Answering the common question, these attic fan blades are replacement parts designed to restore airflow and reduce attic heat without replacing an entire unit. The top picks below are best for homeowners who want a straightforward swap, contractors replacing worn blades, and DIY enthusiasts aiming for quiet operation and durable metal construction. Each option fits a standard 1/2″ shaft, features a 12″ diameter with 5 blades and a 32-degree pitch (except where noted), and is designed to keep attic exhaust running smoothly.
| Product | Best For | Key Benefit | Notes |
|---|---|---|---|
| Earthtec FB99100 | Replacement for aging attic fans | Quiet operation with durable metal build | Clockwise from hub side |
| SuperDi 9800528 / 14393 compatible | OEM-style replacement | Exact fit with set screws | Solid, low-noise performance |
| Earthtec A65123 | 1050+ rpm fans or older models | Clear size options, 23° pitch | Check size chart to avoid mismatch |
| Duomimile FB99100 | Durable, easy install | Efficient ventilation | 12″ diameter, 32° pitch |
| Showingo / Superbobi variants | Quick replacements | Solid metal, simple installation | Clockwise from hub side |
Earthtec FB99100 Attic Fan Blade — 12″ 5 Blade
Best for replacing an aging attic fan blade without buying a new fan. This 12-inch, 5-blade metal propeller has a 32-degree pitch and fits 1/2″ shafts with a hub-side clockwise viewing direction. The design emphasizes quiet operation and reliable performance. Best for homeowners who want a straightforward swap that preserves existing fan performance.
Who it’s best for: home owners with a standard 1/2″ shaft attic fan needing a quiet, durable replacement. Why selected: it combines a robust metal build with a precise fit, minimizing vibration and downtime. Caution: ensure the hub side orientation is correct to avoid misalignment during installation.
SuperDi FB99100 Replacement Attic Fan Blade
This exactly matches 12″ diameter, 5 blades with a 32-degree pitch, designed for 1/2″ shafts and equipped with set screws for firm installation. It’s tailored for fans that require clockwise blade mounting from the hub side. Best for: replacing a worn blade in a compatible unit with minimal modification. Limitation: compatibility is strongest with models that align with the 9800528/FB99100 family.
FB99100 Attic Fan Blade Propeller — 12″ 32° 5 Blade
Engineered for stability and durability with a 12-inch diameter and 5 blades at a 32-degree pitch. It is specifically designed for 1/2″ shaft motors and uses set screws to secure the blade. Best for: users needing a stable, long-lasting replacement that resists wobble. Caution: verify the motor shaft and bore are compatible with the 1/2″ specification before purchasing.
Duomimile FB99100 12″ Replacement Blade
Durable replacement blade designed for efficient attic ventilation. This 12″ blade has 5 blades and fits 1/2″ shafts with a clockwise hub-side orientation. Best for: homeowners seeking a balance of durability and ease of installation. Limitation: be sure to match the bore and shaft size with your fan model to avoid installation issues.
Suporbobi / Showingo FB99100 Attic Fan Blade
These variants share the same 12″ diameter, 5 blades, 32-degree pitch, and 1/2″ shaft compatibility. They emphasize a sturdy metal construction and straightforward installation. Best for: quick replacements when the model matches the 1/2″ shaft specification. Caution: installation instructions stress turning off power and confirming hub-side clockwise orientation to avoid misalignment.
Buying Guide: What To Consider When Choosing Attic Fan Blades
- Blade diameter and pitch: Most replacement blades for 12″ attic fans use a 32-degree pitch. A higher pitch increases airflow but may produce more noise; a lower pitch can be quieter but move less air. Match your existing blade’s diameter and pitch for best compatibility.
- Shaft size and mounting: The standard is a 1/2″ shaft with set screws. Confirm shaft diameter and whether the blade is designed to be installed clockwise from the hub side to ensure proper operation.
- Material and durability: Metal blades offer rigidity and long-term durability but can be heavier. Ensure the blade material aligns with your climate and fan housing to prevent fatigue or vibration.
- Fit and compatibility: Some blades are OEM-style replacements designed for specific model numbers or brands. If your fan is older or non-standard, verify compatibility with your model or consider the universal options with clear bore sizing.
- Installation ease: Look for blades labeled as “easy installation” with clear set-screw mounting. Always power down the unit before installation and follow hub-side orientation guidance.
- Noise and vibration: The right blade can reduce attic noise and vibration. Metal blades with precise balance and secure mounting typically offer quieter operation if installed correctly.
Frequently Asked Questions
- What size is a typical attic fan blade?
Most common replacements are 12 inches in diameter with a 5-blade configuration and a 32-degree pitch, designed for 1/2″ shafts.
- Do blades need to be balanced after replacement?
Yes, ensure the blade is securely mounted and balanced to minimize vibration and noise.
- Can I use any 12″ blade on my attic fan?
Only if the shaft diameter, bore, and mounting method match your fan model. Verify hub-side direction and set-screw compatibility.
- Is a higher pitch blade louder?
A higher pitch can move more air but may contribute to higher operating noise if the fan isn’t designed to handle it. Balance airflow needs with noise tolerance.
- What should I do before installing a new blade?
Turn off power and air supply, inspect the hub and shaft, and follow the manufacturer’s installation directions to ensure a secure fit.
- Are replacement blades compatible with all attic fans?
Not universally. Check model numbers, bore size, shaft diameter, and mounting pattern against the replacement blade’s specifications.