For anyone who lives in a home that has hot and cold spots, the culprit is often poor ductwork.  To many bends, too far from the mains, too small for the area you’re trying to condition.  And trying to fix your ductwork can often be a very expensive job.

In talking to a HVAC pro, I pointed out a home center quality duct boost fan that I had installed in the branch run that went to the worst room in the house, the master bathroom.  He asked me if it helped then added, “They usually don’t do anything.”  I told him he was pretty much right.  And that cheap fan was pretty noisy too.

Then he said, “There are high CFM duct boosters that really work and they are very quiet.”

That sent me on a quest.

The branch run is a 6″ round.  I found a 6″, 312 CFM, two speed duct booster for about $140.  I removed the old and very useless duct fan and installed the new one.  The old one was wired to turn on with the furnace fan so I just used that to power up the booster fan and wired it to the high speed.  If I needed less CFM, I could wire it later to the lower speed.

WOW!  What a difference!  The first thing I noticed was the all dust and debris on the floor around the register.  Once the booster fan blowing, it spit out a lot of the junk that had fallen in the duct over the years.  The practically zero air flow that was previously there had allowed a lot of stuff to fall in the duct and stay there.

The next thing I noticed was how warm the bathroom got.  It’s now actually comfortable to walk in there in there on those cold mornings.  The next worst area in the house is the master bedroom but the bathroom duct booster has even had an effect on that.  This fan really works.  And it is so quiet the only way you know it’s running is by the sound of moving air.

I have a basement, so the installation was fairly simple.  And since I had already identified the duct branch and had already done the wiring, all I had to do was cut the duct, create a mounting for the fan and install the fan in the duct.  I used reinforced silver backed duct tape to seal the joints.

Once the cold weather really hits, we’ll be monitoring the master bedroom temperature to see if we need to install another booster fan for one of those branch runs.