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What is a smart thermostat?

Smart thermostats explained: How they work and how they save you money

In recent years, many people have turned to smart thermostats to remotely adjust the heating and cooling in their homes. Not only do they look more elegant and sophisticated than their non-smart counterparts, but they offer a lot in terms of efficiency, convenience, and features. Best of all,  they can help you save on heating and cooling costs.

Read on for a closer look at what they are and how they operate.

Further reading

What exactly is a smart thermostat?

A smart thermostat is a thermostat that can be controlled with a phone, tablet, smart speaker, or other internet-connected device. Smart thermostats typically allow you to schedule your desired temperature settings, and you can also incorporate them into home automation systems.

What else can a smart thermostat do?

Depending on the specific model, smart thermostats can offer a plethora of cool features. Some thermostats, like the Nest Learning Thermostat, can learn your heating and cooling preferences and automatically adjust based on said learning. Many of the best smart thermostats have diagnostic features, which can detect when there’s a problem with your ducting or HVAC system. Your smart thermostat may also be able to remind you of when it’s time to perform system maintenance, like when it’s time to change your air filter. Additionally, your thermostat may be able to provide you with details regarding your energy consumption.

If you opt for an Ecobee 4 or Ecobee SmartThermostat, it has Alexa built in, so you don’t necessarily need to purchase a separate smart speaker. Some thermostats also include room sensors that can measure the temperature in a specific room or area of the home and heat or cool that room specifically based on the temperature in that local area, reducing hot or cold spots in the home. If your thermostat has geofencing, it can recognize when you enter the home and save on heating and cooling cost when you’re away from home.

How does a smart thermostat work?

Terry Walsh/Digital Trends

To understand how a smart thermostat works, you’ll first need to understand how regular thermostats works. A thermostat uses temperature to determine when it needs to turn the fan and AC or heat on and off. It actually works kind of like a light switch, except it incorporates temperature and into the equation (to help it determine when to turn the fan, heat, and cool on and off). A typical thermostat has a hot wire, a common wire, a wire that connects to the fan blower, and wires that connects to your HVAC system for heating and cooling. It may also have additional wires for things like auxiliary heat, emergency heat, two-stage heating or cooling, or wires for systems that have separate or standalone AC or heat. When you set a specific temperature on your thermostat, the fan and heat or cool shut off once the internal thermometer reaches the desired temperature. Here’s how to test your thermostat.

Smart thermostats work similarly, except they also connect to the home’s Wi-Fi. This allows you to change the thermostat’s settings remotely using a companion app. When you input a temperature setting into the app, it transmits that setting through your Wi-Fi network to the thermostat, and the thermostat then sends that signal to the blower and HVAC system. When you use a smart speaker like Google Home and say “OK Google, set temperature to 70 degrees,” the Google Home app communicates the command to the thermostat’s companion app, which travels through your Wi-Fi network to the thermostat. It all happens so quickly that you’ll probably never notice all of components involved in simply adjusting the temperature in your home.

How does a smart thermostat save you money?

Smart thermostats save you money simply by cooling and heating the home only as much as needed. Using features like learning, scheduling, geofencing, by diagnosing problems with the system, and by reminding you of when it’s time to perform maintenance, your HVAC system runs more efficiently and uses less energy. Room sensors can also reduce energy consumption by heating and cooling specific areas more accurately.

What’s the difference between a smart thermostat and a programmable thermostat?

A programmable thermostat allows the user to input schedule and program settings. A smart thermostat is a step up from a programmable thermostat, as it typically allows the user to program desired settings and it connects to Wi-Fi for more advanced features and functionality.

What are the requirements for installing a smart thermostat?

Most homes with modern HVAC systems can upgrade to a smart thermostat, provided there’s a Wi-Fi connection. However, given that there are a variety of different types of heating and cooling setups, it’s prudent to confirm your system’s compatibility before purchasing a smart thermostat. You may also need to have a C-wire (or common wire) in your existing thermostat’s wiring setup. If you don’t have a C-wire, you can purchase a smart thermostat that includes an adapter kit.

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