My furnace filter sitting diagonally.

Creating a Sheet Metal Bracket to Keep a Furnace Filter In Place 3


So my buddy Greg Ellis hits me up on Skype this morning and asks if I have time to “take a walk”, which is how we like to meet and discuss business. We both like exercise, and it’s a great way to get both the blood and entrepreneurial juices flowing. But today, since it’s the last day of our vacation here in Utah, I’d promised my family they could have Krispy Kreme Donuts for breakfast, so I told Greg we could talk on a donut run instead. He didn’t object, and was at my house a few minutes later. 🙂

After picking up the donuts, we were headed back to my house when I suddenly yelled out “Oh! I need sheet metal!” as I turned sharply into the Lowes Hardware parking lot. Greg laughed and said “Of COURSE you do!” as if it’s something everyone yells when returning home with a dozen Krispy Kremes.

There’s a project here at the Utah house that I keep forgetting to tackle, into which Greg was unwittingly sucked. He’s always a great sport, however, so we still talked biz as we roamed the store to grab a 6 x 18″ piece of galvanized aluminum, some tin snips, and some sheet metal screws.

Back at home, Greg was more than happy to help out as I checked this minor annoyance project off my list. Thanks again for the help, Greg!

This project centers around the filter in my furnace. The HVAC “professional” who installed the furnace in this house gave me enough room in the return duct to insert a 20 x 25 x 1 inch filter, which sits diagonally inside the duct, like this:

My furnace filter sitting diagonally.

My furnace filter sitting diagonally.

However, when the furnace’s fan turns on, the suction will sometimes pull the bottom of the filter towards the fan, which stands the filter straight up on the right side of the intake duct. Then, when the fan shuts off and the suction disappears, the top of the filter will fall backwards, thereby allowing unfiltered air into the furnace. It was sloppy ductwork on the part of the installer, and it’s something I’ve been meaning to fix for years.

Measure Twice, Cut Once, Cut Yourself

Because the duct is 20″ wide (I know that because a 20″ wide filter fits perfectly) I knew the width of my 18″ sheet of metal would be fine. I used my level as a straight edge to score a 3″ section on the sheet metal:

Scoring my sheet metal.

Scoring my sheet metal.

Then I used my tin snips to cut as closely as I could along the score line:

A metal strip, ready to be bent.

A metal strip, ready to be bent.

Of course, I nicked my thumb on the sharp edge of the newly cut metal, but it wouldn’t be a DIY project without a little blood.

Bend and Fit

Next, I used a an exposed 2 x 4 on the wall of the utility room a jig to help me bend the strip in half, meaning it was no longer just a strip… it was a bracket!

Strip + bending = bracket!

Strip + bending = bracket!

I placed the strip inside the duct and slid it up against the base of the filter, so I’d know where to secure it, then drew a line along the edge of the bracket with a Sharpie:

Finding the right location for the new bracket.

Finding the right location for the new bracket.

Secure and Finish

I removed the filter so I’d have a bit more room to work, lined up the bracket with the Sharpie line, then secured it to the bottom of the duct with some sheet metal screws:

New bracket secured.

New bracket secured.

The final step was to replace the filter, and check to make sure the bottom couldn’t slide forward. Success!

No more filter sliding!

No more filter sliding!

So what have we learned?

We’ve learned that donuts can totally help you remember DIY projects, and we now know the answer to the eternal question: “How many BYU Business School graduates does it take to fix a furnace filter duct?”