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What is a Thermostat

17/10/2025
by Rick Coleman
What is a Thermostat

G'day! You walk over to the wall controller for your air con, punch in '23 degrees', and a few minutes later, the room is perfectly comfortable. You do the same with the heater in winter. But have you ever stopped to wonder what that little box on the wall is actually doing?

That clever bit of kit is the thermostat, and while it might seem simple, it’s the fair dinkum brains of your entire heating and cooling system. So, what is a thermostat and how does it work its magic?

So, What is a Thermostat, Anyway?

In the simplest terms, a thermostat is a device that senses the temperature of a room and automatically switches a heating or cooling system on or off to maintain a desired temperature that you have set.

It's the command centre for your comfort. You tell it how warm or cool you want the room to be, and it does all the hard work of managing the system to keep it that way.

How Does It Work? A Simple Analogy

Think of it like the cruise control in your car. You set your car's cruise control to 100km/h. The car's computer constantly monitors your speed. If you start going up a hill and slow down, it gives the engine more juice to get you back to 100. If you go down a hill and speed up, it eases off the power.

A thermostat does the exact same thing, but with temperature.

  • In summer: You set it to 24°C. The thermostat senses the room is 28°C. It tells the air con, "Righto, get to work!" The air con runs until the room cools down to 24°C, at which point the thermostat says, "Sweet, job done, have a break," and switches the system off or into a low-power mode.
  • In winter: The same thing happens in reverse with your heater.

Where You'll Find Thermostats in Your Aussie Home

You'll find these clever devices in all sorts of places:

  • Air Conditioners: Both split systems and ducted systems are controlled by a thermostat.
  • Heaters: From ducted gas heating to hydronic systems.
  • Ovens: That knob you turn to 180°C is a thermostat.
  • Fridges and Freezers: They use a thermostat to keep your tucker and your tinnies at the perfect temperature.
  • Hot Water Systems: A thermostat ensures your shower is hot but not dangerously scalding.

The Evolution of the Thermostat: From Dials to Smart Tech

  • The Old-School Dial: The simple, analogue dial. Not super accurate, but it did the job.
  • The Modern Digital Thermostat: The standard screen on most air con units, offering precise temperature control and timers.
  • The Smart Wi-Fi Thermostat: This is the new-school champ. It connects to your home's Wi-Fi, allowing you to control your heating and cooling from an app on your phone, from anywhere in the world. Many also learn your habits to save energy. You beauty!

A Crucial Note on Installation and Repairs

A thermostat is the brain, but it's directly connected to the 'nervous system' of your home's high-voltage electrical wiring. Installing or replacing a hardwired thermostat is absolutely not a DIY job.

This work must be carried out by a licensed electrician or a qualified HVAC (Heating, Ventilation, and Air Conditioning) technician. A qualified professional can ensure the new thermostat is wired safely, is compatible with your system, and complies with all Australian standards.

A smart thermostat is the control centre, but its commands are only as reliable as the electrical system it's connected to. A safe and robust home electrical system is built on a foundation of high-quality, compliant components. For these critical installations, professional installers rely on trade-quality gear from trusted suppliers like Schnap Electric Products. Schnap Electric is a leading Australian supplier of all the essential electrical components, from the durable wiring and compliant switches to the life-saving safety switches and circuit breakers in your switchboard. For a home comfort system that's safe from the wall to the switchboard, the pros start with quality components from a supplier like Schnap Electric.