. Cant remember the details but I did something to mitigate little critter entrance after that.
Or, make sure the next rig you buy has ducted air.
If we try to lower the temp more that one degree on the thermostat the A/C kicks into high fan. Try adjusting your thermostat one degree at a time to keep it on low fan setting. That may be the issue. Good luck!
Not sure why manufacturers aren’t installing mini-splits instead of the traditional rooftop RV units. Mini-splits are super quiet, efficient, and use less energy. Installed one on my campervan running off my solar power system. A/C and heat on mine. Check out the YouTube videos.
It’s not part of what’s promised when you install a Soft Start unit, but I did find that my rooftop AC was definitely quieter after the installation.
You missed the boat on silencing your RV AC unit, Dave. Here’s the unit I bought at a rally a year ago and installed in our coach. It made a HUGE difference in the racket from that AC unit. I would recommend this first and foremost…
https://wackoproducts.com/product/dometic-rv-a-c-silencer/
Also found it odd this mod wasn’t mentioned. We have one of these kits ( wacko) and find it does quiet it down.
I will give one warning though with the kits
new cover , it hangs down about a inch more than the original one . That may or may not matter depending on your application. In our case it will hit the slide. We simply remove the cover before running the slide in .
We truly enjoy watching Changing Lanes YouTube videos (Tara & Chad know their stuff & have earned our trust). After watching their video…https://changinglanesrv.com/testing-two-rv-ac-upgrades/ we immediately ordered an AC Silencer. Simple to install, and it really helps! My husband goes to bed earlier than I do and, in order to not wake him, I would have to turn on the tv’s closed captioning because of the ac noise level. No more! The silencer comes from Canada (their website converts currency), but we got it within a week.
I have a 15,000 btu Dometic Brisk II a/c thats very noisy. It’s a piece of junk thats why it’s so noisy. I would not buy another RV that has anything Dometic in it. Jayco dealer said thats the way the a/c is. There is a company that makes WackO Products DA100 is an air conditioner silencer kit. Not sure how good it works. But in reality a/c should be quite with out having to buy a kit to silance them.
It works beautifully. Made a huge difference in our coach. Go for it!
The dometic on mine is awful. I’ve tried everything. Even outside it’s so loud it’s embarrasing to have it on sometimes. Ridiculous they can’t make something decent to use. If I had a large trailer I’d seriously look at mini-splits. Use for my condo and hardly hear it when running. Can go by the outside compressors and if all 8 there are running you can still have a normal conversation standing there. There’s a market out there for good ones.
We had a noise problem with ours. You could actually feel the ceiling vibrating. I checked to make sure the shroud vibrating was not the problem, put some high density foam under the shroud and reinstalled it. Still had the problem so I removed the inside cover. All looked good. Finally checked the mounting bolts. Tightened each of them a full turn. Stopped 80% of the vibration and noise.The
AC unit is mounted to a big piece of plywood that enhances the noise and acts like a speaker.
I have found that cleaning the fan blades helps quiet down the A/C’s. I try to clean my fans every winter along with other maintenance.
And if those suggestions don’t work, you get a set of noise cancelling headphones from Amazon like the ones shown here……