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If you want the fastest payback, start cheap. The Sensi ST55 costs under $90, needs no C-wire, and delivers the same ENERGY STAR savings as thermostats twice its price. At this price the math works quickly: a year or two of energy savings can cover the purchase, and any utility rebate shortens that further.


Emerson Sensi Wi-Fi Smart Thermostat for Smart Home, DIY, Works With Alexa, Energy Star Certified, ST55

Best Value Pick

If "worth it" means comfort and convenience as much as savings, the ecobee earns its price. The included room sensor evens out hot and cold rooms, built-in Alexa adds a speaker, and ecobee estimates up to 23% in annual heating and cooling savings for homes replacing wasteful habits. It takes longer to pay back than a budget model, but you get more for the money.


ecobee SmartThermostat with Voice Control - Programmable Wifi Thermostat - Works with Siri, Alexa, Google Assistant

Best If You Want More

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At under $60, the Amazon Smart Thermostat is the cheapest way into a genuinely good smart thermostat. It's built on Honeywell Home technology, ENERGY STAR certified (the EPA estimates about $50 a year in savings), and controlled entirely through the Alexa app, which can program schedules for you automatically. The one catch: it needs a C-wire, so if your home lacks one you'll want the bundle that includes an adapter or a battery-powered model instead.


Amazon Smart Thermostat – Save money and energy - Works with Alexa and Ring - C-wire required

Best Cheapest Overall

The Sensi ST55 is the smartest budget buy for most homes because it sidesteps the most common install problem: it runs on two AA batteries, so a common wire is not required in most applications. It's ENERGY STAR certified, works with Alexa, installs in minutes with a built-in level, and carries a 4.5-star average across more than 19,000 Amazon ratings. For older, two-wire homes especially, nothing else at this price is this painless.


Best Value (No C-Wire Needed)

If you can stretch past the $100 mark, the Google Nest Thermostat brings premium polish to the budget tier. You get the clean Google Home app, away detection, energy history, and a soft-touch design that looks far pricier than it is. It usually includes a trim plate to hide marks from your old thermostat. Check compatibility first — it's the budget pick most likely to need a C-wire.


Google Nest Thermostat - Smart Thermostat for Home - Programmable Wifi Thermostat & Trim Kit

Best Budget Splurge

This is the same excellent Amazon Smart Thermostat, bundled with the C-Wire Power Adapter it needs for homes without a common wire. Spending the extra over the bare thermostat buys you a complete, no-surprises install in one box — the adapter, the thermostat, and the same ENERGY STAR savings and Alexa control. It's the budget answer when you want a hardwired thermostat but don't have a C-wire.


Amazon Smart Thermostat with C-Wire Adapter (Made with Honeywell Home Technology, Works with Alexa)

Best Budget for No-C-Wire Homes

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The ecobee SmartThermostat with Voice Control is the most complete package in the category. It ships with a remote SmartSensor so it can balance the temperature in the rooms you actually use instead of just the hallway it's mounted in, it has Alexa built in so it doubles as a smart speaker, and it works with Siri, Google Assistant, and SmartThings alike. Crucially for older homes, it includes ecobee's Power Extender Kit, so it can run without a dedicated C-wire on most 24-volt systems. ecobee estimates savings of up to 23% a year on heating and cooling.


ecobee SmartThermostat with Voice Control - Programmable Wifi Thermostat - Works with Siri, Alexa, Google Assistant - Smart Thermostat for Home

Best Overall

The Google Nest Thermostat is the easiest smart thermostat to recommend to most households. It's ENERGY STAR certified, controlled entirely from the Google Home app, and uses a soft-touch side strip instead of the original Nest's spinning dial. It automatically eases off when you leave so you're not conditioning an empty house, and it usually includes the trim plate that hides marks left by your old thermostat. Just confirm your system's compatibility first, since this is the one Nest model most likely to want a C-wire.


