Field ToolDuct Sizing
The Ductulator.
Can’t fit the original duct? Enter your dimensions and space constraint to find the top 5 equivalent sizes that meet or exceed the original CFM.
Even sizes 4″ – 30″Equal or greater CFMTop 5
01EquivalentsP. 01
Equivalent duct size worksheet
Equivalent Sizes
Original · 16″ × 16″ · 1470 CFM
| Size | CFM | Area | Δ Area |
|---|---|---|---|
| 28″ × 10″Best fit | 1550 | 280 | ±24 |
| 24″ × 12″ | 1600 | 288 | ±32 |
| 30″ × 10″ | 1670 | 300 | ±44 |
| 26″ × 12″ | 1750 | 312 | ±56 |
| 28″ × 12″ | 1950 | 336 | ±80 |
Area in sq in · Sizes meet or exceed the original CFM
CFM is equal-friction airflow at about 0.07 in. wg per 100 ft, from the HVAC Direct field duct sizing chart. Sizes over 12″ on both sides, and the top of the 4″ row, are extended by the chart’s own fitted law.