How Does a Thermostat Work?

A thermostat is a device designed to control the operation of your heating and cooling systems. It works by measuring the home’s temperature and controlling the operation of the heating and cooling systems based upon the thermostat’s settings. Essentially, depending on the specified setpoint temperature, the thermostat turns on the heating or cooling system when the house gets too hot or too cold. Once the desired temperature is achieved in the house, the thermostat automatically turns off the heating or cooling system.

How Technology is Improving Efficiency

Since Warren Johnson’s creation of the first thermostat in 1883, modern technology has come a long way. Consumers can now simply ‘flick the switch’ to adjust the thermostat as a no cost, DIY measure to create a more comfortable climate or reduce energy bills. 

There are two main types of thermostats: mechanical and digital. Mechanical thermostats allow you to adjust the setpoint temperature by turning a dial or adjusting a lever. Digital thermometers have digital displays and allow you to adjust settings by pressing a button. Many digital thermostats are now programmable, which allow you to program a schedule that automatically adjusts the setpoint temperature at certain times of the day or days of the week. This can yield savings up to $180 a year, according to the EPA.

Some programmable thermostats are becoming even smarter. Perhaps you’ve heard about the Nest thermostat. It learns the temps you like and monitors your behavior like when you’re not at home or when you’re asleep and sets it’s own schedule. It can even connect to your home’s wi-fi allowing you to control it remotely through your smartphone.

Behavior Still Matters

Whether you have a digital or mechanical thermostat, it’s important to know how to efficiently control it. Here are some tips:

- In winter, set the thermostat to 68°F or as low as is comfortable.

- In summer, set the thermostat to 78°F or as high as is comfortable.

- Use your thermostat’s programmable settings or manually turn back the thermostat when you’re not at home or asleep*.

- During spring and fall when the temperature outside is moderate, turn your A/C off and open your windows.

- Turning on the air handler while keeping the A/C off will help distribute air throughout the house while using little energy

- If you’re on vacation or away from the house for an extended period of time:

…in the winter, turn down the thermostat to 55°F. This will lower your energy consumption while ensuring that your water pipes won’t freeze.

…in the summer, turn up the thermostat to 85°F. This will lower your energy consumption while ensuring that the humidity levels of the house don’t get too high.

A common misconception about thermostats and home temperatures is that if the heat level is too low, then the heat within the home will escape easily. In fact, the opposite is true. The greater the difference between indoor and outdoor temperatures, the faster heat will escape from the house. So in winter, the lower the interior temperature, the slower heat will escape. This also applies to the summer conditions and thermostat settings.

Another misconception is that setting the thermostat setpoint to extremes will heat or cool the home faster. The reality is that no matter the setpoint temperature, the heating or cooling systems work at the same speed and at the same efficiency. The only difference is how long the systems will run in order to reach the setpoint temperature of the thermostat. In fact, frequently straining your system with long run times will shorten its lifespan and may even cause damage.

Click the link to view last week’s blog All About Energy Audits or check back next week for more energy saving tips.

*If you heat your home with a heat pump, don’t adjust your thermostat in winter unless you can ensure that the setpoint temperature never jumps more than two degrees at a time. See our blog post The Truth About Heat Pumps to find out why.