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The most reliable gas-saving setup is a comfortable temperature when the house is occupied, followed by a modest setback during sleep or an absence of about eight hours. Schedule recovery before people wake up or return, then adjust the setback using actual comfort and runtime data. There is no federally mandated “best” temperature: the U.S. Department of Energy says Americans should set thermostats to whatever temperature they choose.
DOE’s 2024 Energy Saver guidance says a setback lasting at least eight hours a day can save as much as 10% per year on heating and cooling costs. The saving depends on your weather, insulation, equipment, schedule and how consistently the program runs.
The settings to try first
Use one temperature for occupied periods and a lower temperature for predictable unoccupied periods. Start with a small change rather than an aggressive drop, and keep the setting that preserves sleep and daytime comfort. A practical first experiment is lowering the heating target by a few degrees during an eight-hour sleep or work absence; increase or reduce the change after reviewing comfort and runtime.
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| Period | Recommended approach | Why it helps |
|---|---|---|
| Occupied | Choose the lowest temperature that feels comfortable to the people in the home. | Comfort is the controlling constraint; DOE does not prescribe a universal setpoint. |
| Sleeping | Use a modest setback for the full sleep period. | Longer setbacks give the house more time to lose heat and reduce burner runtime. |
| Work or school absence | Set back while the home is empty, then schedule recovery before arrival. | The system avoids heating an empty house but restores comfort when needed. |
| Short errand | Leave the occupied setting or use only a small change. | A brief absence may not provide enough time for a meaningful saving. |
| Extended travel | Use vacation mode with freeze protection enabled. | Vacation controls can reduce heating while helping protect plumbing from freezing. |
Do not judge a schedule by the thermostat number alone. Compare how long the furnace runs, whether rooms reach the target on time, and whether anyone uses portable heaters or overrides the program. Those observations reveal whether a lower setting is genuinely saving energy in your house.
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Why an eight-hour setback can reduce gas use
A house loses heat faster when the indoor temperature is much higher than the outdoor temperature. Lowering the indoor target reduces that temperature difference for the hours of the setback, so the heating system adds less heat during that period. When the schedule calls for recovery, the furnace runs until the target is reached.
DOE’s Energy Saver guidance associates a setback of at least eight hours per day with savings of up to 10% per year on heating and cooling costs. “Up to” is important: the figure is not a guarantee for every building, climate or fuel bill. A well-insulated home, a drafty home, a mild winter and a severe winter can produce very different results.
Heating and cooling are a major household expense. ENERGY STAR reports that almost half of the average American household’s annual energy bill goes to heating and cooling, exceeding $900. Reducing unnecessary runtime therefore matters, but comfort and safe operation still come first.
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1. Record the household pattern
For several days, note when the last person leaves, when someone returns, when the household goes to bed and when it wakes. Include irregular days such as remote-work days, weekends and school holidays. A schedule based on an assumed routine wastes energy when the house is actually occupied.
2. Set the occupied period
Choose the lowest occupied temperature that feels comfortable to the people who use the rooms. DOE’s position is that occupants may choose any temperature; the energy decision is how long the house remains at that temperature, not compliance with a prescribed number.
3. Add the sleep setback
Create a lower heating target at bedtime and keep it until the planned wake-up period. Start with a modest reduction. If anyone wakes cold, shorten the setback, reduce its depth or improve air distribution before trying a deeper reduction.
Rank #2
- High use of the scheduling feature of the T5 thermostat saved customers between 8 and 16% on heating and cooling bills. Dollar savings range based on nationwide average annual single-family detached home's heat and cooling bills; actual savings varies based on consumption.
- Save Energy and Get Rewarded. Check with your energy provider about available energy savings rebates to save on your purchase. Plus, eligible customers can enroll in their local Utility's "DEMAND RESPONSE PROGRAM" which can reward you for allowing the utility to slightly adjust your AC or furnace temperature settings when there is high energy demand.
- 7-Day Flexible Scheduling or Location Based Temperature Control. It’s your choice. 7-day scheduling programs your thermostat. Geofence technology helps make you comfortable by using your smartphone’s location to know when you’re away and when you return.
- Auto Home and Away Mode. Enjoy ideal temperatures at home, then save when away.
- ENERGY STAR certified. Help save energy, track your heating and cooling with monthly energy reports and get personalized tips on reducing energy use.
