G.A.S. Day & Night Temperature Controller — Light-Triggered Heater Control for Grow Rooms
Best for: Growers running LED lights who need separate day and night temperature settings without buying a full environmental control system
Our thoughts
This does one job properly: switching your heater on and off based on whether your lights are on or off. If you're growing with LEDs and want to dial in different temperatures for day and night cycles, this is a solid entry-level solution that won't overcharge you for features you don't need.
The G.A.S. Day & Night Temperature Controller is a dual-dial heater thermostat designed to automate temperature management across your lights-on and lights-off cycles. It uses an integrated light sensor in the probe to detect when your lights switch, then automatically adjusts between two temperature set points you've chosen. Simple, effective, and built to work with heaters up to 2KW — which covers most home growing setups. This is the straightforward alternative to buying a multi-function environmental controller when all you need is temperature control.
How it compares
This sits at the budget end of temperature controllers, but doesn't compromise on the essentials.
- Costs a fraction of full-spec environmental control systems
- Does exactly what it advertises — day/night temperature switching, nothing more
- Light-triggered automation means no manual dial-spinning when your lights come on
- Compatible with any heater up to 2KW, so works with kit you probably already own
- No digital display means fewer things to break and easier to read at a glance
If you need cooling or multi-function control, this isn't your device. But for heating automation with day/night logic, you're looking at solid value here.
Usage guidance
The G.A.S. controller works in a straightforward way:
Installation
Mount the controller near your heater. Position the sensor probe in the middle of your room where air is moving freely — this keeps readings accurate and prevents hot spots. A 4-metre cable gives you decent placement flexibility. Run your heater's power cable through the controller outlet.
Setting temperatures
Left dial controls day temperature (lights on). Right dial controls night temperature (lights off). Dial clockwise to increase, anti-clockwise to decrease. The sensor automatically switches between the two as your lights turn on and off.
How it works in practice
When your lights come on, the controller reads the light sensor and switches to your daytime set point. Your heater runs until the room hits that temperature, then cycles on and off to maintain it. When lights go off, the controller automatically switches to your night set point — usually lower to save energy and reflect natural temperature drops.
Why day/night matters
Plants respond differently to temperature based on light availability. Running a warmer day temperature and cooler night temperature isn't just energy-efficient — it helps control plant shape and structure without chemicals. It's called DIF, and it genuinely works.
Important limitation
This controller only adds heat. It cannot cool if the room gets too hot. If temperature control in the summer is a concern, you'll need a separate cooling controller.
Technical specifications
- Max heater power: 2000W (2KW) — do not exceed this or you'll damage the unit
- Temperature probe: Integrated light sensor with 4-metre cable
- Probe placement: Best suited to middle of room with air circulation
- Control method: Two ergonomic dials — one for day, one for night
- Operational feedback: Green LED indicates heater is on; rapid flashing indicates sensor fault
- Sensor replacement: User-replaceable probe (available separately)
- Function: Heating only — cannot cool
- Compatibility: Works with any heater up to 2KW
Who this is for
- LED growers who need to automate the day/night temperature swing their lights create
- New growers looking for their first piece of automation without complexity
- Budget-conscious growers who want temperature control without multi-function controller pricing
- Growers with small to medium rooms where a 2KW heater is sufficient
- Anyone running a single heater who wants to cut energy waste by dropping night temperatures
Not suitable for growers who need cooling, multi-function monitoring, or have heaters over 2KW.
Our take
This is a solid entry-level heater controller that actually understands how LED growing works. The light-triggered day/night switching is proper automation — no guessing, no manual adjustment, just plug it in and let the sensor handle it. Build quality is decent, and it does exactly what a 2KW heater controller should do without overcomplicating things.
If you're running an LED setup and currently nursing your heater dial through the day, this is worth picking up.
