Noctua NA-FD1 computer cooling accessory — steel ventilation duct kit, 16 spouts, 4 screws, 7 washers, 5 mm spacers, height 5–45 mm

The Noctua NA-FD1 fan duct kit improves the cooling performance of Noctua NH-L9i and NH-L9a series low-profile CPU coolers in Small Form Factor (SFF) systems where a gap of 5 mm to 45 mm exists between the cooler and a perforated top or side panel. The duct bridges that gap so the cooler draws fresh outside air through the perforated panel instead of hot internal case air, which can improve CPU temperatures by up to about 5 °C or more depending on the setup. The kit is modular and composed of EVA foam spacers of varying thickness, allowing height adjustment in 1 mm increments to fit different cases and configurations.

Advantages

The NA-FD1 provides a measurable temperature improvement for NH-L9 series coolers in compact ITX builds by preventing the intake of warm internal air and enabling intake of cooler outside air. It is compatible with all NH-L9i and NH-L9a model variants (but not with NH-L9x65 or NH-L9x65 SE-AM4). Because the duct creates a 5–45 mm breathing space for the cooler fan, it reduces intake-related turbulence noise compared to very low-clearance configurations. The modular EVA spacer design makes the duct reusable and adjustable when moving the cooler between cases or when changing case clearances.

Suitable for

• Small Form Factor (SFF) ITX builds with a 5–45 mm gap between NH-L9 cooler and perforated panel
• Setups using Noctua NH-L9i or NH-L9a series coolers
• Cases with total clearance around 42–82 mm between motherboard/top or side panel and cooler

Key specifications

• Compatibility: Noctua NH-L9i and NH-L9a series (all listed variants); not compatible with NH-L9x65 or NH-L9x65 SE-AM4
• Height range: adjustable from 5 mm to 45 mm in 1 mm increments
• Spacer set: 7 EVA foam spacers (2 × 10 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm)
• Included parts: 16 plastic tubes and supplied bolts for installation
• Material: Ethylene-Vinyl Acetate (EVA) foam

How to use

Measure the clearance between the top or side perforated panel and the top of the NH-L9 cooler. Select and stack the foam spacers to reach the required duct height (5–45 mm). Replace the original fan screws with the supplied bolts, fit the plastic tubes onto the bolts, add the selected foam spacers, then cut the tubes to the appropriate length so the assembled duct bridges the gap and aligns with the perforated panel. Reinstall the fan and verify alignment and secure fit.

Recommendations

Use the NA-FD1 only with supported NH-L9i and NH-L9a variants. For optimal results, ensure the perforated panel provides direct access to outside air and verify spacer stacking to avoid compression that could alter the target height. Adjust spacer configuration if you change cases or orientations.