How to Choose the Right WiFi Thermostat: 5 Things to Consider

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Last updated: 
July 28, 2017

WiFi thermostats are the future as smart-home technology and automation evolves. The WiFi thermostat models available now are the second or third generation from most manufacturers. Also, the control and convenience they offer along with easy setup and intuitive learning technology in some are very impressive.

If you're just browsing this post and aren't familiar with the basics of a WiFi thermostat, this introduction will be of help.

wifi thermostat

WiFi Thermostat Buying Tips

With dozens of quality models available, which WiFi thermostat is right for you? These five tips focus on functionality with some information about brands. Moreover, they’ll help you select a unit that will control your system to suit your lifestyle.

1. Set a Budget or Pick Your Features

  • WiFi thermostats start at about $80 for basic models. One model is RTH6580WF Honeywell Wi-Fi thermostat with 7-day programming ($88).
  • They range to more than $400 for full-color LCD touchscreen thermostats. One of them is the Lennox iComfort with 5-day forecast ($440).

Sticking to your budget will keep you from being lured into a higher price range for features that might be interesting or convenient but not essential. Most full-function WiFi thermostat models without a touchscreen or forecast cost $135 to $250. This includes popular thermostats like Nest (+/-$225) and ecobee ($170-$250).

If your budget has range to it, then decide if you want to pay extra for touchscreen ease and functionality.

2. Ensure Compatibility with Your HVAC System

Most WiFi thermostat models work with the 95 percent of HVAC systems that use low voltage, or 24 volts. If you have one of the few 110V systems still in use, indicated by wiring nut connections or the back of the thermostat stamped “110V,” then the system isn’t compatible with a WiFi thermostat.

If you have concerns about compatibility, there are two ways to check it:

  • Buy a WiFi thermostat made by your HVAC brand, if one is available. There are many, including the Lennox iComfort, Carrier Côr, Bryant Housewise, Trane ComfortLink II and Heil Observer. Note that these thermostats work with other HVAC brands too. The issue isn’t the brand of the HVAC system or the thermostat. It’s the performance of your system such as single-stage, two-stage or variable, heating only, heating and air conditioning and humidity control.
  • For thermostats not made by HVAC manufacturers, check compatibility on their site. Ecobee, Emerson Sensi and Nest are just a few of the WiFi thermostat makers that have this option. They allow you to determine if their thermostat is compatible with your HVAC system. You can check this simply by looking at the wiring connections on the back of your current thermostat. Go to the manufacturer’s website, find the compatibility checker. Then, select the letters corresponding to the wiring connections. The page will quickly determine compatibility. If you’re installing a system in new construction or tearing out an old system and thermostat, then your HVAC technician can assist you in determining compatibility.

3. Check for a Common Wire

A WiFi thermostat needs continuous power to remain connected, which is not the case with other thermostats. A wire known as a common wire or C-wire must be installed. Look at the “C” connection in or on the back of your thermostat to determine the presence of a common wire. If you don’t have one, there are four options:

  • Install a C-wire. This is a single strand of the same type of copper wiring used to make the other thermostat connections.
  • Replace all the thermostat wiring with new 18/5 5-conductor wire like this from Lowes.
  • Install a Venstar Add-a-Wire adapter ($25-$35 from many retailers). This one requires installation in the furnace or air handler.
  • Choose a WiFi thermostat like the ecobee3 that has a compatible power extender kit (PEK). The kit replaces the common wire ($20-$25).

In our opinion, the cleanest, most future-proof method is to run new 5-conductor wiring. An HVAC technician or electrician can install it or just a common wire for $100 to $200. The price depends on how accessible the current wiring is and the distance it will travel. The Venstar product makes sense when running new wire isn’t cost-effective. However, an electrician or tech will need about 30 minutes to install it for a minimum service fee of $75 or more.

Note: The Nest is one WiFi thermostat that doesn’t require a C-wire. However, its WiFi connectivity will be intermittent without one. Consequently, that will cause problems when attempting to control it remotely.

thermostat on wall

4. Choose a Programmable WiFi Thermostat that Fits your Schedule

Most programmable WiFi thermostats have one of three scheduling functions:

  • 7-day: These thermostats give you the option of quickly programming every day the same. This is a great option for retirees with a regular routine. You can also program each day separately, so they’re a good choice if you work some weekdays but have others off.
  • 5-2: Set one program for weekdays and one for weekends.
  • 5-1-1: Saturday and Sunday are programmed separately.

Others, like the Carrier Côr and Nest use functional descriptions and motion sensors to control temperature. In the case of the Côr, you program Away, Home, Wake, Sleep and Vacation. You set the temperature you want for each function, and the thermostat uses sensors to determine, for example, whether you are home or away and for how long you’re away, at some point switching to Vacation mode if no motion is sensed.

Less important than the schedule is that you use programming. The US Department of Energy suggests that a programmable thermostat will reduce energy use and cost by 10 percent, but only when it is used. In 2009, the government Energy Star program stopped certifying programmable thermostats. They did this not because they don’t save energy but because most were so difficult to program that many people gave up. So they began using them like non-programmable models and losing the potential benefit.

The WiFi thermostat models with top ratings for easy setup and programming include:

  • Honeywell Lyric;
  • Emerson Sensi;
  • Carrier Côr;
  • Bryant Housewise;
  • Nest;
  • Ecobee Smart SI;
  • LUX Geo.

If you have another WiFi thermostat in mind and want reviews that include ease of setup, see what buyers are saying about it at online retail sites.

5. Check Compatibility with Your Home Automation System or Amazon Alexa

The number of WiFi thermostat models that work directly with Alexa continues to grow. Here are the most popular Alexa-compatible WiFi thermostats at this writing:

  • Nest;
  • Ecobee3;
  • Honeywell Lyric T5;
  • Emerson Sensi;
  • Carrier Côr;
  • iDevices.

Many other WiFi thermostat models work with Alexa, Apple HomeKit and/or with a home automation system through hubs. Some of them are Samsung SmartThings, Insteon, Wink Hub 2, Iris Smart Hub, Logitech Harmony Elite and Smart Home. Check the website of the automation equipment manufacturer or the thermostat manufacturer to ensure compatibility and find instructions on setting up the WiFi thermostat on the system.

Buy, Read and Learn

While the ease of use for WiFi thermostats has improved, there is still a learning curve. After you purchase your WiFi thermostat, download the app and read the enclosed literature. Watch demo videos on the manufacturer’s site. Most WiFi thermostats aren’t difficult to use; they’re just unfamiliar and new. You’ll soon master the thermostat, the app and any home automation applications it integrates with.

Other readers would enjoy hearing your experience with a WiFi thermostat, if you’d come back to share what you bought and your opinion of it. And please pass along this information to your followers and friends. They might be looking for tips on how to buy the right WiFi thermostat too.


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