Smart Thermostats – Energy Savings, Installation & Buyers Guide

Smart Thermostats – Energy Savings, Installation & Buyers Guide

The market for smart thermostats has exploded in recent years.  Last year analysts pegged the smart thermostat market at $1 billion per year and expect it to grow to over $3 billion per year by 2026.  It’s no surprise, smart thermostats can save you money, improve the comfort of your home and do away with the hassles of programming your thermostat.  Programmable thermostats earned a reputation for their lack of intuitive functionality and were often fodder for late-night talk show jokes with how difficult they were to program.  

That all began to change in 2007 when Stuart Lombad, the founder of ecobee, decided to solve the thermostat programming problem by creating the world’s first smart thermostat. Stuart’s creation ushered in an era of innovation in how we regulate the temperature in our home.  Today, there are over 60 Energy Star certified smart thermostats to choose from ranging in price from $118 to $249.

Here’s what we’ll be covering (feel free to skip around).

  1. What is a smart thermostat?
  2. How do smart thermostats work?
  3. What are the benefits of smart thermostats?
  4. How much do smart thermostats cost and how much will I save?
  5. What is the best smart thermostat to choose?
  6. Checking compatibility with your HVAC
  7. Installing a smart thermostat

What is a smart thermostat?

The true promise of the smart thermostat is a device that requires very little input from you to control the temperature of your house for optimal comfort and energy efficiency.  Today’s most advanced smart thermostats use a combination of technologies and functionality to learn your behavior and preferences (and those of people living with you)  to heat and cool your home only when you need it…and not when you don’t.  All smart thermostats are WiFi-enabled and typically are accompanied by a mobile app that allows you to control your smart thermostat remotely.  Smart thermostats have been so effective that Energy Star has stopped rating programmable thermostats (since most of us never programmed them effectively) in favor of smart thermostats.

In addition, many utility companies offer rebates on qualifying smart thermostats making it a bit more affordable for you to purchase a smart thermostat for your home.  You can use Zwell’s rebate finder to find out if your utility offers a rebate.

How do smart thermostats work?

Some smart thermostats use one or more sensors to detect if your home is occupied and suspend heating or cooling if people are not inside the home.  Using these sensors, smart thermostats also attempt to learn the patterns of people living in your home to create an auto-schedule to maximize your comfort and energy savings.

Yet another technique smart home manufacturers use to detect when people are home is called geofencing.  A smart thermostat using geofencing technology detects the presence of people in the home using GPS and their smartphones.  Similar to how maps on your phone know where you are, a smart thermostat knows if you aren’t home and can set temperatures accordingly as well as learn the behaviors of the people that live in the home.  

What are the benefits of smart thermostats?

The primary benefit of the smart thermostat is still the ability to provide maximum comfort while minimizing wasted heating or cooling of your home when no one is home.  It’s technically possible to achieve similar benefits by using a programmable thermostat, but with costs coming down and rebates from your utility, it’s a great time to check into a smart thermostat for yourself.

Smart thermostats are continuing to get smarter too.  By leveraging WiFi to connect to the Internet, you are able to monitor and control your smart thermostat remotely and receive a variety of system notifications related to your energy usage, HVAC system health and maintenance notifications, benchmarks comparing your energy usage to other smart thermostat users and current weather conditions and forecasts among other features.

How much do smart thermostats cost and how much will I save?

Smart thermostats range in price from $119 to $249 and rebates from utility providers can range anywhere from $25 up to $200.

Several homeowners install smart thermostats themselves, but there are also a variety of qualified professionals willing to install a smart thermostat for your home.  Professional installation prices start as low as $200 and go up depending on your location, your existing HVAC system, and the types of smart thermostat products you wish to install.