4. Add the away setback
Set back after the last departure and schedule recovery before the first expected arrival. Leave enough lead time for your equipment to warm the building; the correct lead time is specific to the home, outdoor weather and heating system.
5. Observe recovery
Check whether the target is reached when the schedule says it should be. If recovery finishes too early, move the recovery time later. If the house is still cold at arrival, move it earlier or use the thermostat’s equipment-specific recovery setting rather than making the setback much deeper.
6. Review data weekly
Use runtime or energy reports to compare similar weeks. Look for reduced heating runtime without more manual overrides, cold-room complaints or auxiliary heaters. Change one schedule element at a time so you can identify what helped.
What a smart thermostat adds
Learning schedules
ENERGY STAR says certified smart thermostats can learn temperature preferences and establish schedules that move to energy-saving temperatures when occupants are asleep or away. Learning is useful when routines change, but review the generated schedule. A device that interprets a short absence as a full away period can make a room uncomfortable.
Geofencing
Geofencing uses phone locations to detect departure and return. It can initiate an away setback and preheat before a person arrives. Confirm whose phones are included, what happens when one person remains home, and whether location permissions or account changes disable the feature.
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Remote sensors can identify a hot or cold room and, on compatible systems, give that room priority during a scheduled period. Place sensors where people actually spend time, not beside a draft, supply register, window or heat-producing appliance. A sensor cannot correct poor insulation or a blocked vent; it only changes which temperature reading controls the system.
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- SAVE ABOUT 23% ON HVAC ENERGY*: The ENERGY STAR-certified Sensi smart thermostat can help you save energy with features like flexible scheduling, remote access and usage reports
- SIMPLE CONFIGURATION: Looks and feels like a thermostat. Has buttons and fits the same space as a traditional thermostat so you don’t have to patch and paint your walls
- SMART MAINTENANCE: Sensi can help monitor the performance and efficiency of your HVAC system by delivering valuable usage reports, alerts about your equipment, and maintenance reminders like filter replacement
Vacation mode
Vacation mode holds a reduced temperature for an extended absence and can maintain a freeze-protection threshold. Set the return date and verify the mode has an end time. A permanent low setting without freeze protection is not an appropriate substitute.
Runtime and energy reports
Reports let you compare heating runtime and comfort over time. Treat them as trend data rather than a gas meter: runtime does not account for every factor affecting fuel consumption, such as burner capacity, outdoor temperature or boiler cycling. Compare periods with similar weather and occupancy whenever possible.
Choosing an ENERGY STAR certified model
ENERGY STAR certification is based on real-world field data. The program requires a schedule function, energy-use feedback, utility-program capability and heating-runtime savings criteria. Its heating criterion requires a lower-95%-confidence weighted national-average annual heating-runtime reduction of at least 8%, and the weighted average of 20th-percentile savings must be at least 4%.
Those are certification benchmarks, not a promise that every household will save 8%. Actual results depend on the building, equipment, settings and behavior. ENERGY STAR estimates that homes with high heating and cooling bills or long daily vacancies can save approximately $100 per year with a certified smart thermostat. A 2023 EPA/ENERGY STAR factsheet projected that universal use could save 56 trillion British thermal units and $740 million annually; that projection is a population estimate, not an individual guarantee.
Check compatibility before buying or installing
Most smart thermostats use low-voltage wiring, and many require a C-wire for reliable power. Models and adapters differ, so inspect the existing thermostat and confirm the equipment documentation before purchasing.
- Identify the system: gas furnace, hot-water boiler, forced-air system, heat pump or another configuration.
- Photograph the wiring: record each terminal label before disconnecting anything. Wire colors are not a reliable substitute for terminal labels.
- Check for a C-wire: determine whether a common wire is present at the thermostat and connected at the control board. If it is absent, verify that the thermostat supports an adapter or another approved power method.
- Confirm control requirements: some boilers and furnaces use special relays, proprietary controls or multiple stages that a generic thermostat may not support.
- Verify voltage: do not connect a low-voltage smart thermostat to a line-voltage heating circuit unless the manufacturer explicitly provides compatible equipment.
- Check local utility programs: rebates and demand-response terms vary by utility and location. Confirm eligibility before assuming a discount.
If you cannot identify the terminals or system type, use qualified installation help. Incorrect wiring can damage controls or leave the heating system inoperable.