Best Value

The Nest Learning Thermostat is the model that made "smart thermostat" a household phrase, and it remains the most hands-off option. It watches how you adjust the temperature for the first week or two and then builds a schedule for you automatically, so you can largely forget it's there. The polished metal ring and Farsight display that lights up as you walk by still look the part on a wall, and HVAC monitoring flags problems with your furnace or AC before they become emergencies.


Google Nest Learning Thermostat - Smart Wi-Fi Thermostat - Polished Steel

Best Premium

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ecobee is the heat-pump enthusiast's favorite for one big reason: control. It handles multi-stage heat pumps with auxiliary heat and lets you set an auxiliary-heat lockout by outdoor temperature, so your expensive backup strips don't kick on when the heat pump alone could do the job. Add in the included room sensor, built-in Alexa, HomeKit support, and the Power Extender Kit for C-wire-free installs, and it's the most capable heat-pump thermostat for most homes.


Best Overall for Heat Pumps

If you'd rather not micromanage settings, the Nest Learning Thermostat supports heat pumps with auxiliary and emergency heat and manages the switchover automatically once configured. It learns your schedule, looks superb, and includes HVAC monitoring. Note that complex multi-stage heat-pump setups can require careful configuration (sometimes a Nest Pro), so it's the pick for people who want "just keep the house warm" over granular control.


Best Hands-Off for Heat Pumps

The Honeywell Home X7S explicitly supports up to 3 heat / 2 cool heat-pump systems with electric backup, which covers the vast majority of residential heat pumps. You also get a large 4.3-inch touchscreen, humidity monitoring, occupancy sensing, and Matter certification for Alexa, Google, and Apple Home — plus a free C-wire adapter by mail if you need one. It does not work with electric baseboard heat, so confirm your system type first.


Honeywell Home X7S Smart Programmable Wi-Fi Thermostat with Humidity Monitoring, 4.3-inch Touchscreen, Matter, Works with Alexa, Apple, Google

Best Value for Heat Pumps

The Sensi Touch 2 pairs a clean color touchscreen with solid heat-pump support, including auxiliary heat, and it bundles a room sensor to balance temperatures across the house. It's ENERGY STAR certified, supports flexible scheduling and remote access, and Emerson's privacy stance means it won't sell your data. The trade-off versus the Sensi ST55 is that the Touch 2 requires a C-wire for its always-on screen.


Sensi Touch 2 Smart Thermostat & Sensi Room Sensor (Emerson)

Best Touchscreen Value

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The Sensi ST55 is the no-C-wire champion, full stop. Emerson explicitly states a common wire is "not required in most applications," because the thermostat can run on two AA batteries — so for a huge number of older, two-wire homes you simply mount it and go, with nothing to convert and no walls to patch. It's ENERGY STAR certified, works with Alexa, installs with a built-in level and app guidance, and at well under $100 it's also the cheapest pick here. With a 4.5-star average across more than 19,000 Amazon ratings, it's a proven, low-risk choice.


Best Overall — No C-Wire Needed

If you want a flagship thermostat without a wiring project, the ecobee solves the C-wire problem in the box. Every ecobee SmartThermostat (except the Essential and Lite) includes a Power Extender Kit that installs at your furnace and creates a C-wire from your existing wires — no new cable run required. In return you get a remote SmartSensor for whole-home balancing, Alexa built in, and support for Siri, Google, and HomeKit. Note the PEK needs at least four wires and won't work on heat-only or dual-transformer systems.


Best Premium — C-Wire Kit Included

The Honeywell Home X7S is the nicest screen in this group — a customizable 4.3-inch color touchscreen with humidity monitoring and occupancy sensing — and it's Matter certified, so it plays nicely with Alexa, Google, and Apple Home. It does require a C-wire, but Honeywell includes a voucher to claim a C-Wire Adapter by mail at no extra cost, so homes without one are covered. One thing to check first: it does not support electric baseboard (120–240V) heat.


Best Touchscreen — Free Adapter Included

The Amazon Smart Thermostat needs a C-wire — but this bundle simply includes the C-Wire Power Adapter, so you get everything required for a no-C-wire home in one box. It's built on Honeywell Home technology, ENERGY STAR certified (the EPA estimates about $50 a year in savings), and controlled through the Alexa app, which can program it for you automatically. For an Alexa household that wants the cheapest complete solution, this is hard to beat.


