The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Which smart-home devices actually save energy? The ones that change when a significant load runs: a thermostat that makes useful temperature setbacks, occupancy controls that switch off lights in empty rooms, or a plug that cuts standby power from equipment that would otherwise stay on. A connected device by itself is not a saving. Results depend on the equipment it controls, the settings you use, your household routine, and whether the system is compatible with the home.
This guide separates controls from larger equipment upgrades, explains where savings are plausible, and gives a practical way to choose and commission devices in a U.S. home or construction project.
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How smart controls turn into energy savings
Energy savings come from reducing unnecessary runtime, reducing the temperature difference a heating or cooling system must maintain, or replacing an inefficient operating mode. The internet connection, app, voice assistant, and automation are only the means of changing behavior or equipment operation.
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- Occupancy response: A sensor detects an empty room and turns lighting or another load down or off.
- Standby control: A switch disconnects equipment that draws power while idle.
- Feedback: A monitor identifies a large or unusual load so the household can take action.
- Equipment efficiency: A replacement appliance uses less energy to provide the same service; this is different from adding a smart feature.
If none of these mechanisms changes actual use, a device can add convenience without reducing the utility bill. A small load, a routine you already perform manually, or an automation that is disabled after installation has little practical effect.
#1 Best Overall
- ENERGY STAR certified smart thermostat for home that helps you save energy and stay comfortable.Connectivity : Wi-Fi - 802.11b/g/n 2.4 GHz, 802.11a/n 5 GHz Wi-Fi., Wireless interconnect : Bluetooth Low Energy Please refer to the product description section below for all applicable legal disclaimers.Product note: You can also check your system’s compatibility before purchasing a Nest thermostat with our online Nest Compatibility Checker on the Google Nest support page
- The Nest Thermostat is designed to work without a C wire in most homes, but for some systems, including heating only, cooling only, zone controlled, and heat pump systems, you’ll need a C wire or other compatible power accessory
- Nest Thermostat turns itself down when you leave, so you don’t waste energy heating or cooling an empty home. Lock feature: No
- Programmable thermostat that lets you create an energy efficient schedule in the Google Home app on your Android or iPhone
- Remote control lets family members change the thermostat temperature from anywhere on a phone, laptop, or tablet[1]
Smart thermostats: usually the strongest direct opportunity
What they do
Programmable thermostats adjust the set point on a timetable. Smart models may also use occupancy or activity information to adapt that timetable. The saving mechanism is straightforward: avoid heating or cooling an empty home, and use a less demanding set point while people sleep or are away. The U.S. Department of Energy explains the basic operation in its HVAC Programmable Thermostats guidance.
What the 10% figure means
DOE’s 2022 Energy Saver guide says: “You can save as much as 10% per year on heating and cooling by turning your thermostat down 7°–10°F for 8 hours a day in the fall and winter; turn it up in the spring and summer.” This is a conditional estimate for carrying out that setback practice. It is not a guaranteed result from buying any particular smart thermostat, and it does not predict savings for every climate, HVAC system, electricity or fuel rate, or household.
Commissioning checklist
- Identify the HVAC system. Confirm whether the home has conventional furnace-and-air-conditioning equipment, a heat pump, dual fuel, hydronic heat, radiant equipment, or another configuration. Check the thermostat’s compatibility documentation before purchase.
- Verify wiring and power. Some installations need a common wire, an adapter, or professional work. Do not assume that a thermostat that fits the wall opening can safely control the equipment.
- Program realistic setbacks. Start with periods when the home is reliably empty or occupants are asleep. A schedule that constantly conflicts with real life will be overridden and deliver no repeatable saving.
- Use sensors carefully. Place remote temperature or occupancy sensors where they represent occupied spaces, not in direct sun, drafts, kitchens, or behind furniture.
- Check recovery behavior. Heat pumps and some hydronic systems may need different timing than a gas furnace. Avoid settings that trigger inefficient auxiliary heat or uncomfortable catch-up cycles.
