Quick answer: buy an ENERGY STAR certified model so you qualify for Illinois utility rebates. The Google Nest Learning Thermostat (4th gen) is the easiest fit for homes without a C wire, and the ecobee Smart Thermostat Premium comes with a room sensor and handles more heat pump stages. The Sensi Touch 2 is a simpler pick if your system already has a C wire.
Heating is the big energy job in an Illinois home. In the U.S. Energy Information Administration’s 2020 survey, about 78% of Illinois homes (3.84 million) heated mainly with natural gas, and 17% with electricity [1]. A thermostat that turns the heat down while you sleep or are away cuts how long the furnace runs. The Department of Energy says turning your thermostat back 7 to 10 degrees F for 8 hours a day can save as much as 10% a year on heating and cooling [2].
Why it matters in Illinois
- Homes heating mainly with natural gas
- About 78% (2020) [1]
- Homes heating mainly with electricity
- About 17% (2020) [1]
- ComEd smart thermostat rebate
- ENERGY STAR models bought by Dec. 31, 2026; one per account [3]
- Nicor Gas bonus
- Extra $25 with a furnace rebate on the same application (2026) [4]
- DOE setback savings
- Up to 10% a year on heating and cooling [2]
Illinois rebates to check first
- ComEd (electric): ComEd’s 2026 appliance rebate application covers smart thermostats for current residential customers. The thermostat must be ENERGY STAR certified, new, and bought in Illinois (or you must show you paid Illinois sales tax). Buy by December 31, 2026, and apply within 60 days or by February 28, 2027, whichever comes first. Each account gets one smart thermostat rebate per program year. Higher amounts may be available to income-qualified customers [3].
- Nicor Gas: Nicor’s 2026 residential rebate fact sheet includes smart thermostats, with rebates available January 1 to December 31, 2026, a limit of one rebate per account, and a $25 bonus when you apply for a smart thermostat and a furnace on the same application [4].
- Other utilities: Ameren Illinois, Peoples Gas and North Shore Gas customers should check their own utility’s site. We couldn’t confirm current amounts for them from an official page.
How we chose
- ENERGY STAR certified. Every pick appears on ENERGY STAR’s list of certified connected thermostats [5]. ENERGY STAR says certified models are independently certified, based on field data, to deliver energy savings [6]. That certification is also what ComEd requires [3].
- Works with common Illinois systems. We checked each maker’s spec page for gas furnaces, heat pumps and whether a C (common) wire is needed.
- Recall check. We searched the CPSC recall database on November 2, 2026 [11]. We left out a popular model that the maker lists as discontinued.
- We didn’t use maker savings claims. Several makers advertise percentage savings. We used the Department of Energy’s figure instead [2].
Our picks
Best for: Homes without a C wire
Google Nest Learning Thermostat (4th gen)
Google says it's designed to work whether or not your home has a C wire, and it comes with a separate temperature sensor so you can heat for the room you're in. It's ENERGY STAR certified.
- Works with most 24V systems, including gas, electric, oil, forced air, heat pump and radiant [7]
- Up to 3 heating and 3 cooling stages; heat pumps up to 5 heat and 3 cool [7]
- C wire or Nest Power Connector needed in under 1% of cases, per Google [7]
- Nest Temperature Sensor (2nd gen) in the box; works with Google Home and Matter [7]
- Wi-Fi 2.4 GHz and 5 GHz [7]
Safety check: ENERGY STAR certified (model family GA05###) [5]. CPSC recall search found no recall for Nest thermostats; Nest's only recall listed was for Nest Protect alarms in 2014 (checked 2026-11-02).
Watch out: It costs more than the others here. Run Google's compatibility check before buying, especially with zoned or unusual systems.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Two-story homes with hot and cold rooms
ecobee Smart Thermostat Premium
It includes a SmartSensor for a second room and a Power Extender Kit for homes without a C wire. It also monitors indoor air quality and reminds you to change the furnace filter.
- SmartSensor and Power Extender Kit in the box [8]
- Works with most 24VAC equipment; heat pumps 2H/2C plus 2-stage aux heat [8]
- 4 in. color touchscreen [8]
- 3-year limited warranty [8]
Safety check: ENERGY STAR certified (model family EB-STATE6) [5]. CPSC recall search found no ecobee recall (checked 2026-11-02).
Watch out: Installing the Power Extender Kit means working at the furnace control board. Some people will want a pro for that step.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: ecobee features for less
ecobee Smart Thermostat Enhanced
It has the same 4-inch touchscreen and Power Extender Kit as the Premium, with built-in occupancy sensing. Room sensors are sold separately.