Best Budget All-in-One

The Google Nest Thermostat can work without a C-wire on some systems, but it's the most particular model here — without one, certain setups throw "no power" errors or won't charge reliably. We include it because it's affordable, attractive, and superb if your wiring cooperates, but run Google's compatibility checker before you buy. If your system is on the fence, the Sensi or ecobee above are the safer no-C-wire bets.


Most Popular (Check Compatibility First)

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The Sensi ST55 gives you every feature that matters — scheduling, remote control, usage reports, and Alexa support — with no monthly fee, ever. It's ENERGY STAR certified, runs on AA batteries so it needs no C-wire in most homes, and Emerson's privacy policy means it won't sell your data. With a 4.5-star average across 19,000-plus reviews and a price under $90, it's the no-subscription pick we'd hand to almost anyone.


Best No-Subscription Overall

At under $60, the Amazon Smart Thermostat delivers free scheduling and app control through Alexa with no subscription attached. It's built on Honeywell Home technology and ENERGY STAR certified (the EPA estimates about $50 a year in savings). It needs a C-wire, so check your wiring first — but if you have one, nothing this capable costs less to buy or own.


Cheapest With No Fees

All of ecobee's core comfort and savings features are free — the only paid plan is the optional ecobee Smart Security monitoring service, which you never have to enable. Buy it and you get a room sensor, built-in Alexa, HomeKit support, and the Power Extender Kit for C-wire-free installs, all with no mandatory ongoing cost.


Best Premium With No Required Fees

The Google Nest Thermostat gives you scheduling, away detection, and energy history through the free Google Home app, with no subscription required for everyday use. It looks great, installs easily, and is ENERGY STAR certified. Check compatibility first, as it's the most likely here to need a C-wire.


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The Nest Learning Thermostat is the model that defined the category, and it remains the most effortless smart thermostat you can buy. It watches how you adjust the temperature for a week or two, then builds a schedule automatically — after which you can largely forget it exists. The polished metal ring, high-resolution display, and walk-up Farsight feature still look the part on any wall, and built-in HVAC monitoring flags furnace or AC issues early. It's compatible with around 95% of heating and cooling systems.


The Nest Learning Thermostat

The Nest Learning Thermostat only reads the temperature where it's mounted, which is the one real gap versus ecobee. The Nest Temperature Sensor closes it: drop it in a bedroom, nursery, or office and tell the thermostat to prioritize that room at certain times. The battery lasts up to three years, and you can run up to six sensors. If your home has hot and cold spots, budget for at least one of these alongside the thermostat.


Google Nest Temperature Sensor (2nd Gen) - Room Comfort Sensor - Works with Nest Learning Thermostat (3rd and 4th Gen)

Best Add-On

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ecobee's flagship is the most feature-complete thermostat you can buy. It includes a remote SmartSensor for whole-home temperature balancing, has Alexa built in so it doubles as a smart speaker, and supports Apple HomeKit, Siri, Google Assistant, and SmartThings. The included Power Extender Kit means it installs without a dedicated C-wire on most systems. If you want maximum capability and the widest ecosystem support, this is the one.


Best for Features

The Nest Learning Thermostat is the most effortless option in the category. It studies how you adjust the temperature for a week or two and then programs itself, so you can forget it's there. The polished metal ring and walk-up Farsight display are still the best-looking in the business, and built-in HVAC monitoring warns you about furnace or AC trouble early. The trade-off is no built-in room sensor and tighter ties to the Google ecosystem.


Best Hands-Off

If the Learning Thermostat is more than you need, the standard Nest Thermostat delivers the core Nest experience for around half the price. You still get app control through Google Home, away detection, energy history, and a clean soft-touch design — it simply drops the self-learning and the metal finish. Just confirm compatibility first, since it's the Nest most likely to want a C-wire.


