Affiliate disclosure: We are enrolled in the Amazon Associates Program, and this means we may earn a modest commission if you buy through our referral links—at no extra cost to you.
| Location | Hole Size | Critical Mistake to Avoid |
|---|---|---|
| Sheet metal duct | 1.5″ | Forgetting to deburr edges (causes air leaks) |
| Air handler box | 1.25″ | Cutting near refrigerant lines (causes leaks) |