- Review results. Compare weather-normalized energy use or utility bills over comparable periods. A single mild or severe month cannot establish a product result.
Where a smart thermostat may disappoint
- The HVAC equipment is incompatible or wired incorrectly.
- The household is home at varying times and repeatedly cancels the schedule.
- The system already has an effective setback routine, so automation adds little.
- Occupancy algorithms misread pets, guests, or an unusual work schedule.
- Connected features create privacy or cybersecurity concerns that outweigh convenience.
DOE identifies data standardization, data accessibility, privacy, and cybersecurity as barriers in connected-thermostat use cases. Review what information is collected, how long it is retained, who can access it, and whether the device remains usable if cloud service or an account is unavailable. See Connected Thermostats Offer Gateway for Increasing Energy Savings.
Lighting controls: savings depend on runtime
Occupancy sensors and timers
Lighting controls work when they shorten the time lights remain on in unoccupied areas. DOE’s Home Energy Checklist points to timers, photocells, and occupancy sensors for this purpose. They are most useful in garages, utility rooms, bathrooms, corridors, storage areas, and exterior lighting that is often left on accidentally.
Rank #2
- An Alexa thermostat - Amazon Smart Thermostat is an easy way to switch from a traditional thermostats for homes and help reduce energy usage.
- Create comfort zones throughout your home by connecting to select Alexa devices to automatically adjust heating and cooling based on temperature readings or presence detection.
- Save money and energy - After purchase, Amazon will send you an email with details about home thermostat rebates that may be available from energy providers in your area.
- Save energy - According to EPA estimates, ENERGY STAR certified thermostats save an average of $90 on yearly energy bills.
- Programmable thermostat and automatic control - Create your own home, away and sleep schedules, or have Alexa automatically control the temperature with Alexa+ advanced features.
Choose the control to match the space
| Situation | Control that fits | Important limitation |
|---|---|---|
| Regular daily schedule | Timer or scheduled switch | Fails when occupancy differs from the timetable |
| Short, unpredictable visits | Occupancy or vacancy sensor | Needs correct sensitivity, timeout, and field of view |
| Outdoor lighting tied to daylight | Photocell, astronomical schedule, or both | Placement and seasonal settings affect operation |
| Frequently used task lighting | Dimming and scene control | Savings depend on using lower output, not merely installing the dimmer |
DOE separately notes that newer lighting technologies can reduce household lighting energy use by 50% to 75% in general. That statement concerns efficient lighting technology, not a promise that smart controls alone produce the same reduction; a control can only reduce the hours or output of the lights it governs. See Why Energy Efficiency Matters.
Construction and retrofit checks
- Confirm the switch is rated for the lamp type, total wattage, and any required neutral wire.
- Check whether low-voltage, three-way, multi-way, or shared-neutral wiring needs a specific device or electrician.
- Set vacancy mode in rooms where an unexpected shutoff would be unsafe or disruptive.
- Use a manual override that does not defeat the automatic schedule permanently.
Smart plugs and power strips: target idle loads, not everything
A smart plug or power strip can cut power to devices that consume electricity while apparently off: entertainment equipment, office peripherals, chargers, or certain appliances. The saving is meaningful only when the controlled equipment has a measurable standby or idle draw and the automation changes its operation. A plug on a tiny load, or on equipment already switched off at the wall, will have little effect.
How to select a useful load
- List equipment that remains energized for convenience, network access, clocks, or remote start.
- Measure its idle draw with a plug-in meter where practical, or use a home energy monitor.
- Check the plug or strip’s voltage, current, motor, heater, and surge ratings before connecting the load.
- Automate a safe off period, such as office equipment after working hours, while preserving required ventilation, refrigeration, medical operation, or network functions.
- Confirm that the device restarts correctly after power is removed; some electronics lose settings or fail to resume.
