What is a smart thermostat and how does it work?

Anyone who lives in New England understands the importance of having a thermostat that actually works. If you live in an older home or apartment, you may have a bulky thermostat with programmable settings that mostly work but don’t effectively regulate temperature. Or, you’ve got a clunky dial that allows you to manually change the temperature, but only when physically standing in front of it.

Over the last decade, there’s been a surge in the market for people seeking better ways to control their home environment, whether to humidify or dehumidify, heat or cool, or simply purify the air.

Speaking specifically of temperature, you may or may not be aware of smart thermostats. These devices can make a world of difference in your home by helping you save on your energy bill and providing a more comfortable home environment tailored to your individual comfort.

Popular brands with a footing in the marketplace include Nest and Honeywell, but you may also be aware of others like Emerson Sensi, Ecobee, Cync, and Wyze.

So, what makes them smart? How are these home devices different from standard thermostats you can get for less than $20? We’ll dive into what makes a smart thermostat tick, what other devices in your home they’re compatible with, and whether you can install it yourself.

What is a smart thermostat?

Just like the thermostat you’ve got now, a smart thermostat allows users to change the temperatures in their homes. Many devices come with touch screens that replace knobs and buttons, providing a more user-friendly interface. Smart thermostats also come with Matter-enabled mobile apps that allow you to remotely adjust settings, and they’re compatible with voice-controlled personal assistants, like Amazon Alexa and Google Assistant.

These smart home devices prioritize user experience, making them intuitive and easy to use. Some can even learn your patterns and adjust heating settings to provide optimal energy saving in your home.

How does a smart thermostat work?

Smart thermostats are wired into a home’s HVAC system, typically through what’s called a common wire, or C wire. Older homes may not have a C wire, so while you can still get a smart thermostat, you’ll need to have the house wired for a C wire first. This wire is integral for properly installing a smart thermostat, as it connects the device to your HVAC system without messing up wiring for the furnace or other appliances in the house.

Smart thermostats connect to your home’s Wi-Fi, then allow you to access the device’s unique temperature settings, which may include:

Mobile control: Most smart thermostats have touch or digital screens that allow you to change temperatures, but they also come with mobile apps designed to allow users to control the home environment from the couch or the car. This is a great feature if you like coming home to the perfect temperature or adjusting the settings without having to get out of bed. You can also use mobile apps to set programs or remotely monitor your home’s temperature while you’re out of town.

Humidity controls: Have your ever woken up with your home's windows covered in moisture? With a smart thermostat, you can monitor your home's humidity and even set an alarm to go off on your phone if it changes.

Geofencing capability: Smart thermostats allow you to program your thermostat to run during particular times of the day, but what about those days when you want to break free of your routine? Geofencing allows you to go on an impromptu trip without stressing about your energy bills. Using geotracking technology, some smart thermostats can register when you’ve left the house and then adjust the home’s temperature accordingly to ensure you remain efficient with your energy usage.

Connection to smart speakers: Our favorite smart devices are the ones that can speak to each other. Many thermostats can be paired with smart speakers you may already own. Most smart thermostats should be compatible with at least one, if not all, top-selling smart speakers. If you’re unsure, consult the user manual that came with your thermostat.

Can I install a smart thermostat, or does a professional need to?

This really comes down to your familiarity with HVAC systems, comfort level around electrical wires, and ability to easily follow the directions that come along with the thermostat. Start by removing the old thermostat and checking if you have a C wire. Many smart thermostats claim they can operate without one, but the connection would not be optimal. Essentially, this means your thermostat may run, but its Wi-Fi connectivity and power connection might not be fully stable, which is the opposite of what you want from any smart device.

If you can identify the C wire (which should be labeled as such), you can probably install the smart thermostat on your own. But if your house doesn't have a C wire, we recommend hiring a professional to come out and install it. It’s incredibly hard and expensive to fix faulty wiring, so if you don’t know what you’re doing, call the pros.

Is buying a smart thermostat worth it?

There are lots of benefits to owning a smart thermostat, but are there enough to justify its cost and the potential cost of installation?

Ideally, a smart thermostat should pay for itself after a year or two with the money you save in energy costs. Since the thermostat can track when you’re home and when you need the most heating, it can ensure efficiency in your home and prevent unnecessary spending on heat. Plus, these energy-efficient appliances are good for the environment, meaning you may be eligible for a rebate for simply owning one.

If you’re a homeowner, the temptation to purchase a smart thermostat may be greater than if you’re a renter. Can you even install a smart thermostat in an apartment? It depends on whether you can find one that doesn’t operate with a C wire or one that your landlord will approve.

Overall, if your current thermostat is on its way out, it’s worth upgrading to a smart thermostat that can last for the next 20 to 30 years, providing you with a variety of benefits to improve your quality of living. If your thermostat works perfectly fine, a smart thermostat may be a good investment if energy efficiency is a priority.