G-Tools Inline Fan 125mm 1-Speed 420m³/h

The G-Tools 125mm inline fan is a Prima Klima unit built around a Swiss MES AC motor - one of the most reliable motor platforms in professional ventilation. At 420m³/h it is correctly sized for growers running a single 600W HPS light who want quiet, efficient extraction without overspending.

Airflow figures only tell part of the story. Most fans lose significant throughput the moment you attach ducting and a carbon filter. The backward-formed impeller in this fan recovers much of that loss, sustaining closer to its rated 420m³/h even under real-world back-pressure. That matters in a sealed grow tent or cabinet where a pressure drop directly affects temperature and odour control.

This fan suits a single-light room running up to 600W HPS, or an equivalent LED footprint. Pair it with a 125mm carbon filter - G-Tools sell a matching PK K2601 filter - and you have a complete extraction circuit. Use 125mm acoustic ducting between the fan and filter to cut noise further. The supplied mounting bracket lets you hang the fan horizontally, vertically, or at any angle the space demands.

The thermal switch is a practical safety detail. Should the motor run hot - possible in a warm loft or during a hot summer - it cuts in before any damage occurs. This is not a temperature controller for the room; it is motor protection only. If you need room temperature management, add a fan speed controller separately.

At 1-speed the fan runs at full output continuously. This suits growers who prefer simplicity and set their environment with a speed controller or timer. If you later want variable speed, check that any speed controller you buy is rated for AC induction motors - not all controllers are compatible with this motor type.

Grower’s Note: With a 125mm fan running at full speed 24 hours a day, your grow space air should turn over every two to three minutes in a typical single-light setup. Monitor inlet size as well as outlet - a choked passive intake starves the fan and raises room temperature. A 150mm passive inlet hole or equivalent area of mesh keeps negative pressure manageable and the airflow balanced.

Priced at £115, with free UK delivery.