Do not place high-wattage heaters, large motors, or other demanding equipment on a device unless its listing and installation instructions explicitly permit that use. If a load must remain available for safety or reliability, convenience automation is not an energy-saving priority.
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Home energy monitors: visibility is not a saving
Monitors can display whole-home consumption, circuit-level demand, or selected appliance data. Their value is diagnostic: they help a household discover a water heater that runs unusually often, an electric resistance load, a dehumidifier that never cycles off, or a peak-time pattern that can be changed. The monitor itself does not reduce consumption.
Rank #3
- Save up to 23% every year on heating and cooling costs, adjusts to your set schedule to save energy when you’re gone and optimize comfort when you’re home. Compared to a hold of 72
- Compatible with 85% of systems, check your system’s compatibility with our online ecobee Compatibility Checker on the ecobee support page
- Change your temperature by easily tapping the color touchscreen or using the ecobee app. Plus, free software upgrades ensure you get the best out of your Smart Thermostat Essential, for years to come
- Automatically adjusts to your set schedule to save energy when you’re gone and optimize comfort when you’re home. Keep track of your energy consumption when you're on the go on the ecobee app
- Easy DIY install. No C Wire, no problem. Get the ecobee Power Extender Kit (PEK) for homes without a C-Wire and keep your walls looking nice with our trim kit – both sold separately
Questions to ask before installing one
- Does it read the main service, individual circuits, or only plug-in devices?
- Is the electrical-panel installation permitted for the panel type and local code, and does it require a qualified electrician?
- Are readings close enough to support decisions, and can data be exported without a continuing cloud account?
- Can the household identify a specific action from the display, such as changing a schedule or repairing a failing appliance?
- What data is collected, and how are account access and remote updates secured?
The DOE-hosted presentation Getting Smarter Every Day: Leveraging Smart Home Technologies to Advance Home Performance Projects, credited to CLEAResult, presents category and bundle estimates. Its slide shows an estimated smart-home bundle range of approximately 1,760–2,150 kWh and approximately 80 therms. Those are bundle estimates, not a forecast for a particular home or a guarantee for every product in a category. Climate, equipment, occupancy, controls, and fuel mix can produce very different results.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Water-heater controls versus a heat-pump water heater
Controls on an existing water heater
Connected controls can schedule operation, change modes, or adjust temperature on compatible equipment. DOE’s Federal Energy Management Program says heat-pump water heaters, especially IoT-enabled and smart units, can provide controls and interface modules that let users toggle the unit, switch modes, and change temperatures. The guidance, updated May 2024, is available in Purchasing Energy-Efficient Residential Water Heaters.
Any schedule must preserve safe hot-water operation and household availability. DOE notes that an efficiency mode can lengthen recovery time and reduce first-hour rating. In a remodel, coordinate control wiring, condensate drainage, clearances, electrical capacity, and service access with the installer rather than treating the water heater as an ordinary plug-in device.
The appliance upgrade is a separate decision
A heat-pump water heater is not merely a smart control; it is a different, more efficient way to heat water. In an April 30, 2024 announcement, DOE estimated approximately $1,800 in average lifetime utility-bill savings when replacing a common-sized traditional electric-resistance storage model with a qualifying heat-pump model. That estimate applies to the stated replacement comparison, not to every home or to adding connectivity to an existing heater. Read the context in DOE Finalizes Efficiency Standards for Water Heaters to Save Americans Over $7 Billion on Household Utility Bills Annually.
