Unfortunately, noisy air vents typically indicate a bigger HVAC problem that needs to be taken care of. There are a few simple steps that you can take to fix the issue, but, in some cases, dealing with the root cause of the problem might require initiating a bigger project.
Start with opening up the vent dampers, checking the flexible ducts for kinks, changing the air filters, and replacing the vent cover.
If that didn’t make the air vent quieter, you might have to install duct liners to soundproof the system.
If high static pressure is causing the noise, make sure to call in an expert. The professional might recommend installing larger ductwork, adding a bypass duct, or expanding/adding registers and grilles to deal with the noise issue.
Below you will find step-by-step instructions for the DIY solutions and a few helpful tips.
How To Fix Noisy Air Vent In Bedroom?
The first thing that you should do is make sure that all the basics are taken care of.
- Open up all the vent dampers. Closed vents make your HVAC equipment work harder as they reduce airflow. By opening all the dampers, you’re balancing the system out and simultaneously getting rid of the extra noise.
- Check your flex ducts. If you have flexible ductwork installed, ensure that these parts of the system are not bent. Kinks will increase static pressure and that, in its turn, can create unnecessary noise.
- Clean the HVAC system. Dust buildup inside the equipment can reduce airflow and make your system noisier. The actual ductwork can be cleaned once every few years, while the filters have to be replaced regularly (every 30-90 days).
Read: How To Fix Insulation Blowing Out Of Air Vents?
If you have a filter installed in your air vent, then the vent will become noisy once the filter gets clogged.
All you would have to do is open up the air vent and install a new filter or clean the existing one.
When inserting the filter back in, make sure to install it in the right position (the element has arrows that will guide you). Also, you might not want to go for extra thick filters or those with a high MERV rating as they can block the airflow.
Read: Does Closing Air Vents Help Cool Other Rooms?
You can try replacing the grille.
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Choose a vent cover that is going to fit right into the opening. Go for one with a different grid pattern and make sure that it’s made out of aluminum.
Steel resonates a lot easier than aluminum, as well as the grilles with long blades. So, if you switch the old vent cover to a new aluminum one with a square grid, you might be able to significantly reduce the noise.
Upgrade to a variable-speed blower. This is the perfect solution for those who are already planning on replacing their existing HVAC system.
Single-speed blower motors can only function at full power. They regulate the temperature by constantly turning the unit on and off.
A variable-speed blower, in its turn, is able to run at a slower speed. Such an element will improve the efficiency of your heating and cooling system, and it will become a lot quieter.
Read: Why Dust Coming Out Of Air Vents?
How to Install Duct Liners?
If you have inspected the system and there is nothing wrong with it (apart from the noise), then you can choose to install a duct liner directly in the air vent.
Unlike insulation, duct liner is used to line the inside of the duct. Some liners offer condensation control and protection from energy loss, as well as vibration damping and sound absorption.
If the latter two are your priority, then look for a duct liner that is able to absorb a range of different sound frequencies. This feature is measured by the noise reduction coefficient – NRC. The higher the coefficient, the better the sound absorption.
You might also want to look for a material that is non-particulate (does not release any fibers in the air) and has antimicrobial properties.
Do bear in mind that even though duct liner installation is a relatively simple DIY project, you would still have to consult an HVAC expert about the right thickness of the material. If the liner is too thick, it might reduce airflow.
Read: Can An Attic Be Used To Vent A Portable Air Conditioner?
What You’re Going to Need?
- The actual duct liner (ideally, you would want to go for a product that already has an adhesive layer for easy application)
- Retaining clips
- Measuring tape
- UL 181 tape (this is the right kind of tape to use on rigid ductwork as it provides a high-performance permanent bond)
- A multi-cutter
- Measure the duct walls and cut out the duct liner.
- Some liners that have an adhesive layer have to be activated with water. Once the layer has been activated, simply place the pre-cut piece onto the duct walls and apply a bit of pressure to make them stick.
- To secure the liner in place, use retaining clips.
- Apply a UL 181 tape over the retaining clips to provide a vapor barrier. Use the tape to also cover the frame and the edges of the duct.
- Apply a sealant over the seams between the sections of the duct liner.
How to Deal with High Static Pressure?
In a lot of cases, the HVAC system will become noisy if the ducts are unable to accommodate the volume of air that the system is trying to move. High static pressure will make the sound of the air circulating through the unit more audible.
The simplest thing that you can do is adjust the fan speed. If initially, the speed was too high, you can reduce it to see if that helps with the noise issue.
If this fast solution did not work, then you might have to:
Sometimes, the existing ducts are way too small. Installing larger ductwork (especially, in the area around the blower) will help reduce static pressure.
Add a bypass duct
If you have a zoned HVAC system, you can benefit from a bypass duct. This element connects the supply plenum to the return ductwork which helps reduce overblow and noise issues.
Expand or add registers and grilles
The majority of houses, do not have enough return air. If that’s the case, the HVAC system will be constantly overworking as there is a lack of airflow. This will also lead to insufficient heating or cooling.
Increasing the size of the grilles that are already there or adding new registers is one of the ways to help the system out.
Ideally, you should leave the job to a professional as only an HVAC expert can calculate if your existing system will be able to handle such an add-on.
If your HVAC system has been sized and installed correctly, then the chances are high that you’ll be able to fix a noisy air vent in the bedroom by simply changing the filter or opening up all the vent dampers.
If the root cause of the noise is high static pressure, then you would have to invite a professional over to install larger ductwork or expand the existing registers.
Finally, you can try soundproofing only the noisy air vent by installing a special duct liner.