Climate & Ventilation — Ø 125 mm

For 100x100 and 120x120

Ø 125 mm is the usual size for a 100x100 and an economically built 120x120, and it is by some distance the deepest size in this category. Both fans and carbon filters offer their widest choice here. That is welcome and it makes choosing harder, so it helps to work in a fixed order.

Choose the filter first, then the fan

That sounds backwards and it is not. The filter sets how much resistance your fan has to overcome, so only once you know which filter you are hanging do you know which fan delivers enough. In this size that choice is wide: Prima Klima with the Eco Line and the heavier Industry version, Can-Filters with the smaller Can-Lite sizes, the Inline that may sit anywhere in the duct, and the plastic CAN Original, plus a Rhino.

Fans: the widest choice in the shop

From Vents there is the VK as a centrifugal in several versions, the VKO as an axial, the TT and TT Pro as mixed-flows and the Quietline built around silence. From Can-Fan the RK 125 L at 350 cubic metres per hour and the RK 125 LS at 370. Alongside them G-Tools with two speeds or a temperature controller, Prima Klima with the temperature-controlled PK125EC-TC, and Garden Highpro for a straightforward build.

Or fan and filter together

Because this size is so common, complete combinations are supplied on it. The G-Tools kits pair a GT fan with a Prima Klima filter, with or without a controller, and one version includes a silencer. Prima Klima supplies the PK 125 EC-TC with a matching filter. That saves working out whether the connection sizes line up.

Three ways to get it quiet here

Ø125 has both a 45 cm Can-Fan silencer and the G-Tools silencer that fits the GT fans, and acoustic Sonoconnect comes in this size too. It is also the smallest diameter the Airfan Odor connect is supplied in.

Frequently asked questions

Should I put a 150 filter on a 125 fan?
No. There are plenty of filters in Ø125, so you need no reducer. Every reducer costs pressure, so keep the whole chain on one size.

Is Ø125 enough for a 120x120?
For an economically built one, yes. If the room runs warm or carries a lot of light, Ø150 gives you more headroom, especially with a filter and a silencer.

Why are there so many versions of the same size?
Because this is the most common diameter and manufacturers supply their whole programme on it. Compare on the stated airflow and on how you want to control it, not on the model name.