What thermostat settings should you use in winter and summer? Thermostat settings of 68°F to 70°F while awake are DOE’s winter recommendation, with a setback while you sleep or leave. DOE publishes no summer number.
Key Takeaways
- DOE Energy Saver: set it “to around 68°F to 70°F while you’re awake and setting it lower while you’re asleep or away” (archived copy).
- The DOE savings claim is conditional: “as much as 10% a year” for a 7°F to 10°F setback held 8 hours a day.
- The 78°F often quoted for summer is a factory default in 2015 IECC Section R403.1.1, not a DOE comfort figure.
- EIA’s 2020 RECS: 50.69 million of 123.53 million US homes set one heating temperature and leave it there.
- DOE says programmable thermostats are “generally not recommended for heat pumps” unless built to minimize backup resistance heat.
- ENERGY STAR certified smart thermostats save “approximately 8% of heating and cooling bills or $50 per year.”
What thermostat settings does DOE actually recommend?
One number, and it is a winter number. DOE’s Energy Saver guidance says to set the thermostat “to around 68°F to 70°F while you’re awake and setting it lower while you’re asleep or away from home.” For summer it publishes no figure, only a rule: “The smaller the difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be.”
The Energy Saver summer page (archived copy) says only to “set your thermostat at a temperature you find comfortable and that provides humidity control, if needed.” The familiar 78°F comes from DOE’s Building Energy Codes summary of 2015 IECC Section R403.1.1: a shipped programmable thermostat must ship with a cooling set point no lower than 78°F. It is a code default, and it moves a bill less than what cooling costs per kilowatt hour where you live.
What does the 10% setback savings claim actually say?
It says this, in full: “You can save as much as 10% a year on heating and cooling by simply turning your thermostat back 7°-10°F for 8 hours a day from its normal setting.” The conditions: 7°F to 10°F deep, 8 hours a day, and “as much as” is a ceiling.
DOE adds the condition most people drop: “The percentage of savings from setback is greater for buildings in milder climates than for those in more severe climates.” Hours held matter too: “the longer your house remains at the lower temperature, the more energy you save.” A percentage is not a dollar figure, which is why it travels badly into seasonal fuel cost forecasts.
The reheat myth, corrected by DOE
DOE names it: “A common misconception associated with thermostats is that a furnace works harder than normal to warm the space back to a comfortable temperature after the thermostat has been set back, resulting in little or no savings.” The answer follows: “as soon as your house drops below its normal temperature, it will lose energy to the surrounding environment more slowly.”
Which thermostat settings fit occupied, asleep and away?
DOE publishes one set point and one setback depth. The table applies its 7°F to 10°F setback to its 68°F to 70°F baseline and marks what DOE leaves unstated.
| Period | Winter | Summer | Federal basis |
|---|---|---|---|
| Occupied and awake | 68°F to 70°F | No figure published | DOE Energy Saver, stated for winter only |
| Asleep | 58°F to 63°F | No DOE figure | DOE says “lower while you’re asleep”; depth from its 7°F to 10°F figure |
| Away 8 hours or more | 58°F to 63°F | 7°F to 10°F above occupied | DOE savings claim, 7°F to 10°F for 8 hours a day |
| Factory default at shipment | No higher than 70°F | No lower than 78°F | 2015 IECC R403.1.1 |
| Range the control must reach | Down to 55°F | Up to 85°F | 2015 IECC R403.1.1 |
DOE adds a threshold worth copying: “If there is a time during the day when the house is unoccupied for four hours or more, it makes sense to adjust the temperature during those periods.” A summer warning follows: setting the thermostat colder than normal at startup “will not cool your home any faster,” a property of the control covered in our piece on what a thermostat can and cannot sense.
Why do heat pumps break the setback rule?
Because recovery is not free on a heat pump. DOE says it directly: “Programmable thermostats are generally not recommended for heat pumps.” In heating mode, “setting back its thermostat can cause the unit to operate inefficiently, thereby canceling out any savings achieved by lowering the temperature setting. Maintaining a moderate setting is the most cost-effective practice.”
