A thermostat, as opposed to a thermometer, can change a room’s temperature. This temperature control dial, positioned on the wall or the boiler, is needed. What is a room thermostat? What are the mechanical thermostats? And how do they all work? You will get answers to all these questions in this article.

What Exactly Is A Thermostat?

How do you regulate the temperature in your house? Smartphone apps and the old-fashioned thermometer dial are just a few of the many options available today. Room thermostats come in many shapes and sizes. A thermostat is nothing more than a heating system’s thermostatic controls. The thermostat can be programmed to maintain a specified temperature in your room or boiler. When the temperature drops, a thermostat activates the heating to keep the house warm. To keep you from overheating, the thermostat turns off the heating when the temperature has reached the preset level.

There are a lot of features and settings available within this framework:

  • Wireless and battery-operated thermostats are also available.
  • Others are linked to the boiler by means of wires.
  • Heating can be configured to run at specific periods of the day using programmable thermostats.
  • Thermostats with built-in intelligence get to know you and your schedule.

How Does A Thermostat For A Room Work?

This brings us to our next question: how does a thermostat actually work? When things heat up, they expand, and when they cool down, they contract. Mechanical room thermostats rely on the concept of thermal expansion to turn on and off an electric circuit. Both bimetallic strips and gas-filled bellows are used in the most prevalent models.

  • Bimetallic Strips

The bimetallic strip of a conventional thermostat comprises two pieces of metal bolted together (or bimetal strip). You can use the strip as a bridge in your heating system’s electrical circuit. Assuming that the “bridge is down,” the circuit is powered, and the heater is on. Metals expand differently when heated, resulting in a slightly bowed strip when the temperature rises. An eventual break occurs because of the extreme bending. The power goes off, the heating goes out, and the room begins to cool down as soon as the “bridge” is breached.

What happens next, though? The strip bends back to its original position to return to its original shape as it cools down. The heating is turned back on as soon as it reconnects to the circuit, and the electricity flows again. You can modify the temperature at which the circuit turns on and off by turning the temperature dial. There’s no point (and it would be quite irritating) in the heating turning on and off every few seconds because of the metal strip expanding and contracting. Depending on how well-insulated your home is and how cold it is outside, it could take an hour or more for the mechanical room thermostat to turn back on after it has been switched off.

How are the on and off states of a bimetallic room thermostat set?

  • The thermostat has an exterior dial that allows you to adjust the temperature at which it turns on and off.
  • The dial is linked to a circuit that controls an electrical circuit by bending a bimetal strip that measures temperature.
  • There are two distinct metal strips fastened together: a bit of brass bolted to a piece of iron.
  • The bimetal strip curls inward as the temperature rises because iron expands less than brass when heated.
  • In an electrical circuit, the bimetal strip is used. Electricity can flow through the strip while it’s cool since it’s straight. As a result, the heating system and circuitry are both operational. A heated strip bends and breaks the circuit, preventing any electricity from flowing. The circuit has now been turned off.
  • Gas-filled Bellows

Due to their slow response time to temperature changes, bimetallic strips are a poor choice for temperature sensors. A gas-filled bellows between two metal discs in an alternate thermostat design detects temperature changes more quickly. The discs are springy and flexible because of their high surface area and corrugated (ridged) construction. The gas in the bellows expands as the room warms, separating the discs. A microswitch in the middle of the room thermostat is pushed by the inner disc causing the thermostat to turn off the electric circuit (and the heating). Bellows gas contracts and metal discs reassemble themselves when the room cools. The heating is turned back on after the inner disc travels away from the microswitch. There are a number of additional uses for corrugated bellows thermostats that don’t necessitate the use of gas, such as in older automobiles, where they are filled with volatile (low-boiling) liquids such as diluted alcohol.

  • Wax Thermostats

You can see that all mechanical thermostats (non-electronic ones) use substances that change in size or shape as the temperature rises. Thus, while gas bellows rely on the expansion of gases to work, bimetallic thermostats rely on metals expanding when they heat up. In individual room thermostats, the transition from a gas to a liquid is used to control the temperature. The most common type of wax thermostat is found in automotive engines, radiator valves, and shower mixers. Inside a sealed container, they insert a little piece of wax. A rod is pushed out of the chamber when the wax melts and expands (changes state from solid to liquid) as the temperature increases. This rod is used to turn things on or off (managing the engine cooling system in a car or controlling the mixing of hot and cold water in a shower). In the harsh circumstances of an automobile engine, wax thermostats are more reliable and last longer.


Most of the time, we’re either at work or on the road, with barely a third of our waking hours spent at home. Depending on the time of day or the house’s temperature, we usually have a programmer or thermostat in our homes that controls the heating. However, it’s a primitive system at best. ” In order to prevent a cold house, many of us just turn the heat up all the way, squandering a lot of energy and money in the process. This is the issue that the most recent generation of smart room thermostats is intended to address. By observing and mimicking how you adjust the temperature manually throughout the day and comparing that to objective measurements, they can build a trustworthy program they can follow automatically in the future. Now is the time to purchase your home’s greatest digital room thermostat from TADO.