Let’s get the basics out of the way. What is a smart thermostat, exactly?

Well, it’s not as clear cut as you might think. Some of the options on this list actually push the boundary.

For example, the Google Nest Learning Thermostat is very clearly a smart thermostat. It’s touch screen, integrates smoothly with modern tech and other smart devices, and can learn your behavior.

But some of the other options on this list, like the Orbit 83521 Clear Comfort Programmable Thermostat, don’t even look like smart devices. Orbit and GoControl’s devices look like ordinary thermostats, frankly.

But it’s not all in the looks, or having a touch screen. Orbit’s thermostat can be programmed—that’s not something traditional thermostats could do. GoControl’s can be linked to your phone, so you still functionally get smart features, just via your other devices.

There’s a general distinction that can be made here, using the examples given above, between “programmable” thermostats and “learning” thermostats.

Learning thermostats adapt automatically. Even if they don’t exactly learn your behavior, they can make basic changes by themselves—like geofencing (more on that in a sec).

Programmable ones need you to set schedules.

And of course, some can do both. But typically a smart thermostat will err more on one side than the other.

So what are the benefits of a programmable thermostat?

For one thing, they’re usually more affordable. And if you have a fairly regular schedule, your programming of the thermostat will still make it effective at saving money the way a smart one would, so it’s even more cost-effective over time.

Another benefit is that these often don’t require internet connections, which can make them more reliable, and programming may not be too difficult.

The downsides? While programmable thermostats CAN have voice control through integrating with compatible devices, they usually don’t. Most features we consider “smart” in the current context won’t be available.

With learning thermostats, you probably can infer the main strengths and weaknesses based on the ones for programmable thermostats above.

You can get finer-tuned temperature adjustments with less hassle. Learning behavior allows for a lot more flexibility, which can be great even if you have a regular schedule anyway.

Even when learning behavior is more limited, voice commands are both handy and luxurious. Being able to control the smart thermostat from your phone or computer is also a very practical ease-of-use feature.

As for the downsides, a learning smart thermostat will cost more, may require other smart devices for full functionality, may be less reliable if WiFi connectivity is an issue in your area, and some have trouble integrating with HVAC systems.

However, some would argue that the finer-tuned energy changes from a learning thermostat can help you save even more than a programmable thermostat, and that this should affect your view of the cost.

So when you look for a smart thermostat, it’s best to consider carefully how “smart” you actually want it to be.

That includes considering the other smart devices you already have in your home, or plan to buy:

The smartest thermostats work best, not only when you have a smartphone and/or tablet, but when you have a smart speaker, for example, or additional smart sensors from the same company.

It’s not a prerequisite, but some smart thermostats may pay off the most when you have additional smart products.

You’ll probably hear of “geofencing” either in reviews or product descriptions. Basically, geofencing is when a smart thermostat uses your phone’s location to figure out if you’re home or not.

When you leave your home, the geofencing feature will be used to adjust your home’s temperature—either to reduce the heat to save energy, or to keep the house warm for when you come back.

Now, how important is that? Well, obviously that’s your call.

But generally speaking, this is a more important feature to those who leave their home frequently for work, or who have to leave at random times. In such cases, geofencing can make your smart thermostat a lot more useful and even more cost-efficient.

But if you work from home, or if you just don’t really care that much, then it’s probably not worth paying too much attention to in your smart thermostat search.

It should go without saying, by the way, that if your smart thermostat is programmable-only, it probably won’t have a geofencing feature. It’s a point worth considering if you’re not sure if a programmable or learning thermostat is better for you.

If geofencing is something you want to prioritize, there’s good news and bad news:

The good news is that it’s a pretty common smart thermostat feature.

The bad news is that not all of those geofencing features work that well. So you’ll need to do your own research into which options have the best geofencing.

It’s not as fun to consider as “smart” features, but it’s pretty important in choosing the right smart thermostat.

The main issue here is whether or not your smart thermostat will connect to your home’s HVAC system—that means heating, ventilation, and air conditioning.

Specifically, most advanced smart thermostats will require a C-wire (or “common wire”) connection to your home’s HVAC system. Newer homes may have that, but older ones may not.

If your home does, there’s a fair chance you can just install the thermostat yourself. Most are fairly easy for an average person to install and come with beginner-friendly instructions.

But if your home doesn’t have a C-wire, or if you’re just cautious, you’re not out of luck. You can hire an electrician to install one. If you feel confident, you can even buy a C-wire adapter and plug everything in yourself—though of course, do your own research and be careful!