Loud Radon System? Install A Radon Noise Suppressor - American Radon Mitigation

Loud Radon System? Install A Radon Noise Suppressor

Is Your Radon System Too Loud? Install A Radon Noise Suppressor

Is your radon system loud? Can you hear your radon system on your deck or patio? A noise suppressor can help quiet your radon system.

If you have a radon fan that is moving a lot of air or a high-suction radon fan such as a RadonAway RP265, Fantech RN4, AMG Eagle, or Eagle Extreme, the noise from your radon system may be even louder.

In this example, we have a mid-range radon fan, an AMG Maverick, moving 60 cfm of air. It’s not super loud, but loud enough to be annoying in some instances. This radon fan is in the garage attic, and the pipe vents out through the roof.

To start, we will get a baseline of what the radon system sounds like without a noise suppressor. Click here to listen to what the system sounds like without a noise suppressor.

Then, we will add a noise suppressor to hear the difference in the noise levels. The noise suppressor changes the tone of the discharge noise quite a bit. You can still hear it, but it is a lot quieter. When approaching the radon system on the roof, you can barely hear the system when the noise suppressor is installed. Click here to listen to what the system sounds like with a noise suppressor.

Now, it is time to choose which noise suppressor to use.

Some of the links in this blog are affiliate links. This means that if you click on the link and purchase the item, we will receive an affiliate commission at no extra cost to you. All opinions and recommendations remain our own.

Our website offers 3 options for purchase

Outdoor Noise Suppressor: This noise suppressor is for outdoor radon systems and is an all-PVC option.

Outdoor Noise Suppressor

Outside Radon System with Noise Suppressor

Attic Noise Suppressor—Short: This noise suppressor is about 13″ tall and is designed for use in a house or garage attic.

Attic Noise Suppressor Short

Attic Noise Suppressor—Medium: This noise suppressor is about 18″ tall and is designed for use in a house or garage attic.

Medium Attic Noise Suppressor

Selecting An Attic Noise Suppressor Size

If you are installing a noise suppressor in the attic, you will need to start by measuring from the fan to the roof. This will help you determine whether you have enough clearance to use the Attic Noise Suppressor—Medium at 18″ or the Attic Noise Suppressor—Short at 13″. In the installation example below, we have the clearance to use the medium attic noise suppressor.

Attic Radon System

Measuring The Radon Fan Duct Diameter and Pipe Size

It is also important to measure the duct diameter of your radon fan and the pipe size of your radon system. All noise suppressors have a 4.5″ opening on both sides.

Depending on the radon system’s fan duct and pipe size, additional rubber or PVC reducers may be needed. These can be ordered from Amazon or purchased at a hardware store.

Radon Fan Duct Diameter 4.5″

For example, the AMG Maverick has a 4.5″ duct opening, which is the same size as the opening on the bottom of the noise suppressor. This allows the noise suppressor to mount directly to the fan.

Radon Fan Duct Diameter

Noise Suppressor on 4.5" Duct Fan

Radon Fan Duct Diameter 3.5″

Many high-suction fans have a 3.5″ fan duct diameter. This will not work for directly installing the noise suppressor to the fan because the noise suppressor opening is 4.5″, so it would be too large.

We recommend using a four-to-three rubber-reducer bushing.

The rubber bushing would be installed to the fan duct opening, allowing the noise suppressor to fit over it.

Noise Suppressor on 3.5" Radon Fan Duct

Alternately, you could use a three-to-four rubber coupler mounted to the fan duct opening, a short piece of 4″ pipe, and then mount the noise suppressor to the pipe.

Noise Suppressor on 3.5" Radon Fan Duct

Radon Fan Duct Diameter 6″

For a 6″ radon fan duct diameter, you would use a six-to-four rubber coupler and a three-inch piece of 4″ pipe. An inch of pipe would go into the rubber coupler attached to the fan, and two inches of pipe would go into the rubber coupler attached to the noise suppressor. It would sit tight, as shown in the image below.

Noise Suppressor on 6" Radon Fan Duct

For additional examples, check out this video.

4″ Radon Pipe

The noise suppressor is designed for a 4″ pipe, so no additional fittings are necessary.

3″ Radon Pipe

If the radon pipe is 3″, you can use a PVC-reducer bushing that reduces from a four-inch outside diameter to a three-inch inside PVC diameter. Glue the reducer bushing inside the top of the noise suppressor to accommodate the 3″ pipe. 

PVC Reducer Bushing


Tools Required for Install

  1. Saw
  2. 5/16″ Nut Driver or Flat Blade Screwdriver
  3. Level
  4. Tape Measure
  5. PVC Primer
  6. PVC Cement


Start by unplugging the radon fan.

Then, loosen the clamp on the rubber coupler that attaches the pipe to the top of the radon fan.

Next, twist and push the pipe up. Once it has cleared the fan, gently pull the pipe down to disconnect it.

Disconnecting Radon System Pipe from Fan

Measuring and Cutting the Exhaust Pipe

First, mock up the noise suppressor by placing it on top of the fan (do not secure it in place yet).

Mockup Noise Suppressor for measuring

Next, measure the amount of pipe needed to exhaust the radon system. The current radon code says the radon pipe should exhaust a minimum of 1 foot above the roof. To measure, hold the tape measure 1 foot above the roof and measure down to the bottom of the noise suppressor coupler. In this case, we need 28″ of PVC pipe. You can reuse the pipe you removed by cutting the pipe down to the measurement that was just taken.

Measuring New Radon Pipe Length

Gluing The System Together

Start by removing the noise suppressor. Next, glue everything together. 

Start with PVC primer and prime all the PVC bushings and pipe according to manufacturer recommendations.

Then, glue everything together using PVC Cement. The manufacturer recommends giving it about a quarter turn as you push the pieces together to be cemented.

Putting The System Back Together

Once the bushings, pipe, and noise suppressor are glued together, push them gently through the flashing, being careful not to cut the rubber lip.

Reinstalling the Radon Pipe with Noise Suppressor

Line up the bottom coupler of the noise suppressor with the top of the radon fan. Twist as you pull down and fit the coupler in place so it does not pull the rubber gasket in the roof flashing down. If the gasket is pulled down, it could leak. Visually inspect that the rubber gasket is not pulled down and is pulled up tight around the pipe.

Roof Flashing Not Installed Properly

Roof Flashing Installed Properly

Once everything is in place, use a level to plumb the radon fan before and as you tighten the clamps in the next step.

Using the 5/16″ nut driver or flat blade screwdriver, tighten up the clamps to secure the noise suppressor to the radon fan.

Do not skip the gluing or tightening steps; otherwise, the system may leak.

Glue and Tighten In Place

Finally, plug the radon fan back in, and your installation is complete.

Final Result

You can now enjoy a quieter radon system. Click here to listen to the final result.

To purchase a noise suppressor for your radon system, visit our Radon Shop.