18 In. vs 24 In. Exhaust Fan Blade Kits: Fit Guide
By We re still here！ | Published: 2026-11-02
Category: Comparisons
Compare 18 in. and 24 in. exhaust fan blade kits by model fit, blade material, and hardware. Learn which kit matches your Maxx Air fan before you order.
Quick answer
Choose the 18 in. kit for Maxx Air IF18 or IF18UPS fans and the 24 in. kit for IF24 or IF24UPS fans. The deciding factor is your fan model, not the blade count, because both kits include four blades and mounting hardware.
The real difference is model fit, not blade count
Both kits ship with four blades, a spider/hub, screws, and locking nuts, so assembly hardware is not what separates them. The 18 in. kit is listed only for Maxx Air IF18 and IF18UPS exhaust fans, while the 24 in. kit is listed only for IF24 and IF24UPS. That means fan blade kit sizing here is a model-matching exercise: measure if you like, but confirm the model plate before ordering.
The other visible difference is blade material. The 18 in. kit uses aluminum blades; the 24 in. kit uses steel blades. The catalog does not state performance differences between the two materials, so treat material as a specification to note rather than a reason to switch sizes.
What the catalog does not tell you
The supplied records do not include blade pitch, bore diameter, or airflow ratings. If your existing fan has been modified or you are matching a kit to a different brand, those missing specifications matter and should be confirmed with the seller before purchase. For the listed Maxx Air models, the model compatibility note is the strongest fit signal available.
Trade-offs to weigh before you buy
- Fit certainty vs. universal use: The 18 in. kit fits only IF18 and IF18UPS; the 24 in. kit fits only IF24 and IF24UPS. Neither kit is listed as a universal replacement, so a correct model match is the priority. Photograph your fan's model plate before ordering so you can confirm the IF number.
- Aluminum vs. steel blades: The 18 in. kit uses aluminum blades and the 24 in. kit uses steel blades. The catalog does not state a performance or durability difference, so choose by model fit first and treat material as a secondary note.
- Complete hardware vs. reuse: Both kits include a spider/hub, screws, and locking nuts, so you do not need to salvage old fasteners. Reusing worn screws or a bent hub is the bigger risk than choosing the wrong blade material. Inspect the old hub and fasteners for damage before assuming only blades need replacing.
Product facts at a glance
- Fan Blade Kit for 24 In. Exhaust Fans: Includes 4 steel blades, a spider/hub, screws, and locking nuts; listed for Maxx Air IF24 and IF24UPS 24 in. exhaust fans. If your fan is an IF24 or IF24UPS, this kit supplies the full blade assembly and fasteners in one order.
Fan Blade Kit for 24 In. Exhaust Fans - Fan Blade Kit for 18 In. Exhaust Fans: Includes 4 aluminum blades, a spider/hub, screws, and locking nuts; listed for Maxx Air IF18 and IF18UPS 18 in. exhaust fans. For IF18 or IF18UPS owners, this is the matching assembly with aluminum blades rather than steel.
Fan Blade Kit for 18 In. Exhaust Fans
Which kit fits your fan?
Best for
- Owners of Maxx Air IF18 or IF18UPS 18 in. exhaust fans who need a complete blade assembly
- Owners of Maxx Air IF24 or IF24UPS 24 in. exhaust fans who want steel blades and included fasteners
Not for
- Fans from other brands or unlisted Maxx Air models, where bore and pitch are unknown
- Anyone replacing only a grille, motor, or louver rather than the blade assembly
