How do I connect a flanged boot to rectangular duct?
When trying to save money on HVAC repairs by adding new air return lines yourself, the main challenge is figuring out how to connect a factory-flanged boot to a rectangular run of duct using drives and cleats. Even when you have a plan for register placement, the rectangular end's factory flange creates confusion on how to properly join it to the main line.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1figuring out duct sizing and routing independently through online advice
- 2hiring a professional technician
- 3Fold out an inch or so to screw it to the duct
- 4Cut some of the boot off to fit clearance issues
- 5Fold the cut edges flat or at a 90-degree upward angle so the boot sits around the flanges
- 6Use a round tap off into pipe instead and put the boot at the end delivering air
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“How the heck do I connect this flanged boot to rectangular duct? I have drives and cleats but the flange is throwing me off.”source ↗
“Long Story Short, I need new HVAC unit and need to save money wherever I can.”source ↗
“I was advised to add at least 400 cfm to my air return in two separate locations (it is struggling to keep up with the house).”source ↗
“I have a plan for where to place the registers and how to get to them, but wanted some advice on how to supply two new lines off my main return”source ↗
“I’m good for round to round. But confused about how to connect flange on boot to rectangular run of duct.”source ↗
“Yes. I’m set on connecting round to round. I am confused as to how to connect the rectangular end of this boot (particularly the factory flange) to the rectangular long stretch of duct.”source ↗
Where this came up
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