- Power Extender Kit included; SmartSensors sold separately [9]
- Heat pumps 2H/2C plus 1-stage aux heat [9]
- Temperature, humidity and radar occupancy sensors [9]
- 3-year limited warranty [9]
Safety check: ENERGY STAR certified (model family EB-STATE6L) [5]. CPSC recall search found no ecobee recall (checked 2026-11-02).
Watch out: It supports one fewer aux heat stage than the Premium. Check your heat pump setup first.
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Basic gas furnace and AC setups
Google Nest Thermostat
A lower-cost Nest that covers the common one-stage furnace and central air setup, with app control and scheduling.
- Works with most 24V systems, including furnaces, air conditioners, boilers and heat pumps [7]
- 1 heat and 1 cool stage, plus a second heat or cool stage [7]
- 2.4 in. color display; Wi-Fi 2.4 and 5 GHz [7]
- Runs on system power with AAA backup batteries [7]
Safety check: ENERGY STAR certified (model family GA0####) [5]. CPSC recall search found no recall for Nest thermostats (checked 2026-11-02).
Watch out: Google says heating-only, cooling-only, zoned and heat pump systems may need a C wire or the Nest Power Connector [7].
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Best for: Homes that already have a C wire
Sensi Touch 2 Smart Thermostat (ST76)
A touchscreen thermostat from Copeland's Sensi line that sets up in the Sensi app and can be configured for air conditioners or heat pumps and their stages.
- Requires a C wire; won't power on without one [10]
- Needs 20 to 30 VAC between RH (or RC) and C [10]
- Connects to 2.4 GHz Wi-Fi only [10]
- App setup for AC or heat pump and number of stages [10]
Safety check: ENERGY STAR certified (ST76) [5]. CPSC recall search found no recall for the Sensi Touch 2. An older SensiWiFi model (1F86U-42WF and UP500W, made 2014 to 2015) was recalled in 2018 for a fire hazard (checked 2026-11-02).
Watch out: No C wire, no install. Sensi says some heat-only systems may be able to use an external transformer instead [10].
See it on Amazon → We chose it from specs and safety records; we haven't tested it ourselves.
Buying guide
- Check your wires first. Take a photo of the wires behind your current thermostat. If there’s no wire on the C terminal, favor a model that works without one or comes with an adapter.
- Know your system. Write down whether you have a gas furnace, boiler, heat pump or dual fuel. Every maker has an online compatibility checker.
- Mind the Wi-Fi. ENERGY STAR says to keep a Wi-Fi thermostat reasonably close to the router to avoid dropouts [6].
- Save your receipt. ComEd asks for a copy of the full sales receipt with the rebate application [3].
- Line-voltage heat is different. These picks are for low-voltage (24V) systems [7][8]. Electric baseboard heat on 120V or 240V needs a different kind of thermostat.
Sources
- U.S. Energy Information Administration: Highlights for space heating fuel in U.S. homes by state, 2020 (RECS)
- U.S. Department of Energy: Home Upgrades
- ComEd: ENERGY STAR Appliance Rebate Application, 2026
- Nicor Gas: Rebates for your home, Jan. 1 to Dec. 31, 2026 (fact sheet)
- ENERGY STAR Product Finder: Certified Connected Thermostats (accessed Nov. 2, 2026)
- ENERGY STAR: Smart Thermostats
- Google Nest Help: Nest thermostat technical specifications
- ecobee: Smart Thermostat Premium
- ecobee: Smart Thermostat Enhanced
- Copeland: Sensi Touch 2 Smart Thermostat Installation Guide
- U.S. Consumer Product Safety Commission: Recalls database (searched Nov. 2, 2026)
Common questions
Does ComEd give a rebate for a smart thermostat in 2026?
Yes, for ComEd residential customers. ComEd's 2026 appliance rebate application covers ENERGY STAR certified smart thermostats bought by December 31, 2026, one per account per program year. Apply within 60 days of purchase or by February 28, 2027, whichever comes first. Check ComEd's site for the current amount.
Does Nicor Gas offer a smart thermostat rebate?
Nicor Gas lists smart thermostats among its residential rebates for January 1 to December 31, 2026, and adds a $25 bonus when you apply for a smart thermostat and a furnace rebate on the same application.
How much can a smart thermostat save?
The U.S. Department of Energy says you can save as much as 10% a year on heating and cooling by turning your thermostat back 7 to 10 degrees F for 8 hours a day. A smart thermostat makes that automatic, but savings depend on your home and habits.