woman adjusting smart thermostat

Buying Guide: Smart thermostats

Find out what features and installation info to look for when shopping for a smart thermostat.

When it comes to saving on energy costs – and staying comfortable – a smart thermostat can do wonders. While manually programmable thermostats can help you save energy, smart thermostats take year-round savings to the next level. In fact, a smart thermostat can help you save about eight per cent on your yearly home energy costs for heating and cooling, according to Natural Resources Canada. 

Smart thermostat models vary in price, depending on their features and how easily they integrate with other smart technology you may have in your home. Regardless of the model you choose, in most cases, you won’t need to hire a professional to install your smart thermostat. However, it’s still important to install yours safely so follow the product instructions carefully. Most manufacturers also have step-by-step tutorials for installation on their websites, so be sure to consult these as well. 

If you’re ready to go shopping, here’s what to keep in mind.

Pick the features that make sense for you

At a basic level, all smart thermostats “learn” from your habits and then automatically adjust your home’s temperature accordingly. Specifically, they automate adjustments to your heating or cooling based on your schedule, preferences and location, including through “away” modes that conserve energy when you’re not at home. How each model goes about doing this can differ. Here are a few features and technologies you may see described when reviewing various models.

Discover if you are eligible for a smart thermostat at no cost.

Learn about the Energy Affordability Program.

App controls and alerts

Every smart thermostat model will have an accompanying mobile app. You can often use these apps to control the thermostat settings remotely. You may also be able to get alerts, such as furnace maintenance reminders or when there is a sudden change in temperature. Many smart thermostat models offer insight reports so you can better understand how you’re using energy and how to save it.



Some smart thermostats use geofencing technology to help you conserve energy. Based on the location data from your smartphone, the thermostat will adjust your temperature when you’re away from home or close to returning. However, if you largely work from home and have a relatively predictable schedule, this may not be the most useful feature for you. Other models may rely on proximity sensors to gauge whether you’re at home and adjust the temperature accordingly.


Remote temperature sensors

Many smart thermostat models are compatible with remote room sensors to monitor and better regulate your home’s temperature, which may help you save energy and stay more comfortable. Some models include these with your thermostat purchase, but if not, you will have to purchase them separately. These sensors are especially useful for older homes that may have inconsistent airflow (with some areas of the home getting more or less heating and cooling) and for homes with thermostats that aren’t ideally placed for temperature readings.

You can start by placing a temperature sensor in your coldest room and one in the warmest room to average your home’s temperature. From there, you can set up as many sensors as you want. The smart thermostat will use the temperature readings from the sensors in each room, instead of the spot where the thermostat itself is placed, then adjust the heating and cooling accordingly, which may help you feel more comfortable.

Voice control

Many models are also compatible with voice assistants or include voice controls, so you can have hands-free control over your thermostat.

Smart home integration

If you have other smart devices throughout your home, you may want to opt for a smart thermostat that is compatible with smart home kits or systems. Some smart thermostat models will integrate with existing systems, so you can control all your smart devices from one app, including your doorbell, lighting, speakers, smart ceiling fans and more. This kind of interoperability can help you save energy. If you have home monitoring devices that show when a window is open, for example, your smart thermostat could turn off your air conditioner. However, if you don’t feel you’ll get use out of connecting your smart thermostat with other smart devices, opt for a more basic model instead.

ENERGY STAR certification

As with other home appliances, ENERGY STAR certification of smart thermostats gives you confidence that the model you’re choosing is energy efficient. ENERGY STAR has certified dozens of models, and its online tool allows you to compare model features.

Compatibility with your HVAC system

Along with looking at price and features, you’ll need to make sure the smart thermostat you are considering is compatible with your home’s HVAC system. Not all models support every type of heating and cooling system, so make sure to check the compatibility information on the product label or website before you buy. Some HVAC systems may even require a smart thermostat from a specific manufacturer, although many will work with several models.

Installing your smart thermostat

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Before disconnecting your current thermostat, take a picture of the wiring so you can see how everything is connected.

Typically, installation will include these four steps:

  1. turning off the electricity to the thermostat from your circuit breaker,
  2. removing the old thermostat,
  3. installing a wall plate for mounting the new smart thermostat, and
  4. connecting your new smart thermostat to the existing wires before turning the power back on. 

Before installing your thermostat, you will need to look at your wiring. Be sure to always turn off the electricity to your thermostat before disconnecting anything or looking at wiring. Most manual or programmable thermostat models use two low-voltage wires. However, many smart thermostat models will also need to be connected to your common wire, or C-wire, which gives it continuous power.

The C-wire is often visible and labelled on the panel behind the existing thermostat. If you don’t see the wire there, you can check whether there is a labelled C-wire inside your furnace. If there is a C-wire inside the furnace, it would indicate that the end of the wire that would connect to the thermostat is probably hidden from view in the wall behind the thermostat panel.

If you can’t find your C-wire either behind the wall or inside the furnace, you may not have one. If that’s the case, you may need to consult a qualified HVAC professional, or find a smart thermostat model that will work without one. Not every smart thermostat model requires a C-wire, and some smart thermostat models may include power adapters or extenders that let you add a C-wire to your system.

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If your home has spotty Wi-Fi, consider investing in a range extender or Wi-Fi mesh technology to improve the signal throughout your home.

Keep design in mind

Finally, think about whether you like the aesthetics of a given smart thermostat model, both from a user experience perspective and from how it will look in your home. Pay particular attention to the display to see whether you find it readable, attractive and intuitive for your needs.

The Energy Affordability Program offers smart thermostats for qualified Ontario homes at no cost.

See if you’re eligible today.