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Temperature controlled fans usable for DIGITUS Professional Network Wall Housing – Soho Wall Cabinet: Amazon.de: Computer & Accessories

Posted by jpluimers on 2025/12/26

TL;DR: avoid Digitus AC fans, but use DC case fans with built-in/external temperature controller plus 12V or USB-step-up power supply and optionally fan grilles/meshes.

A while ago, I bought a 7U shallow 19-inch rack cabinet to house some of our network equipment for the offices and other rooms at the top floor: [Wayback/Archive] DIGITUS Professional Network Wall Housing – Soho Wall Cabinet: Amazon.de: Computer & Accessories

Since it was to be mounted in the boiler room, which is on the top floor under a flat roof, it would get warm so I wanted fans installed in it under or over the air vents in the housing (the cabinet is delivered as flat-pack with parts pictured below and requires about half an hour assembly time):

The holes seemed to match 120mm fans, but I first went to look at these digitus products

  1. [Wayback/Archive] Digitus Roof Vent for 48.3 cm 19 Inch Cabinets with Thermostat 2 Vents Air Circulation per Minute 6.4 square metres: Amazon.de: Computer & Accessories

    Product dimensions 40L x 43.8W x 4H centimetres
  2. [Wayback/Archive] DIGITUS Roof Fan Unit for NW Cabinet (Dynamic / Unique) & SRV Cabinet (Dynamic) – 2x Fans – Thermostat – Grey : Amazon.de: Computer & Accessories

    Width. 430mm ; Height. 45mm ; Depth. 415mm

  3. [Wayback/Archive] Digitus DN-19 FAN-2-HO 2 Rack Fan Kit Grey : Amazon.de: Computer & Accessories

    Product dimensions 45L x 400W x 438H millimetres

The first didn’t have a look at the internals, but from the externals I already feared these were AC-fans, and know that DC-fans (especially when speed-controlled for instance with a temperature controller) are way more efficient ¹.

Luckily the second product had pictures of the internals: the fans are DEMEX AXIAL FAN AC230V.

 

[Wayback/Archive] 61VsD07TZzL._AC_SL1500_.jpg (1500×829)

The [Wayback/Archive] Fans – Demex come in these sizes:

running at these voltages and power usages:

 
Power usage for each model
Voltage 80 x 80 x 25 92 x 92 x 25 120 x 120 x 25 120 x 120 x 38 172 x 150 x 50
24VDC N/A N/A N/A 6.24W N/A
110/115VAC 10/11W 12/13W 18/17W 20/19W 34W
220/230VAC 10/11W 12/13W 18/17W 20/19W 34W

Note the DC fan is using 33% of the power that the equivalent AC fan uses!

Given the height unit being close to 1U which is 1¾ inches (~44.45 mm) my estimate was the fans being the 120 x 120 x 25 model.

So I was not surprised for the 2 FAN devices to use 50 Watts of power, nor the second review:

  1. [Wayback/Archive] Stromverbrauch absolut inakzeptabel im Privatbereich!

    Umgebung:

    19“ Digitalus Serverschrank im Einfamilienhaus mit Unifi Router, NVR und Switches sowie Heimserver und APC Batteriepack. Soll im HWR Frischluft durch diesen Lüfter bekommen.

    Grundsätzlich ist dieses Lüfterpaket GENAU DAS was ich gesucht habe. Also zwei Schrauben, Stecker rein, glücklich sein… Wenn da nicht der Stromverbrauch wäre. Gerade zuhause müssen für mich Dauerläufer sparsam sein. Im HWR wird es durch verschiedene Geräte und die Heizung gerne mal warm. Da muss der Serverschrank Frischluft haben. Aber nicht mit knapp 50 Watt! Das ist mehr als der Heimserver und der Router zusammen!
    Also ging der Lüfter leider zurück :( Im gewerblichen Bereich mag das egal sein. Aber zuhause nicht.