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If you have no C-wire but at least four wires at the thermostat, ecobee's Power Extender Kit is the cleanest fix. It installs at your furnace control board and creates a common wire from your existing wiring — no new cable run. It comes free with most ecobee thermostats, but you can buy it separately for around $25. Note: it works with 24-volt systems only, not heat-only, dual-transformer, or high-voltage setups.


ecobee Power Extender Kit C-Wire Adapter - Programmable WiFi Thermostat Accessory

Best C-Wire Adapter

Don't want to deal with a C-wire at all? The Sensi ST55 runs on two AA batteries, so Emerson states a common wire is not required in most applications. For older two-wire homes it's the simplest possible answer — mount it and go, no adapter and no furnace trip. It's ENERGY STAR certified, works with Alexa, and carries a 4.5-star average across 19,000-plus reviews.


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ecobee is the room-sensing leader because it includes a SmartSensor in the box and reads both temperature and occupancy — so the system can prioritize rooms that are actually occupied. Add more sensors as needed to even out the whole house. Combined with built-in Alexa and HomeKit support, it's the most complete answer to hot and cold rooms.


ecobee SmartThermostat with Voice Control - Programmable Wifi Thermostat - Works with Siri, Alexa, Google Assistant (SmartSensor included)

Best for Room Sensing

If you have (or want) a Nest Learning Thermostat, the Nest Temperature Sensor is the way to fix hot and cold spots. Place it in a bedroom, nursery, or office and tell the thermostat to prioritize that room at certain times. The battery lasts up to three years and you can run up to six sensors around the house. It's the simple, inexpensive comfort upgrade for Nest owners.


Best Add-On Sensor

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The Sensi ST55 is the ideal renter's thermostat: it needs no C-wire (it runs on batteries), fits the same footprint as a standard thermostat so it won't leave marks, and is easy to swap back when you move out. It's affordable, works with Alexa, and you can take it to your next place. For apartments, that combination of low cost and zero-modification install is hard to beat.


Best for Renters

If your apartment already has a C-wire, the under-$60 Amazon Smart Thermostat is the cheapest easy upgrade. It's compact, ENERGY STAR certified, and controlled through the Alexa app. Keep your original thermostat in a drawer so you can reinstall it before moving out — a smart move for any renter.


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The Nest Learning Thermostat watches how you adjust the temperature for about a week, then builds a schedule on its own so you stop heating an empty house. Home/Away Assist eases back when everyone leaves, and you can change the temperature from your phone, laptop, or a voice command through Alexa or Google Assistant. The polished metal finish and bright display make it the one most people are happy to mount on a visible wall.


Google Nest Learning Thermostat (3rd Generation)

The standard Nest Thermostat drops the self-learning feature of its pricier sibling but keeps the parts that matter most: a clean app, phone and voice control, and a simple weekly schedule you set once. It can ease the temperature back on its own while you're out, and it's ENERGY STAR certified. For a first smart thermostat, this is the easiest and most affordable way in.


Google Nest Thermostat (Snow)

The Sensi is built to work with the wiring most U.S. and Canadian homes already have, so many people install it in under half an hour without adding a C-wire. From the app you can set flexible schedules, adjust the temperature from anywhere, and check your usage history. It pairs with Apple HomeKit, Amazon Alexa, and Google Assistant, making it an easy fit for an existing smart home.


Emerson Sensi Wi-Fi Smart Thermostat (ST55)

Best for DIY Install

Honeywell's color touchscreen thermostat is the pick if you like setting things by hand on a clear, full-color display. You can build a 7-day program, adjust the background color to suit your wall, and control everything remotely from a phone, tablet, or computer. It's ENERGY STAR certified and works with a wide range of heating and cooling systems.


Honeywell Home RTH9585WF Wi-Fi Smart Color Thermostat

Best Touchscreen

ecobee's entry-level smart thermostat follows your schedule to ease back heating and cooling when you're away and bring the house to comfort before you return. You control it from the color touchscreen or the app, and you can add ecobee SmartSensors later to balance the temperature in the rooms you use most. It works with Apple HomeKit, Alexa, and Google Assistant and installs yourself, even on homes without a C-wire.


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