Inside the 4 Inch Intake Filter Box
This is a steel box holding a replaceable mat, plumbed into the 4 in intake. Air entering the room is filtered before it reaches anything. The mat is ISO Coarse 45%, or MERV 5. The housing is galvanized sheet steel at 8.1 x 8.1 x 7.8 in and 4 lbs.
Servicing the MERV 5 Intake Filter
A toggle-type fastener opens the box, so a mat change needs no tools. Ruck suggests replacing every three to six months, and in a dusty room it will be the shorter end of that, with the used media recyclable rather than binned. What the box gives you is intake filtering rather than odour control, so a carbon filter still belongs on the exhaust. Budget for a small pressure drop as well, which grows as the mat loads. Fit it before the intake reaches any fan, so nothing abrasive gets to the impeller.
Key Features
- ISO Coarse 45% / MERV 5 Mat: Coarse on purpose, so it traps debris without strangling the intake.
- Galvanized Steel Housing: Holds its shape and resists corrosion in a damp intake path.
- Toggle Fastener: Opens without tools, so mat changes take about a minute.
- 3 to 6 Month Mat Life: A realistic interval, shorter in a dusty or high-pollen space.
- Recyclable Mat: The media can be recycled rather than binned.
- 4 in Duct Fit: Sized for Ruck 4 in components and standard 4 in duct.
Technical Specifications
| Specification | Value |
|---|---|
| Duct Size | 4 in |
| Filter Class | ISO Coarse 45% (G3) / MERV 5 |
| Housing | Galvanized sheet steel |
| Fastener | Toggle type |
| Dimensions (L x H x W) | 8.1 x 8.1 x 7.8 in |
| Weight | 4 lbs |
| Filter Replacement | Every 3 to 6 months |