    Zwei 120er Arctic Lüfter an einem alten 12V Netzstecker verrichten jetzt die gleiche Arbeit für 4 Watt. Im Vergleich zu den knapp 50 Watt nur ein kleiner Bruchteil an Stromaufnahme UND Geräuschkulisse. Ganz zu schweigen vom Preis… 100€ gespart

  2. [Wayback/Archive] Mieserable Qualität

    Juni 2020: Diese Lüftereinheint ist groß und nimmt im 19′ Schrank unnötig viel Platz weg.
    Die Innenkonstruktion ist simpel gehalten: es gibt kein Netzzeil, nur einen Schalter, eine Sicherung und den Thermoschalter. Die 120x120x40mm No-Name-Lüfter werden direkt an 230V betrieben.
    Die Lüfter sind schon mäßig laut.

    Der Thermoschalter ist komplett unbrauchbar. Man sollte ihn zwischen 0-60C einstellen können. Tatsächlich schaltet er aber nur dann, wenn man ihn auf 0-10 Grad Celsius stellt, bei einer Test-Umgebungstemperatur von 30 Grad.

    Der einzige Grund warum man dieses Lüftermodul kauft ist weil es genau in die Deckeneinheit vom DIGITUS Außenschrank passt.
    Wer versucht ihn umzurüsten, auf höherwertige 120x120mm Lüfter sollte bedenken, dass man dann auch ein 12V Netzteil selbst nachrüsten müsste, und die Thermosteuerung kann auch nicht sinnvoll verwendet werden.

    Ich gebe diesem Frankenstein-Produkt gerade noch 2 Sterne.

DC Alternatives

Basically you can go two routes from here:

  1. A DC temperature controller with standard fans
  2. DC fans with built-in temperature controller like[Wayback/Archive] ARCTIC F12 TC – Temperature Controlled 120 mm Case Fan, Standard Case Fan, Temperature Sensor Regulated RPM, Push or Pull Configuration, 300-1350 rpm – Black: Amazon.de: Computer & Accessories

Most DC fans run at 12V, so you also need a 12V power source, probably via a USB adapter (usually readily available). A fan grille or mesh might also come in useful. Some (combinations) products you could consider:

¹ yes, DC fans are way more efficient than AC fans

Apart from the above note “Note the DC fan is using 33% of the power that the equivalent AC fan uses!“, check out these links (there are way more):

  • [Wayback/Archive] DC Ceiling Fans vs AC – Which Ceiling Fan Is Best?

    AC vs DC:

    The advantages of a DC motor ceiling fan over an AC motor ceiling fan:
    • In most cases, they use less energy – up to 70% less than a standard AC fan.
    • They are generally extremely quiet.
    • They will often have more speed options, the reverse function on the remote, and are generally faster to start, stop and change speed.
    • The motor is generally more compact and lighter, which allows for a slimmer motor design.

    …

    The advantages of an AC motor ceiling fan over a DC motor ceiling fan:
    • DC ceiling fans tend to be more expensive when compared to an equivalent AC model. Although you do use less electricity and therefore save money there, it is minimal. For example, if a DC fan saves you 20W per hour of use, and you use it for 10 hrs per day, 100 days per year (all night, all of the summer, on low speed), you save about $3.50 per year (off peak rates).
    • AC fans can be controlled from a wall control, pull cord or remote, while DC fans can generally only be controlled by remote (very few exceptions – see below*). Remotes are more likely to be lost, broken, run out of batteries. Some DC fans are available with an optional wall controller, at an extra charge.
    • AC fans are still extremely energy efficient, a standard model will use no more than 100watts on high speed.
  • [Wayback/Archive] Why don’t we use DC ceiling fans instead of AC ceiling fans if they’re considered to be more efficient ? : AskEngineers
    If you have an AC motor directly powered by the AC voltage coming in, you have no control over the frequency, because your incoming voltage is always 60 Hz (in the US, some places like Europe it’s 50 Hz). The advantage of a DC Brushless is that the controller/inverter lets you generate any frequency you want to drive the motor. So to change speeds on the AC motor you need to drive it in weird ways to get different speeds and it kills the efficiency (it also tends to make a lot of noise, hence why AC motor ceiling fans make that buzzing sound when they are driven outside of their native frequency). The DC Brushless is being driven by whatever frequency you want natively, so the efficiency is much better and it’s much quieter.
    Don’t think of as a difference between AC/DC. Think of it as getting much better control over the motor.

Queries:

--jeroen

Images from Amazon:

This entry was posted on 2025/12/26 at 18:00 and is filed under Hardware, LifeHacker, Network-and-equipment, Power User. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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