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- 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
When a deeper setback can backfire
Do not assume that a larger temperature drop always produces a larger practical saving. DOE smart-thermostat benchmarking research found that higher-efficiency multispeed equipment may maintain comfort efficiently at low capacity, while setback recovery can call for a high-capacity, lower-efficiency mode. A long, deep setback can therefore change how the equipment operates during recovery.
Heat pumps
Heat pumps may use auxiliary or resistance heat during rapid recovery. Follow the manufacturer’s guidance and use the thermostat’s heat-pump recovery settings. Compare runtime, comfort and any auxiliary-heat indication before adopting a large setback.
Modulating or multispeed furnaces
These systems can be designed to run for long periods at low output. A modest, steady adjustment may work better than forcing a rapid recovery at maximum capacity. Use the equipment-specific mode supplied by the thermostat or manufacturer.
Hot-water boilers
Radiators and radiant floors respond slowly. Schedule recovery earlier and avoid judging the program immediately after a setpoint change. Confirm that the thermostat is compatible with the boiler’s control voltage and staging.
Short cycling or overshoot
If the furnace starts and stops repeatedly, the recovery target is reached much too quickly, or temperatures overshoot, inspect the thermostat location, cycle-rate setting and equipment compatibility. A service technician should evaluate persistent short cycling.
Fix comfort problems before abandoning the setback
One room stays cold
- Check that the supply register and return grille are open and unobstructed.
- Move a remote sensor away from drafts, sunlight and heat-producing electronics.
- Inspect filters and ductwork; uneven airflow can make a reasonable whole-home setting feel wrong in one room.
- Use a sensor-based comfort schedule only if the thermostat supports that equipment and control mode.
The house is cold at wake-up or arrival
Move the recovery start earlier in small increments. If recovery triggers high-capacity or auxiliary operation, reduce the setback depth and follow the manufacturer’s recovery guidance.
Best Value
- 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]
The thermostat changes settings unexpectedly
Review learning, geofencing, vacation and hold rules. Check which household phones are enrolled and whether a temporary hold expires at the next schedule period. Disable one automation at a time to find the conflict.
Pipes are at risk during an absence
Use vacation mode with freeze protection, keep interior doors open where appropriate and address known cold spots. A thermostat cannot detect every plumbing risk, especially in unheated crawlspaces or exterior walls.
Maintenance that makes a modest setback easier
ENERGY STAR recommends checking filters monthly during heavy-use periods and replacing them at least every three months. A loaded filter reduces airflow and can lengthen recovery or create hot and cold rooms.
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Arrange annual equipment tune-ups and inspect duct sealing and insulation. ENERGY STAR says duct sealing and insulation can improve HVAC efficiency by as much as 20%. That improvement helps heat reach occupied rooms, reducing the temptation to raise the thermostat because one area feels cold.
How to compare smart thermostats
| Comparison point | Questions to answer |
|---|---|
| HVAC compatibility | Does it control your gas furnace or boiler, stages, relays and wiring, including the C-wire requirement? |
| Scheduling | Can it create separate sleep, away, weekend and vacation periods? |
| Automation | Does it offer learning, geofencing and occupancy sensors, and can each feature be disabled? |
| Recovery behavior | Does it provide settings appropriate for your furnace, boiler or heat pump? |
| Reporting | Can you see runtime and compare periods without treating estimates as gas-meter readings? |
| Utility participation | Is it eligible for your utility’s rebate or demand-response program, and what control rights does enrollment grant? |
| Privacy and accounts | What account, location and occupancy data are required, and can the thermostat operate locally if internet service fails? |
| Installation | Can you identify the wiring safely, or will professional installation be needed? |
| Total cost | What is the purchase and installation cost after a verified local rebate? |
A practical 30-day adjustment plan
- Days 1–3: run your normal occupied setting and note comfort, runtime and room temperatures.
- Days 4–10: add a modest sleep setback lasting the full overnight period.
- Days 11–17: add an away setback that ends before the expected return.
- Days 18–24: test geofencing or learning, but keep a manual schedule available.
- Days 25–30: compare similar-weather days, count overrides and review complaints about cold rooms or late recovery.
Keep the schedule only if it lowers unnecessary runtime without creating uncomfortable rooms, excessive recovery operation or unsafe conditions. The best setting is the one your household follows consistently and your equipment can recover efficiently.
Quick Recap
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