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How To Wire A Duct Booster Fan To A Blower? [2 Simple Steps]

Duct booster fans help an HVAC system ensure good air quality in your house. Unfortunately, they sometimes get defective. But hiring a professional might cost a lot. So you’ve to tweak and wire the booster fans yourself. 

How to wire a duct booster fan to а blower by yourself?

First, remove the floor covering to expose the main cover. Then you’ve to detach the fan beneath it. When that’s done, carefully pull it out. Get a new booster fan of the same size and screw it tightly. If the booster fan doesn’t fit, you’ll have to install a bigger duct boot. 

This is the brief documentation of the entire process. We’ve discussed each of the steps in simple words with a lot of details. 

Read along if you wish to know more about the process and do it yourself!

Importance of Duct Booster Fans in An HVAC System

It’s not possible to understand the booster fans without knowing about the HVAC system. 

In simple words, an HVAC system makes your house feel more comfortable. The air will also be more breathable. 

But what role do duct booster fans play exactly? 

A duct booster fan simply increases the airflow inside the ducts. In most cases, it’s installed around in the middle between a vent and a blower. Without it, both heating and cooling systems will fall apart. 

That’s why a great HVAC system is never complete without a good duct booster fan. It also reduces overall energy bills significantly.

For example, a great cooling system will cool down your room rapidly. Simply put, the better an HVAC system, the lower your electric bills will be. 

This is why you can’t just ignore any sort of malfunctions at all. Whether it’s a duct fan or adding a vent in ductwork, you’ve to fix them.

How to Wire A Duct Booster Fan in 2 Steps?

If you’re still here, now you surely know how important the wiring is. Let’s not wait around any more and head right into the installation process. 

But before you begin you’ll need a couple of tools- 

  •  Screwdrivers
  • A Duct Booster Fan 
  • Duct Tape

This section covers the installation where the booster fan completely fits. We’ve also discussed what to do when it doesn’t fit right after. 

Step-1: Remove the Cover and Old Booster Fan

Pull the floor covering back where the fan is installed. Just simply hold the cover and pull it back. This will expose another floor covering right below. 

Unscrew the lower cover with the screwdriver later on. When that’s done, you should be able to pull the booster fan out. 

This is also a great time to inspect the ducts if you want to. Knowing when to clean the ducts can significantly improve cooling results. If it’s dirty, you can just replace the air filter. 

Step-2: Installing a New Duct Booster Fan 

It’s normally a wise move to buy the booster fan after you uninstalled it. Because that way you can always match the size. 

Anyways, get the new fan and gently place it in the duct boot. These fans also have grilles of their own. 

Pull the wires through the grilles in a way that doesn’t block the fans. After that, just connect the booster fan to a power source. 

That’s how easy it is! Now, place the cover back and tighten the screws. When that’s done, place the floor covering back in its place. 

Don’t know where you can find good quality duct booster fans?

No worries! Here are some of our top picks regarding duct booster fans- 

Product 1
Product 2 

Just choose whichever you like and get started! 

You can even connect a duct board plenum to an air handler for better results. But duct booster fans are a fairly cheap alternative.

How To Wire A Duct Booster Fan That Doesn’t Fit?

Fitting a booster fan is easy but what about the situation where a fan doesn’t fit? In that case, you’ve to take some “extreme” measures. But don’t worry, these are easy too. 

Here’s what you’ll need-

  • A Jigsaw
  • A Circular Saw
  • A small saw
  • A Duct Boot
  • Foil Tape 
  • Screwdriver

Manage these tools as soon as you can to get started!

Step-1: Cut Open the Floor Covering 

Like before, you’ve to remove the floor covering to expose the main cover. After that, you’ve to cut open a good portion of it. 

The best method is to cut open the entire cover from one joist to another. This will reveal the entire duct connection and make the installation easier.

To achieve this, take the circular saw and cut it out. 

Step-2: Remove the Old Duct Boot & Install a New One

It’s time to get the screwdriver and unscrew the metal sheet. The old boot will come off easily once fully unscrewed. This will reveal the register hole.

You’ve to enlarge the register hole now. Take measurements and use a small saw to do it efficiently. 

Attach the new boot and tighten those screws later on. Use some foil tape to properly seal and insulate the connection. This process is the same as insulating ductwork under the basement

With that out of the way, you can now put back the floor cover that you cut. That’s it! You have just installed a bigger duct all by yourself! 

You can now easily install a bigger duct booster fan peacefully.

To be fair, all of these can seem too hard and time-consuming for you. In that case, you should hire a plumbing service. Because they can fix this issue easily for you. 


Question: Where should a duct booster fan sit?

Answer: A booster fan should always sit between a ventilation room and an AC. The placement is quite strategic (length-wise) and doing it right will significantly improve the cooling. 

Question: Are duct booster fans worth it?

Answer: Yes, the duct booster fans are totally worth it because they’re cheap. If you compare duct booster fans with air handlers, they won’t stand a chance. But for a budget alternative option, booster fans are very alluring and hard to ignore. 

Question: Why are some of my vents not blowing air?

Answer: The most probable reason is a dirty air filter. You’ve to replace it as soon as you can. But if replacing a filter doesn’t work, you can install or replace the old booster fan. It’ll immediately improve your overall airflow in the vents. 


That was everything we could gather on how to wire a duct booster fan to a blower. We sincerely hope you’ve found the information that you were looking for. 

Finally, good luck with the wiring!