There are several factors that go into how much energy you can expect to save by switching to a smart thermostat, including the type of thermostat you are switching from (i.e. manual or programmable), the weather conditions in your area, and your lifestyle and comfort preferences.  Manufacturers and independent 3rd parties have studied the actual energy savings of smart thermostats compared to people using a manual thermostat or a programmable thermostat.  All of the studies we’ve read show some sort of saving.  The typical range seems to fall in the 10% to 15% range, but again your actual results will vary based on the factors identified above.

What is the best smart thermostat to choose?

That gets us to what actually is the best smart thermostat for you and your home.  At Zwell, our smart thermostat recommendations are based on the following criteria in this order of importance:

  1. How well does the smart thermostat do its job?  Remember, for all the bells and whistles built into today’s smart thermostats, their goal is to heat and cool your house to your desired temperature, save you money by not heating or cooling your home when you don’t need it, and to do so with as little input from you as possible.
  2. Next on our list is how easy it is to install, or can you easily find a qualified professional to install it for you.
  3. From installation to support, does the company stand behind its products and make it easy for you to get service should you need it?  In addition, how does the manufacturer’s warranty compare to other manufacturers?
  4. Finally, does the smart thermostat offer any other valuable features that will make your life easier like monitoring the health of your HVAC system?

The top four smart thermostats that best meet our criteria are:

  1. Google’s Nest Learning Thermostat
  2. Google’s Nest Thermostat E.
  3. ecobee’s Smart with Voice Control
  4. Honeywell Home T10 Pro

Again, there are over 60 smart thermostats listed on the Energy Star website and there are some specific to your HVAC system that also may be worth considering.

Checking compatibility with your HVAC

Unless you’ve had to replace or service your HVAC system recently you probably don’t even know when it was built and who manufactured it.  HVAC systems are usually out of sight and out of mind unless there is a problem.  Before you purchase a smart thermostat definitely check to see that the smart thermostat is compatible with your HVAC system.

Below are links to each of the recommended manufacturers’ compatibility tools:




Installing a smart thermostat

Installing a smart thermostat is accessible to most DIYers, but there is also a vast network of professional installers ready to help install a smart thermostat in your home.  The manufacturers of smart thermostats have invested a lot of time and money to produce detailed installation instructions, methods for checking compatibility, mobile app-based setup procedures and there are hundreds of video tutorials to help guide you through the process.

Before we get started with an overview of the basic installation procedures, there are a couple of things to take into consideration based on our experience installing smart thermostats ourselves.  Make sure you keep your old thermostat in case the installation doesn’t go as planned and you need to fall back to what was working before.  Also, you may want to undertake the project during hours when you can get support from the manufacturer you’ve chosen in case any unexpected issues come up that you need to get answers to.  Finally, a smart thermostat is much less expensive than replacing or fixing a broken HVAC system, so make sure you have an HVAC technician or electrician if you get in over your head.

Here’s an overview of the basic steps you’d likely follow if you were installing a new smart thermostat.  You’ll of course want to follow the manufacturer’s specific instructions, but this will give you a rough idea of the type of work involved.

  1. Turn off your HVAC System at the breaker panel
  2. Remove the faceplate of your old thermostat to see the wiring and backplate.
  3. Take a photo of the wiring so you have a way of seeing which lines connect to which terminals should you need it
  4. Remove the backplate of your old thermostat
  5. Optionally you may need to add  a C wire if your old thermostat doesn’t have one
  6. Install the new thermostat backplate according to the manufacturer’s instructions
  7. After you’ve securely attached the backplate and pulled the wire through you are ready to attach the wires
  8. Now that the wiring is in place you should connect the faceplate of your new thermostat onto the backplate
  9. Turn the breaker back on to your HVAC system, which should power up your new smart thermostat
  10. Connect your smart thermostat to the Internet through your WiFi.
  11. Complete the setup of your smart thermostat through the manufacturer’s mobile app and start saving money


Finding the right contractor can be the key to having a smart system installed correctly and safely, and is certainly easier than doing it yourself. Beyond word-of-mouth recommendations, local building inspectors or trade groups may have a list of licensed contractors in your area.

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