Skip to main content

How do smart thermostats work?

Smart thermostats are quickly becoming a staple of the modern household, offering more versatility and control when compared to traditional thermostats. But how exactly do they work? And are there any disadvantages to upgrading to the fancy new technology? Here’s a closer look at how smart thermometers work, how they can streamline your heating and cooling needs, and how they can save you money.

How does a thermostat work?

Ecobee4 smart thermostat in a kids room.
Image used with permission by copyright holder

Thermostats control how hot or cold your home gets. Before we explain the “smart” part of a smart thermostat, let’s look at the basics of thermostat operation.

Thermostats are built in one of two ways. Mechanical thermostats rely on the expansion of metal strips as the temperature rises and lowers. As the metal expands with heat, it completes an electrical circuit, which then activates your home cooling system. Similarly, your home heating can turn on when that strip gets cool, contracts, and activates a different circuit.

Digital thermostats operate under a similar mechanism. While metals physically expand with heat, they also reduce their ability to conduct electricity. Digital thermostats can accurately measure that change in conductivity with a special resistor and then activate or deactivate your home climate system accordingly.

What makes a thermostat smart?

Smart thermostats are able to communicate with more than just your home heating and cooling system. Common features include smartphone apps for remote control, internet connectivity to adjust for weather, and compatibility with voice assistants for hands-free activation. Over time, smart thermostats can learn the best time to heat and cool, which saves power by avoiding excessive usage and ultimately saves homeowners a little money on their monthly electric bills.

How do smart thermometers work?

Wyze Smart thermostat installed on wall being adjusted.
Wyze / Wyze

These extra functions require some additional hardware built into the thermostat. Smart thermostats require memory to store more information, antennae to communicate wirelessly, USB ports to communicate over a cable if need be, and a processor to handle input. This hardware will tend to be installed on a unified motherboard, similar to desktop computers. Smart thermostats typically require a common wire in the wall for power since they have many functions active in the background. The device also sports a lithium-ion battery in case of an outage or for preinstallation.

Displays will generally be higher quality on smart thermostats and integrate a touchscreen. Motion sensors are often included so the smart thermostat can detect if anyone is home and adjust the temperature of the house. Maintaining that comfort level is less necessary when nobody is home to trip the motion sensor. A microphone and speaker are sometimes present to enable voice assistants without needing to go through another device.

On the software side, mobile apps provide full remote control. Just download the app for your brand of smart thermostat from either the Google Play Store or the App Store, and follow the setup instructions. From here, you can usually set the target temperature, change presets, adjust the climate schedule, view usage history, and lots more.

Many smart thermostats are also expected to get Matter support in the coming year. This will allow them to interact with products outside of their normal ecosystem and give you additional control of your smart home. Google, for example, has already brought Matter to several devices and plans to extend its support to the Nest Thermostat in 2023.

What are the disadvantages of a smart thermostat?

The disadvantages of smart thermostats are few and far between. It used to be that cost created a significant barrier to entry, but now Amazon is offering smart thermostats for less than $100. The biggest challenge is education. Traditional thermostats only required users to turn a knob, but smart thermostats require additional setup and longer tutorials on how to take advantage of advanced functions (through apps, for example).

Older homes might also require a bit of rewiring if their current setup doesn’t include a C-wire, which can be a cumbersome process and could require a professional. Beyond those few drawbacks, there’s little reason to avoid upgrading to a smart thermostat.

Now that you know how smart thermostats work, you’re ready to start shopping for your first one.

Editors' Recommendations

Simon Sage
Simon has been publishing in tech since before the first iPhone was released. When he's not busy lighting a candle for the…
Stay cool this summer with these smart home tips and tricks
Ikea's Fyrtur smart home blind

Warmer weather is finally arriving in most locations across the country, bringing with it pool parties, summer vacations, and plenty of outdoor fun. And if you're looking for a way to make your life easier this summer, now's a great time to upgrade your smart home. From adding a smart thermostat to your home to installing a smart sprinkler system, there are plenty of ways to build a smart home that's designed to handle the summer heat.

Ready to save money on your electric and water bills? Here's are ideas on how to upgrade your smart home this summer, as well as other tips to help around the home.
Upgrade to smart shades

Read more
Google Nest Doorbell vs. Ring Video Doorbell (2nd Gen): which is better for your front door?
Ring Video Doorbell 2nd gen on doorway

Take a stroll through any neighborhood, and you're bound to encounter more than a few video doorbells. These nifty devices have grown in popularity over the years, with companies like Ring, Google, Arlo, and Wyze offering their own take on the hardware. But of all the products available today, few are as well-regarded as the Google Nest Doorbell and Ring Video Doorbell (2nd Gen).

These two devices are easy to install, capture high-quality footage, and bring an added layer of security to your front door. But which of the two is the better purchase -- the Nest Doorbell or the Ring Video Doorbell? Here's a look at both video doorbells to help you decide.
Design

Read more
Ecovacs Deebot X2 Combo vs. Dreame X40 Ultra: Which robot vacuum is best for your smart home?
The Ecovacs X2 Combo installed in a home.

The Dreame X40 Ultra and Ecovacs Deebot X2 Combo are both well-rounded robot vacuums. They bring heaps of functionality to your home, including self-cleaning docks, robots that can both mop and clean in a single run, and luxurious designs that blend with most home décor. All that doesn't come cheap, and you'll be spending well over $1,000 to get your hands on either robot. That means you'll want to carefully weigh your options before making such a hefty investment.

From vacuuming and mopping performance to pricing and additional features, here's a look at the Ecovacs Deebot X2 Combo and Dreame X40 Ultra to help you decide which is best for your home.
Pricing and availability

Read more