Thermostat Buying Guide
Getting the Temperature Just Right

When it comes to controlling the temperature in your home, a good thermostat can both warm your heart and cool your jets as needed.

With a smart thermostat, you can save $50 a year on your energy bills, according to Energy Star, and some thermostat manufacturers claim those savings can reach $100 or more. Before there were smart thermostats, of course, non-connected, programmable thermostats provided energy savings, and they still do.

But for years the problem has been that they're too difficult to program for many consumers. For that reason, Energy Star stopped certifying the entire product category in 2009. In fact, according to a 2015 study, 40 percent of programmable thermostat owners didn’t use the programming feature to set schedules. That’s a problem because a thermostat can only save you money on your energy bill when it’s set back and using less energy. You can do that manually every time you go to bed or leave the house, or program your thermostat to do it for you on a schedule.

Enter Smart Thermostats

Thermostats have since gotten much less daunting, thanks largely to the advent of smart thermostats. They tend to have simple controls and touchscreen displays that make programming easier. More important, smart thermostats connect to the internet via WiFi, allowing you to change the temperature at home through an app on your smartphone wherever you happen to be—as easily as you would check your bank balance. Smart thermostats can also factor in your local weather forecast and “learn” your temperature preferences through sensors and computer algorithms. The idea is to move beyond programming altogether.

Energy Star took another look recently and launched a certification specifically for smart thermostats in January 2017. The packaging label makes it easy for you to know which smart models will help lower your energy bills. As of October 2017, eight smart thermostats have received Energy Star certification, and that number will likely grow.

Some of the user interface improvements created for smart thermostats have also trickled down into non-connected, programmable thermostats, finally making some of them a relatively easy-to-use option for consumers who don’t want an internet-connected model.

How CR Tests Thermostats

At Consumer Reports, we’ve tested hundreds of thermostat models over the years. And while once upon a time they weren’t very accurate, most are able to keep rooms close to the set temperature. It’s for this reason that we no longer test manual thermostats—all they do is hold a set temperature.

With temperature accuracy a given, CR focuses our testing on ease of use—taking note of how simple each thermostat was to set up and adjust without instructions.

For smart thermostats, we take testing quite a few steps further. We factor in smart features like alerts, app control, and geofencing. We also account for machine learning and automation features, which allow smart thermostats to learn your habits and routines to adjust temperatures for you. And with the growing popularity of virtual assistants, we consider voice control with Amazon Alexa, Google Assistant, and Apple’s Siri, if those integrations are available. These criteria factor into our unique Smart IQ and Automation scores for smart thermostats.

Our test engineers then take all of this data and incorporate it into our overall scores for both smart and non-connected thermostats. 

Thermostat Types

The iconic round thermostat with a dial is a relic, though Honeywell still makes a version. Today's models have bright displays and easy to use interfaces.

Photo of a thermostat without remote access capabilities.

Programmable Thermostats

With no connection to the internet, these models require you to set the temperature, as well as select the heating or cooling cycle of your HVAC system, on the unit itself. Most feature a digital interface with the option to schedule or automatically adjust your home’s temperature based on times you specify.

Pros: Cost-effective. Most models allow you to set different temperatures for multiple times of the day and/or every day of the week.

Cons: Lack the convenience and flexibility of automation, remote control, and voice control.

Programmable Thermostat Ratings
Photo of a thermostat with remote access capability.

Smart Thermostats

These models allow you to remotely control your thermostat via your smartphone or computer. Some employ multiple sensors to monitor temperatures in various parts of the home for more balanced heating or cooling. Some models track your temperature preferences and use that data to optimize your heating and cooling schedule.

Pros: Energy-efficient and convenient. Offer finer control of your HVAC system to reduce your carbon footprint, lower your home's energy usage, and save money. Able to automate your heating and cooling with little to no manual input.

Cons: Expensive. Not every smart thermostat works with every home’s existing HVAC system.

Smart Thermostat Ratings

How To Choose A Thermostat

1. Decide whether you’re interested in a non-connected, programmable thermostat or a smart thermostat.
If all you care about is simple programming, a non-connected thermostat will suffice, and they’re much more affordable. If you’re interested in controlling your thermostat with your voice or an app, or in giving up control and letting it learn your habits, then you should consider a smart thermostat. To narrow your choices, factor in smart features (such as geofencing), price, and attributes that matter to you, such as color, size, or style.

