How to make a whole house fan quieter: DIY guide

A whole house fan is installed in the ceiling near the center of the house, the central hall way in most cases. The fan operates very close to the living areas so it can be very noisy. In addition, these fans are pretty powerful, their CFM rating is usually 2-3 times the indoor area, so the noise they make can be really annoying.

However, loud whole house fans are a thing of the past. With the advent of technology, there are now units that are as quiet as a whisper. Here is a good list of whisper-quiet whole house fans for your reference.

How to make a whole house fan quieter

Nevertheless, if you have an old whole house fan that is noisy here are some steps to make it quieter;

1. Run the fan at the right speed

Most whole-house fans come with multiple speed settings. These fans do not need to run at its top speed for the whole time. The best practice is to start the fan at its highest speed when the house is hot. Running the fan at this speed will cool the house faster, and after 30 minutes or so, your home will get cooler. Once the house is cooler you can switch the fan to a lower speed.

Running the fan at a slower speed will considerably reduce vibrations which is the main source of the noise. It will also reduce the airflow thereby further reducing noise.

2. Use vibration dampeners

Improper installation of whole house fans is the reason behind the bulk of its noise. Proper installation and using dampeners between the mountings can significantly reduce vibrations.

Many whole house fan models which are designed to be quiet are actually freely suspended from the rafters. They use an insulated duct connected to the ceiling via a damper box to draw air from inside the house. The free suspension cuts off any vibrations the fan has and thus eliminates any chance of noise.

3. Make sure that the fan is perfectly balanced and that the blades are in proper shape

One most common reason for noise from old whole house fan models is an unbalanced fan. This can also be caused if the blades are not in their right shape ie if they are bent. This often happens with cheaper models as their build quality is relatively low.

An unbalanced fan will cause vibrations and noise, especially at high speeds. The only solution to this is to balance the fan. However, balancing a whole house fan by yourself is not that easy as you will have to dismantle the fan first. Hiring professional help is also not worth the money as you can, often buy a new whole house fan for that money. My advice would be to go for a new fan if it wasn’t a costly model. If you are buying a new fan make sure to go for quiet models.

4. Make sure that you have enough attic ventilation

Attics are required to have a venting area of 1 sq. ft for every 300 sq. ft of attic space. Since whole house fans pump the air into the attic it is important that this air is vented easily. If the attic doesn’t have enough ventilation the whole house fan will create a positive pressure inside the attic, and also this can lead to a whistling noise which is really annoying.

5. Reduce shutter noise by replacing it with a good damper box

The good thing about damper boxes is that they prevent the air from backflowing into the living areas from the attic space. Most of them have a double door mechanism which is very quiet. But most old whole house fan models use shutters that open and close with airflow, which works like a damper box but they make a lot of squeaking noise which is annoying.

Unfortunately, not all whole house fans are compatible with damper boxes. If that is your case you can reduce the squeaky noise of the shutters by lubricating them with some oil or grease.

How to DIY a quiet whole house fan

As mentioned somewhere above there are some good whisper quiet whole house fans but they are priced in the range of $700 to $1000. Is there any way to make a quieter one by yourself? Yes, you can make such a whole house fan for less than half of that money!

Before we begin let me tell you what all quiet whole house fans have; they are all ducted type where the fan is freely suspended in the attic from the rafters. As the actual fan is away from the ceiling and in the attic, there isn’t much noise you can hear from the house. So that’s exactly what we are going to do here, we are going to make a ducted whole house fan using an attic fan.

Attic fans are different from whole house fans, they are used to vent the attic. However, if you can use the same fan to suck the air from inside the house through a duct, it becomes a whole house fan!

So here are the things we need;

  1. A QuietCool attic fan – https://amzn.to/3oaQ9a7Opens in a new tab.
  2. An insulated ducting – https://amzn.to/3ocYD0tOpens in a new tab.
  3. A ceiling register box – https://amzn.to/3odOQqQOpens in a new tab.
  4. A duct reducer – https://amzn.to/33wq6lZOpens in a new tab.
  5. A vent cover – https://amzn.to/3lvJSnEOpens in a new tab.
  6. A backdraft damper – https://amzn.to/3fUhnPmOpens in a new tab.
  7. Electrical wire – as required
  8. Duct tape – as required

I guess you already know what to do. The reason for choosing the QuietCool attic fan is that it is really quiet. Since you are going to make a quiet fan I don’t see any reason to buy a noisy fan.

Please note that it is the size of the fan that is important here, make sure that the fan you buy is of the right CFM. Here is a guide to sizing whole house fans for your reference. Once you buy the attic fan change the dimensions of the rest of the items accordingly.

Step 1: Connect the attic fan and the duct reducer using duct tape. The fan here needs a 16 inch duct but we are using one that is 12 inches. So we are using a 16 to 12 inch reducer.

Step 2: Connect the 12 inch end of the reducer to the insulated ducting using duct tape.

Step 3: Connect the other end of the insulated duct to one end of the back draft damper

Step 4: Cut a 12 x 12 inch hole in the ceiling and install the ceiling box. Use the vent cover to cover the hole from below

Step 5: Connect the other end of the back draft damper with the ceiling box

Step 6: Make sure that all the parts are well connected without any air leakage

Step 7: Carefully suspend the fan and the duct from the rafters of the attic.

Step 8: Make the electrical connections to the fan

And we are done! Now you have a quiet whole house fan for half the cost of a pre-built one.

Charles John

A novice DIYer who learns about home ventilation. I am a mechanical engineer and have a basic knowledge of HVAC systems but I learn continuously to make myself the best blogger in that space.

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