Mk1 SMSCom 7-Amp Twin Fan Speed Temp Controller - Independent Intake and Extract Fan Control
Best for: Growers running separate intake and extraction fans who want both automatically balanced against a single temperature target.
Our thoughts
This is the original SMSCom Twin, the analogue, dial-controlled unit that's been a mainstay in UK grow rooms for years before the more compact Mk2 came along. It's a bigger unit and a simpler control layout than the Mk2, but the twin-fan negative-pressure control it does is exactly the same job, done reliably. Does exactly what it should, day in, day out.
The Mk1 SMSCom 7-Amp Twin Fan Speed Temp Controller manages an intake fan and an extraction fan independently from a single external temperature sensor, fitted on a 2.9 metre lead so it can sit in the canopy rather than by the controller itself. It uses pulse width modulation to vary both fan speeds and automatically adjusts them to hold your set temperature while maintaining negative pressure in the tent or room, which keeps smells and light leaks from escaping through gaps.
Control is via three physical knobs, one for minimum fan speed, one for target temperature, and one for maximum fan speed, so you set the operating range and the controller works within it rather than needing any digital setup. Each of the two outputs handles up to 800 Watts (around 3.5 Amps), giving a combined rated capacity of 7 Amps across both fans.
How it compares
SMSCom's own range has since added a more compact model, and other brands offer similar twin-fan control at different price points.
- Versus the newer SMSCom Mk2 Twin, which is roughly half the size and uses digital "Motion Flow" software with a learning algorithm, the Mk1 uses simple analogue knob control and a larger case, but does the same core intake/extract balancing job.
- Versus Ecotechnics' Evolution Digital Fan Speed Controller, which also handles heater and CO2 integration, the SMSCom Twin is a more focused, fan-only unit at a lower price point.
- Versus Autopilot's multi-function environmental controllers, which bundle temperature, humidity and CO2 control into one unit, the SMSCom Twin sticks to fan speed and temperature only, which keeps it simpler to set up.
You're getting proven, if old-school, twin-fan control rather than the newest digital interface, at a price point below full multi-function controllers.
Usage guidance
Setup is entirely manual via the three knobs, no app or digital menu to navigate.
Sensor placement
Mount the temperature sensor at canopy height on its 2.9 metre lead, not next to the controller itself, so it reads the temperature your plants actually experience.
Setting the range
Set the minimum speed knob high enough to maintain basic air exchange even when the room is cool, then set your target temperature and maximum speed to cover the hottest point in your light cycle.
Balancing intake and extract
Because both fans are controlled independently, check that intake speed is slightly lower than extraction to hold negative pressure and stop smells escaping through gaps.
Technical specifications
- Fan outputs: 2 independent channels (intake and extract)
- Rated load per output: Up to 800W (approx. 3.5A)
- Combined rated capacity: 7 Amps
- Control type: Analogue, three-knob (min speed / temperature / max speed)
- Speed control method: Pulse width modulation
- Temperature sensor lead: 2.9 metres
- Function: Maintains set temperature and negative pressure via independent fan speed control
Who this is for
- Growers running separate intake and extraction fans who want them automatically balanced
- Anyone who prefers simple knob control over a digital menu system
- Growers who need reliable negative pressure to stop odour and light leaks
- Growers who don't need CO2 or humidity control bundled into the same unit
If you want a smaller footprint or digital control, the SMSCom Mk2 Twin is the newer alternative in the same range.
Our take
It's the original, larger-bodied version of a controller that's proven itself in UK grow rooms for years, doing intake/extract balancing with straightforward analogue controls rather than a screen and menu system.
Worth picking up if you want reliable twin-fan control without paying for digital features you might not use.