2. Consider Your HVAC System
Nearly all of our tested models work on common heating and cooling systems, but check the packaging for exceptions. This is especially a concern with smart thermostats, as not all models support all types of HVAC systems. For example, the Nest Thermostat E doesn’t support two-stage heat pump systems, but the Nest Learning Thermostat does. And if you have separate heating and cooling systems, you may need to install a separate thermostat for each system, as well as each zone of heating and cooling.

3. Scope Out Your Wiring
You’ll also want to open up your existing thermostat to see what kind of wiring you have. Most non-connected, programmable thermostats will work with as few as two low-voltage wires (common in older heating systems), but newer thermostats often require a common wire, or C-wire. The C-wire provides continuous power for features like displays and WiFi. If you aren’t sure if you have a C-wire, you’ll need to consult an HVAC technician.

If you know you don’t have a C-wire, but you really want a smart thermostat, you have a few options:

• Choose a model with a power adapter or power extender that allows you to add a C-wire to your system, like the Ecobee.
• Buy and install a third-party add-a-wire adapter.
• Pick a model from our ratings that doesn't require a C-wire (look under the Features & Specs tab in our ratings table). Both Nest and Emmerson claim you don't need a C-wire for many systems, but some HVAC professionals caution against this arrangement, as it can damage your mechanical equipment.
• Have a C-wire professionally installed.

A Word About Installation
Most non-connected thermostats can be wired easily into your heating and cooling system. Simply take a photo of the wired connection on your current thermostat so you know which wires go where and connect those wires to the corresponding ports on your new thermostat. Many smart thermostats will also include detailed installation instructions or video walkthroughs to make the process easier.

TIP: Install a thermostat on an interior wall that's centrally located, and away from vents and other sources of drafts or direct sunlight, which could distort temperature readings.



Thermostat Features

The features on programmable and smart thermostats vary from model to model. We've identified some that make it easier to control the thermostat, keep you comfortable, and allow you to maximize your energy savings.

Thermostat Brands

Honeywell’s Home and Business Technologies (HBT) division is the largest thermostat manufacturer in the industry, making manual, programmable, and smart models. Honeywell's thermostats range in price from $20 to $250 and can be purchased at Home Depot, Best Buy, Lowe’s, Amazon, dealers, and many other stores.
Venstar is one of the largest thermostat manufacturers and suppliers. Venstar thermostats range in price from $40 to $190 and are sold at Amazon, specialty online retailers, and plumbing retailers.
Based in Toronto, Canada, Ecobee is one of the youngest—but fastest growing—brands in the industry. Ecobee only makes smart thermostats, which range in price from $170 to $400. Ecobee thermostats are available at Home Depot, Best Buy, and Amazon.
Introduced in 2011 and now owned by Google parent company Alphabet, Nest is one of the fastest-growing of the new thermostat brands. They introduced the industry’s first “learning” thermostat, which disrupted the industry. Nest thermostat prices range from $140 to $240 and are available at Home Depot, Lowe’s, Best Buy, Amazon, and many more retailers.
Carrier is an arm of United Technologies Corp. and one of the largest HVAC brands in the U.S. Carrier thermostats are usually only available from HVAC dealers, but some models like the COR smart thermostat are also available at retailers such as Home Depot and Amazon. Carrier thermostats range in price from $150 to $600.
Lennox is a large, national HVAC company and sells its products through a network of over 6,000 dealers. Lennox thermostats range in price from $160 to $600.
Schneider Electric is a European brand that is new to the U.S. The company sells its Wiser Air smart thermostat and markets it as a learning thermostat. The Wiser Air costs $200 and is available at Home Depot, Walmart, Amazon, Best Buy.
Lux is one of the oldest thermostat manufacturers in the U.S. It manufactures both electronic (programmable & smart) and mechanical thermostats. Lux thermostats are sold at Home Depot, Lowe’s, and other hardware stores. Lux models range in price from $30 to $150.
Emerson’s Climate Technologies division manufactures thermostats. The company also sells thermostats under the White Rodgers brand. Emerson produces both mechanical and electronic thermostats, including its Sensi line of smart thermostats. Prices range from $30 to $200 and Emerson models are sold at Home Depot, Lowe’s, Amazon, and other hardware stores.
LockState is a small U.S. brand offering electronic thermostats. LockState thermostats range in price from $75 to $250. Models are available at Home Depot, Amazon, and plumbing retailers.
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