Smart thermostats do more than let you adjust the temperature from your phone. They use sensors, schedules, and internet connectivity to trim heating and cooling waste without making you uncomfortable. For many households, that can mean a noticeable difference in monthly bills, because heating and cooling eat up a large share of home energy use.
How Smart Thermostats Save Energy
According to ENERGY STAR, heating and cooling account for almost half of the average American household’s annual energy bill. A smart thermostat that earns the ENERGY STAR label has been independently certified, based on actual field data, to deliver energy savings. While each model uses slightly different features, the core idea is the same: the thermostat automatically adjusts temperatures when you do not need full heating or cooling, so you use less energy without thinking about it.
ENERGY STAR explains that common features in certified models include the ability to learn your temperature preferences and build a schedule that shifts to energy-saving set points while you are asleep or away. Geofencing lets the thermostat detect when you have left home and set back the system, then resume a comfortable temperature as you return. Remote control through a smartphone app gives you the flexibility to adjust settings from anywhere with an internet connection. Certified thermostats also enter a low-power standby mode when inactive and receive over-the-air software updates that keep energy-saving algorithms current.
These features work together to reduce the time your heating or cooling system runs at full output. Because the thermostat can sense occupancy and learn routines, it avoids conditioning an empty house. ENERGY STAR notes that certified smart thermostats are also designed to be compatible with programs offered by some local utilities, which may provide incentives to homeowners who help manage grid reliability. If you are shopping, look for the ENERGY STAR label to confirm the model meets the program’s key product criteria.
Checking HVAC Compatibility
Even the most advanced thermostat will not save energy if it cannot communicate with your heating and cooling equipment. ENERGY STAR’s buying guidance stresses that you should make sure the smart thermostat you purchase is compatible with your heating and cooling system. For the very highest efficiency equipment, such as an air conditioner rated at 20 SEER or higher, you may want a controller from the same company. Always consult the thermostat maker’s compatibility checker or your HVAC professional before you buy.
Wi-Fi connectivity also matters. ENERGY STAR recommends placing the thermostat reasonably close to your router to prevent periodic disconnections. If the distance is too great, a Wi-Fi range extender can improve overall connectivity. A stable connection is essential for remote control, geofencing, and receiving software updates that keep the device running efficiently. For more guidance on matching devices to your setup, see our compatibility guides.
Matter and Smart Thermostats
Many newer smart thermostats support Matter, a connectivity standard that aims to make smart home devices work together across different platforms. Google’s setup guide for Matter-enabled devices explains that Matter thermostats can be controlled locally over your home Wi-Fi or Thread network, without always needing to connect to the cloud. Commands sent from inside the home are carried out directly on the local network, which can reduce delays and keep basic functions working even if the internet goes down.
To set up a Matter thermostat with Google Home, you need a Matter-enabled hub, a home Wi-Fi network with IPv6 enabled, and a phone that supports Bluetooth Low Energy 4.2 or higher. The Google Home app can scan a QR code on the device and walk you through pairing. Once connected, the thermostat can be shared with other Matter-certified apps, such as Apple Home or Amazon Alexa, using the Multi-Admin feature. This means different people in the home can use the voice assistant or app they prefer, and the thermostat’s status stays in sync across platforms. For a deeper look at how Matter compares to other smart home standards, read our article on Matter vs Zigbee vs Thread.
If you are building a smart home from scratch or adding devices gradually, starting with a Matter-compatible thermostat can simplify future expansion. Our smart home for beginners guide explains which device types to consider first, and the smart thermostats category page lists more resources for choosing and setting up a thermostat that fits your home.
Securing Your Smart Thermostat
A thermostat connected to the internet is part of the broader Internet of Things, and like any connected device, it needs basic security attention. The Cybersecurity and Infrastructure Security Agency (CISA) advises that you evaluate your security settings, ensure you have up-to-date software, connect carefully, and use strong passwords. These steps apply directly to smart thermostats.
CISA points out that many devices ship with default passwords that are easily found online and offer no real protection. Changing the default username and password to something unique is one of the most effective first steps you can take. The Federal Trade Commission (FTC) echoes this advice, adding that you should not reuse a password from another account. If the thermostat or its companion app offers two-factor authentication, the FTC recommends turning it on.
Both CISA and the FTC stress the importance of keeping firmware and apps updated. Manufacturers issue patches when they discover vulnerabilities, and applying those patches promptly helps close security gaps. The FTC also suggests disabling features you do not use, such as remote management if you never access the thermostat from outside your home. Older devices that are no longer supported should be disconnected from the network, because outdated security can create a weak point.
Your home router is the gateway for all connected devices. The FTC recommends changing the router’s default administrative username, password, and network name, enabling encryption, and regularly checking for hardware and software updates. A guest network can also separate smart home devices from computers and phones that store sensitive information. For more on securing the broader smart home, visit our smart home section and the smart home setup guide.
Frequently asked questions
Do smart thermostats really lower energy bills?
ENERGY STAR states that certified smart thermostats are independently verified to deliver energy savings based on actual field data. Because heating and cooling account for nearly half of the average household energy bill, automatically reducing run time when you are asleep or away can lead to noticeable savings. The exact amount depends on your climate, home, and habits, but the certification confirms the device meets established efficiency criteria.
Can I install a smart thermostat myself?
Many smart thermostats are designed for do-it-yourself installation, but you must first confirm compatibility with your heating and cooling system. ENERGY STAR recommends checking the thermostat maker’s compatibility requirements. If your system uses high-voltage wiring or a proprietary communicating protocol, professional installation may be necessary. Always turn off power to the HVAC equipment at the breaker before handling any wiring.
What if my thermostat loses its internet connection?
ENERGY STAR suggests keeping the thermostat reasonably close to the router and using a Wi-Fi range extender if needed. A Matter-enabled thermostat can still respond to local commands through a hub even without an internet connection, according to Google’s support documentation. Check your thermostat maker’s documentation for what works offline; remote access and cloud features need a connection.
For more information on choosing, installing, and using a smart thermostat, browse our smart thermostats category.
