Skip to main content

What is a smart thermostat?

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

As utility bills continue to rise, many homeowners have turned to smart thermostats as a way to cut their expenses. Not only do they look more elegant and advanced than a standard thermostat, but they come with a variety of powerful features that can help optimize your heating and cooling schedules — and save you a bundle of cash in the process. But what exactly is a smart thermostat, and why should you consider adding one to your home? Here’s a closer look at these versatile gadgets and how they stack up to the competition.

What exactly is a smart thermostat?

Image used with permission by copyright holder

A smart thermostat is a thermostat that can be controlled with a phone, tablet, smart speaker, or another internet-connected device. Smart thermostats typically allow you to schedule your desired temperature settings, and you can also incorporate them into home automation systems. They also tend to feature sleek, modern designs — which are a vast improvement over the clunky rectangles offered by traditional thermostats.

Recommended Videos

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 ductwork 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. Your thermostat may also be able to provide you with details regarding your energy consumption or even give you a reading on your indoor humidity levels.

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 costs 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 a regular thermostat 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 into the equation. A typical thermostat has a hot wire, a common wire, a wire that connects to the fan blower, and wires that connect 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 heating or cooling 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 the 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, as well as the ability to diagnose problems with the system and remind 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?

Image used with permission by copyright holder

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. In other words, smart thermostats make it easier to program schedules or adjust the temperature, as you can access your thermostat remotely from a smartphone app or other device.

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 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.

Adapter kits can be installed by anyone, although they do require a bit of rewiring. If you’re uncomfortable opening up your furnace and tinkering with cables, consider contacting a professional for assistance or opting for a smart thermostat that doesn’t need a C-wire.

Topics
Erika Rawes
Former Digital Trends Contributor
Erika became a professional writer in 2010, and her work is published all over the web on sites ranging from USA Today to…
The affordable Ecobee Smart Thermostat Essential is now available following debut at CES 2025
the Ecobee Smart Thermostat Essential on a green wall

After making a splash at CES 2025, the Ecobee Smart Thermostat Essential is now available for purchase. More affordable than both the Smart Thermostat Enhanced and Smart Thermostat Premium, the Essential is an affordable way to bring a bit of smarts into your home -- including Apple HomeKit integration and vacation scheduling.

Ecobee designed the Smart Thermostat Essential to be easy to use, with a large full-color touchscreen display giving you quick access to your most-used controls. However, the big draw is its built-in intelligence, as the device will slowly learn how to optimize its settings for your specific home. For example, it can detect how long it takes to heat and cool your home, allowing it to build a routine that ensures you stay comfortable regardless of the temperature outside. When paired with Ecobee Smart Sensors, it’ll even track occupancy levels and adjust your settings accordingly.

Read more
SwitchBot’s new smart shade is highly adjustable and doesn’t require a professional install
SwitchBot Roller Shade at night

First revealed at IFA 2024, the SwitchBot Roller Shade is now available for purchase. The smart gadget is designed to be highly adjustable and support DIY installation, allowing you to bring a bit of smarts to your windows without needing to contact a professional. Pricing starts at $200, scaling upwards for larger sizes and maxing out at $310 for the biggest option.

The SwitchBot Roller Shade uses interchangeable fabrics, allowing you to install blackout, full UV protection, or thermal insulating curtains. They’re also fully trimmable and expandable so you can quickly get them sized to most windows without any hassle. Windows with a width between 22.8 inches and 72.8 inches are supported, thanks to the availability of four different models that expand to various lengths.

Read more
Eve reveals its first smart light switch with dimmer functionality
Eve Dimmer Switch installed on a wall.

Eve has launched a variety of smart home gadgets over the years, including a smart plug, energy strip, and indoor camera. The company is now planning to launch its first smart light switch with dimmer functionality in March -- and with support for Matter, voice commands, and remote access, it’s looking like a solid choice for discerning shoppers.

The Eve Dimmer Switch will be one of the most expensive options on the market, carrying a price tag of $50. However, you’re getting a lot of great features for your investment. This includes Matter-over-Thread support, a premium button/rocker dimmer design for enhanced control, and the ability to sync it with Siri, Google Assistant, or Alexa to unlock voice commands. You’re also getting the ability to dim your lights, a feature missing from many other smart switches.

Read more