---
product_id: 82236934
title: "NF-A4x20 PWM"
brand: "noctua"
price: "292 kr"
currency: DKK
in_stock: null
reviews_count: 13
category: "Noctua"
url: https://www.desertcart.dk/products/82236934-nf-a4x20-pwm
store_origin: DK
region: Denmark
---

# >150,000 h MTTF reliability 5000 RPM max speed Ultra-quiet 14.9 dB(A) NF-A4x20 PWM

**Brand:** noctua
**Price:** 292 kr
**Availability:** ❌ Out of Stock

## Summary

> 🛠️ Tiny fan, huge upgrade — silence your gear, elevate your space!

## Quick Answers

- **What is this?** NF-A4x20 PWM by noctua
- **How much does it cost?** 292 kr with free shipping
- **Is it available?** Currently out of stock
- **Where can I buy it?** [www.desertcart.dk](https://www.desertcart.dk/products/82236934-nf-a4x20-pwm)

## Best For

- noctua enthusiasts

## Why This Product

- Trusted noctua brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Built to Last:** Premium fibre-glass reinforced PBT construction and >150,000 hours MTTF for long-term reliability.
- • **Compact Yet Mighty:** Ultra-compact 40x40x20 mm size fits tight spaces like 1U servers and network gear without compromise.
- • **Whisper-Quiet Power:** Experience near-silent cooling at just 14.9 dB(A), perfect for noise-sensitive workspaces.
- • **Precision PWM Control:** Automatic speed adjustment via 4-pin PWM ensures optimal airflow and energy efficiency.
- • **All-Inclusive Installation Kit:** Comes with anti-vibration mounts, extension cables, and OmniJoin adaptors for seamless integration.

## Overview

The Noctua NF-A4x20 PWM is a premium 40x40x20 mm quiet fan designed for compact devices like 1U servers, routers, and NAS units. Operating at up to 5000 RPM with ultra-low noise levels of 14.9 dB(A), it features advanced acoustic optimization and PWM speed control for efficient, whisper-quiet cooling. Built with durable fibre-glass reinforced PBT and boasting a >150,000 hour MTTF, it includes a comprehensive mounting and connection kit to ensure easy installation and long-lasting performance.

## Description

Buy Noctua NF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown): Case Fans - desertcart.com ✓ FREE DELIVERY possible on eligible purchases

Review: Noctua NF-A4x20 PWM: The Tiny Fan That Turns Screaming Network Gear Into a Polite Roommate - The Noctua NF-A4x20 PWM is one of those tiny components that punches hilariously above its weight. At 40mm, it looks like it should be decorative, yet it’s capable of transforming loud, grumpy network gear into something that no longer sounds like it’s preparing for takeoff. Drop one of these into a firewall or switch that shipped with a fan clearly designed by someone who hates silence, and suddenly the room feels calmer, cooler, and more civilized. It’s small, precise engineering doing a big favor for your ears. In real-world use, this fan is a peace offering to anyone who’s had to live near enterprise hardware. It moves air efficiently for its size, ramps smoothly under PWM control, and avoids that high-pitched whine that cheaper 40mm fans love to produce. Thermals stay under control, airflow is steady, and the fan itself behaves like it understands its job description. It doesn’t try to impress; it just quietly fixes a problem you’ve been ignoring because you assumed loud was unavoidable. Where the NF-A4x20 really shines is in reclaiming sanity from gear that was never designed for human proximity. Firewalls, routers, compact servers—anything that technically fits under a desk but audibly objects to the arrangement—benefits immediately. It’s the kind of upgrade that makes you wonder why manufacturers insist on shipping jet-engine fans in devices meant to live in offices. The improvement isn’t subtle; it’s the difference between “background noise” and “oh, I forgot that thing was on.” Noctua’s usual attention to detail is all here: solid bearings, predictable PWM behavior, and build quality that inspires confidence. It’s not flashy, it’s not exciting, and it doesn’t need to be. It simply does what good engineering is supposed to do—solve a problem cleanly, quietly, and without introducing new ones. Pros • Dramatically quieter than stock 40mm fans • Smooth, predictable PWM control • Excellent airflow for its size • High-quality bearings and long service life • Instantly improves livability of noisy network gear Cons • 40mm size still limits absolute airflow • Requires compatible PWM control • Physical fit can vary by device • Once installed, you’ll notice how bad the original fan really was
Review: Fantastic quiet fan - I thought this was really over priced for a switch fan replacement, but the quality and all the extra mounting hardware and cable connections really made my install so much easier. The fan runs quiet and also includes a resistor cable if you want to slow the fan and quiet things down even more. I will buy another for a dvr with the same size fan that has a failing fan bearing.

## Features

- Premium quiet fan, 40x40x20 mm, 12V, 4-pin PWM, max. 5000 RPM, max. 14.9 dB(A), >150,000 h MTTF
- Award-winning A-series design with Flow Acceleration Channels and Advanced Acoustic Optimisation frame for superior quiet cooling performance
- 40x20mm size ideal for 1U servers or replacing fans in network and storage equipment (routers, switches, NAS etc.) or other devices such as DVRs
- 4-pin PWM version for automatic speed control via 4-pin PWM fan headers, 5000rpm maximum speed (4400rpm with supplied Low-Noise Adaptor)
- Includes anti-vibration mounts, fan screws, extension cable, y-cable and OmniJoin adaptor set for connecting the fan to proprietary fan headers

