What is a Thermostat?

For the purposes of HVAC, a thermostat is a regulating device which is used in any system that heats or cools to a set temperature. Thermostats sense the temperature of a room or physical system and perform actions so that the system's or area’s temperature is maintained near a desired setpoint.

How Does a Thermostat Work?

The science behind the thermostat is simple. As things heat up, they expand, and as things cool down, they contract. This is known as thermal expansion, and mechanical thermostats will use this to switch on and off an electrical circuit. You’ll commonly find bimetallic strips and gas-filled bellows in most thermostats.

There are two main types of thermostats: mechanical and digital (which also includes smart thermostats). A mechanical thermostat uses two strips of metal, laminated together in what’s called a bimetallic strip in the thermostat’s sensor. As the temperature of the house goes up and down the two different types of metal expand and contract, and this switches the electric circuit connected to your heating system on and off. Digital thermostats have much more sensitive electronic sensors that read the temperature of the rooms and control the heating to keep it within 1 degree of your chosen setting. Digital thermostats use a simple device called a thermistor to measure temperature. This is a resistor which allows electrical resistance changes with temperature. A microcontroller measures the resistance and converts that number to an actual temperature reading.

How Long Do Thermostats Last?

Digital thermostats tend to have about a 10-year lifespan but are usually replaced sooner due to innovations in the market. Non-programmable or mechanical thermostats have become outdated and aren’t as accurate as digital or smart thermostats. The temperature readings can vary as much as 5 degrees. Many people are replacing them with programmable (or learning) thermostats. 

Signs Your Thermostat Needs Replacement 

• Heating or cooling system will not turn off or on – Your thermostat’s main function is to communicate with your HVAC. If your air conditioning or heating is not taking the prompts of the thermostat, the problem may be with your thermostat. 
• The temperature reading is incorrect – The sensor in your thermostat can malfunction from old age, misuse, or manufacturing defect.
• Recent spike in your energy bill – If a thermostat is not properly reading the temperature, it can cause the HVAC to work over time and use more energy than it should. 
• Frequent temperature fluctuations – A malfunctioning thermostat may not be able to maintain a setting, and may shift temperature settings with no warning. 
• Thermostat is 10 years old or older – As with any system, eventually, your thermostat will become outdated. Mechanical thermostats have become outdated and are usually replaced by programmable (or learning) thermostats.

Expert Installations by Skilled Technicians

When you choose Levco’s full team of certified installation experts, you not only get access to the best technicians for all your heating and cooling system needs, but you also gain access to our network of top equipment manufactures. We work with all the best brands in the industry and can help you choose the optimal solution for your project. For thermostats, we proudly work with Honeywell, Nest and Ecobee. From small equipment replacements to brand new facility or home build-outs, there is no job too big or too difficult.

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FAQs About Thermostats

What temperature should I set my thermostat for when away?

If you are going away on vacation, experts recommend adjusting your thermostat by about 7-10 degrees to conserve energy while you're gone. There's no use spending money on heating and cooling when no one is home.

What is the healthiest temperature to keep your house?

Depending on the season, the ideal house temperature for both comfort and efficiency is between 68 to 78 degrees Fahrenheit. In the summer, the recommended thermostat setting is 78 degrees F. In the winter, 68 degrees is recommended for energy savings. However, these temperatures aren't perfect for every situation or person and in the end, it depends on individual comfort levels.

What does the auto button do on a thermostat?

AUTO means the fan turns on “automatically” ONLY when your system is heating or cooling your air. When the thermostat reaches your temperature setting, the system, including the blower fan, shuts off. This is the most energy efficient option.