Rank #4
- COMMON WIRE REQUIREMENTS: Designed to work without a C-wire in most homes, but for some systems, including heating only, cooling only, and heat pump systems, you’ll need a C-wire or other compatible power accessory
- EASY DIY INSTALLATION: Do it yourself fast with a built-in level and simple step-by-step instructions. Works with the HVAC equipment found in most homes
- SAVE ABOUT 23% ON HVAC ENERGY: ENERGY STAR-certified and packed with features that help you save money, including flexible scheduling, geofencing, remote access and usage reports
- PRIVACY PROTECTION: Sensi won’t sell your personal information to third parties or leverage your thermostat activity data for targeting or advertising purposes
- CONTROL FROM ANYWHERE: The top-rated mobile app for Android and iOS devices makes it easy to control your comfort from a smartphone or tablet
For a project, compare hot-water demand, available space and airflow, noise location, condensate disposal, electrical service, climate, operating mode, and local installation requirements. Verify current incentives locally; the cited figures do not establish a current rebate or installed cost.
Comparing device categories before you buy
| Category | What can create savings | What to verify | Why it may not work |
|---|---|---|---|
| Smart thermostat | Temperature setbacks during sleep or vacancy; occupancy response | HVAC compatibility, wiring, schedules, sensors, privacy | Overrides, poor configuration, incompatible equipment, inefficient recovery |
| Occupancy lighting control | Shorter lighting runtime in empty rooms | Wiring, lamp compatibility, sensor placement and timeout | Lights are rarely used, false triggers, or occupants disable it |
| Smart plug or power strip | Disconnects meaningful standby or idle loads | Load rating, restart behavior, safe off periods | Load is tiny, already switched off, or must stay energized |
| Home energy monitor | Reveals a large load that occupants then change | Panel and circuit coverage, data access, installation safety | Information is ignored or too vague to guide action |
| Water-heater control | Schedules or changes modes on compatible equipment | Recovery time, first-hour rating, safe temperature, service conditions | Demand does not match the schedule or comfort suffers |
| Heat-pump water heater | Higher appliance efficiency than electric resistance | Space, condensate, airflow, electrical capacity, operating mode | Installation constraints or unsuitable demand profile |
A practical installation and verification plan
- Start with the load. Identify the largest controllable uses and when they run. Do not begin with a gadget category.
- Establish a baseline. Keep recent bills and, if possible, interval or circuit data. Record occupancy, weather, and unusual events.
- Check compatibility and code. Review manufacturer requirements, panel capacity, HVAC terminals, neutral conductors, ratings, permits, and any need for a licensed electrician or HVAC technician.
- Install one meaningful control first. A single thermostat schedule, high-use lighting zone, or measurable standby load makes the effect easier to evaluate than a house-wide bundle installed at once.
- Commission every setting. Set schedules, sensor locations, timeout periods, temperature limits, notifications, and manual overrides. Document the settings for the homeowner and service team.
- Test normal and abnormal cases. Check a vacant room, a guest arrival, a Wi-Fi outage, a power restoration, seasonal changeover, and a manual override. Confirm that safety-critical equipment remains available.
- Review after a representative period. Compare similar weather and occupancy periods. If use did not change, inspect settings and the controlled load before buying more devices.
Privacy, cybersecurity, and long-term ownership
Connected controls can expose occupancy patterns, temperature history, electrical use, and equipment status. Before enrollment, read the provider’s data practices and account-recovery options. Use unique credentials, multifactor authentication where available, current firmware, and a separate network for smart devices when appropriate. Give the homeowner a local manual control and written instructions for operating the system if the internet, app, or vendor service is unavailable.
For construction handover, record model numbers, wiring changes, sensor locations, default schedules, administrator ownership, and reset procedures. A device that cannot be transferred cleanly to the homeowner may be discarded or left unconfigured, eliminating its intended benefit.
What works—and what does not
The best candidates are controls attached to a substantial load with predictable waste: a thermostat that creates a real setback, a sensor that turns off lights in an empty area, or a switch that disconnects equipment with measurable standby demand. A monitor is worthwhile when someone will use its information to change a load.
Expect little benefit when the device controls a negligible load, duplicates a habit already performed consistently, is incompatible with the installed system, or is left on default settings. Category-level estimates should guide where to investigate, not serve as a promised payback. In every case, measure the controlled use and verify that the automation works in the way the household actually lives.
Quick Recap
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