Quick answer

Buy the louver kit that matches your existing exhaust fan model, not just the shutter size. Choose the 18 in. kit for IF18 or IF18UPS fans and the 36 in. kit for IF36 fans.

Why shutter size alone is not enough

A shutter that measures 18 or 36 inches across tells you the opening size, but it does not confirm which louver vanes and stabilizers will seat correctly in your frame. The louver kit is built for a specific fan family, so the model number is the reliable starting point.

If you order by size only, you may receive vanes that are close but not correct for your frame. Checking the model plate first avoids a return and a second wait for parts.

When to replace the whole louver set instead of one vane

Both kits include multiple vanes, stabilizers, and hardware, so you can replace one damaged louver or refresh the full set. If several vanes are bent, misaligned, or no longer close evenly, replacing the full set is usually the cleaner fix.

If only one vane is visibly damaged and the rest move freely, a single-vane swap can be enough. The kit still gives you matching spares for later.

Decision rules for choosing a louver kit

  • Start with the fan model: Read the model plate on your exhaust fan. If it says IF18 or IF18UPS, choose the 18 in. louver kit. If it says IF36, choose the 36 in. louver kit. A model match beats a tape-measure match every time.
  • Confirm the shutter size: Use the shutter size only as a cross-check after you have the model number. The 18 in. kit is for 18 in. exhaust fans and the 36 in. kit is for 36 in. exhaust fans.
  • Decide between partial and full replacement: If one or two vanes are damaged, either kit can supply replacements. If most vanes are bent or the shutter no longer closes evenly, plan to replace the full set with the matching kit. Count damaged vanes before ordering so you know whether one kit covers the job.
  • Check what is already on the frame: Both kits include stabilizers and hardware, so you do not need to source those separately. Reuse existing fasteners only if they are in good condition and match the kit hardware.

Product facts

  • Louver Kit for 18 In. Exhaust Fan Shutter: Includes 5 lightweight aluminum louver vanes with shutter stabilizers and necessary hardware. This gives you enough vanes to replace a partial set on an 18 in. shutter without ordering individual pieces.

    Louver Kit for 18 In. Exhaust Fan Shutter

    Louver Kit for 18 In. Exhaust Fan Shutter

  • Louver Kit for 36 In. Exhaust Fan Shutter: Includes 10 lightweight aluminum louver vanes with shutter stabilizers and necessary hardware. The larger vane count suits a full 36 in. shutter refresh and keeps spare vanes on hand for future damage.

    Louver Kit for 36 In. Exhaust Fan Shutter

    Louver Kit for 36 In. Exhaust Fan Shutter

Who should choose which kit

Best for

  • Owners of IF18 or IF18UPS exhaust fans who need to replace damaged or misaligned shutter louvers
  • Owners of IF36 exhaust fans who want a full set of 10 replacement vanes with stabilizers and hardware

Not for

  • Fans from other model families, even if the shutter measures 18 or 36 inches
  • Shutters that need a different part entirely, such as a motor or blade kit