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B071W93333 |
| Air Flow Capacity | 9.4 Cubic Meters Per Hour |
| Best Sellers Rank | #31 in Computer Case Fans |
| Brand | Noctua |
| Compatible Devices | Desktop |
| Cooling Method | Air |
| Date First Available | July 12, 2017 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 5.6 ounces |
| Item model number | NF-A4x20 PWM |
| Manufacturer | Noctua |
| Material | Fibre-glass reinforced PBT |
| Maximum Rotational Speed | 5000 RPM |
| Noise Level | 14.9 Decibels |
| Number of Items | 1 |
| Power Connector Type | 4-Pin |
| Product Dimensions | 1.57"L x 1.57"W x 0.79"H |
| UPC | 841500110109 |
| Voltage | 12 Volts |

## Product Details

- **Air Flow Capacity:** 9.4 Cubic Meters Per Hour
- **Brand:** Noctua
- **Compatible Devices:** Desktop
- **Cooling Method:** Air
- **Material:** Fibre-glass reinforced PBT
- **Maximum Rotational Speed:** 5000 RPM
- **Noise Level:** 14.9 Decibels
- **Power Connector Type:** 4-Pin
- **Product Dimensions:** 1.57"L x 1.57"W x 0.79"H
- **Voltage:** 12 Volts

## Images

![NF-A4x20 PWM - Image 1](https://m.media-amazon.com/images/I/71lyRpVR4OL.jpg)
![NF-A4x20 PWM - Image 2](https://m.media-amazon.com/images/I/81abh0+LmWL.jpg)
![NF-A4x20 PWM - Image 3](https://m.media-amazon.com/images/I/71ZYfijIyBL.jpg)
![NF-A4x20 PWM - Image 4](https://m.media-amazon.com/images/I/71dP+BWXMRL.jpg)
![NF-A4x20 PWM - Image 5](https://m.media-amazon.com/images/I/61xqdXxj1uL.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: What is the CFM rating of this fan?**
A: 5.5 cfm

**Q: would anyone recommend this fan for a 3d printer hontend/part cooling fan?**
A: Yes, we'd recommend using this fan for your 3d printer. (Please note that this is a 12V DC fan.)

**Q: What is de difference between noctua nf-a4x20 pwm and noctua nf-a4x20 flx?**
A: one fan is pwm controllable (pwm), the other is not (flx).

PWM controlling: https://en.wikipedia.org/wiki/Computer_fan_control

**Q: Is a 4-pin two Fan splitter included?**
A: yes

## Customer Reviews

### ⭐⭐⭐⭐⭐ Noctua NF-A4x20 PWM: The Tiny Fan That Turns Screaming Network Gear Into a Polite Roommate
*by D***Q on December 26, 2025*

The Noctua NF-A4x20 PWM is one of those tiny components that punches hilariously above its weight. At 40mm, it looks like it should be decorative, yet it’s capable of transforming loud, grumpy network gear into something that no longer sounds like it’s preparing for takeoff. Drop one of these into a firewall or switch that shipped with a fan clearly designed by someone who hates silence, and suddenly the room feels calmer, cooler, and more civilized. It’s small, precise engineering doing a big favor for your ears. In real-world use, this fan is a peace offering to anyone who’s had to live near enterprise hardware. It moves air efficiently for its size, ramps smoothly under PWM control, and avoids that high-pitched whine that cheaper 40mm fans love to produce. Thermals stay under control, airflow is steady, and the fan itself behaves like it understands its job description. It doesn’t try to impress; it just quietly fixes a problem you’ve been ignoring because you assumed loud was unavoidable. Where the NF-A4x20 really shines is in reclaiming sanity from gear that was never designed for human proximity. Firewalls, routers, compact servers—anything that technically fits under a desk but audibly objects to the arrangement—benefits immediately. It’s the kind of upgrade that makes you wonder why manufacturers insist on shipping jet-engine fans in devices meant to live in offices. The improvement isn’t subtle; it’s the difference between “background noise” and “oh, I forgot that thing was on.” Noctua’s usual attention to detail is all here: solid bearings, predictable PWM behavior, and build quality that inspires confidence. It’s not flashy, it’s not exciting, and it doesn’t need to be. It simply does what good engineering is supposed to do—solve a problem cleanly, quietly, and without introducing new ones. Pros • Dramatically quieter than stock 40mm fans • Smooth, predictable PWM control • Excellent airflow for its size • High-quality bearings and long service life • Instantly improves livability of noisy network gear Cons • 40mm size still limits absolute airflow • Requires compatible PWM control • Physical fit can vary by device • Once installed, you’ll notice how bad the original fan really was

### ⭐⭐⭐⭐⭐ Fantastic quiet fan
*by J***S on February 14, 2026*

I thought this was really over priced for a switch fan replacement, but the quality and all the extra mounting hardware and cable connections really made my install so much easier. The fan runs quiet and also includes a resistor cable if you want to slow the fan and quiet things down even more. I will buy another for a dvr with the same size fan that has a failing fan bearing.

### ⭐⭐⭐⭐⭐ Perfect replacement for Unifi USW Enterprise 24 POE stock fans!
*by T***N on February 27, 2026*

Move a lot of air. Even at highest RPM, they are still whisper quiet. I used these to replace the loud stock fans in my Unifi USW Enterprise 24 POE switch. I had to remove the plastic alignment tab on the fan header but other than that, they worked perfectly.

## Frequently Bought Together

- Noctua NF-A4x20 PWM, Premium Quiet Fan, 4-Pin (40x20mm, Brown)
- Noctua NF-A4x10 FLX, Premium Quiet Fan, 3-Pin (40x10mm, Brown)
- Noctua NF-A8 PWM, Premium Quiet Fan, 4-Pin (80mm, Brown)

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---

*Product available on Desertcart Denmark*
*Store origin: DK*
*Last updated: 2026-03-06*