The mechanism is backup heat. A deep setback leaves a large gap at recovery, and the control calls in resistance elements to help the compressor close it. That is the costliest heat the system makes, as explained in auxiliary heat versus emergency heat.
DOE allows an exception: thermostats “specially designed” for heat pumps “typically use special algorithms to minimize the use of backup electric resistance heat systems.” The Building America Solution Center calls this adaptive recovery: the thermostat “senses the temperature difference to be overcome and triggers the heat pump earlier,” closing the gap gradually with the compressor alone.
Code backs the lockout. DOE’s Building Energy Codes summary of 2015 IECC Section R403.1.2 requires controls that “prevent supplementary electric-resistance heat when heat pump can meet the heating load,” with one exception: during defrost.
How do US households actually set their thermostats?
Most pick one number and stop. EIA’s 2020 Residential Energy Consumption Survey, Table HC6.1, reports that 50.69 million of 123.53 million US homes set one heating temperature and leave it there most of the time. Another 31.04 million adjust manually. Only 19.79 million let a programmable or smart thermostat adjust automatically.
Cooling matches. Table HC7.1 puts 45.94 million homes on one fixed cooling setting against 16.60 million on automatic schedules. Hardware is not the constraint: 52.59 million homes had a programmable thermostat and 12.78 million a smart one.
Set points cluster near DOE’s winter figure. The largest winter daytime occupied band is 67°F to 69°F at 32.57 million homes. In summer it is 74°F to 76°F at 27.17 million. One house-wide number hides room by room spread that only zoning or envelope work such as attic insulation depth can close.
Does humidity change the right thermostat setting?
In summer, yes, because a basic thermostat reads temperature only. EPA’s mold and moisture guidance sets the target: “If possible, keep indoor humidity below 60 percent (ideally between 30 and 50 percent) relative humidity.” In winter the problem reverses, and a whole house humidifier still has to respect that 50 percent ideal ceiling.
This is why DOE’s summer wording includes “and that provides humidity control, if needed.” An air conditioner dehumidifies only while the coil runs, so an oversized system that short cycles can leave a house cool and clammy, the failure mode in why a house can be cold and humid at once. Moving air helps at the margin, which is what fan direction by season is for.
What does a smart thermostat change about thermostat settings?
It changes execution, not physics. ENERGY STAR says certified smart thermostats save “approximately 8% of heating and cooling bills or $50 per year” on average, adding: “Savings may be greater depending on climate, personal comfort preferences, occupancy, and/or heating/cooling (HVAC) equipment.”
The certification rests on field data. ENERGY STAR’s energy savings criteria require an annual run time reduction of at least 8% for heating and at least 10% for cooling, each the lower 95% confidence limit of a weighted national average. Under the Version 1.0 field savings method, manufacturers sample 250 installed thermostats in each of five EIA climate zones and measure against what run times “would have been under 24/7 use of baseline comfort temperatures.”
The method also reports, for heat pumps, Resistance Heat Utilization, “the proportion of total heating run time that includes auxiliary and emergency heating,” in 5°F outdoor bins from 0°F to 60°F. A thermostat that saves run time by leaning on strip heat shows up there. It does not change equipment capacity, duct losses, or the difference between a heat pump and an air conditioner. Wiring is the usual obstacle, covered in smart thermostat wiring and compatibility.
How we researched this
Cited: DOE Energy Saver pages, read as Internet Archive copies because the live pages return errors; EIA RECS 2020 Tables HC6.1 and HC7.1 (final release March 2023); the Building America Solution Center; DOE Building Energy Codes on the 2015 IECC; ENERGY STAR criteria and field savings method; EPA moisture guidance. Consulted but not cited: DOE’s fall and winter tips page, which repeats the 10% claim.
Excluded: manufacturer savings claims, utility estimates and contractor set point charts, none of which publish a sample basis. Reddit threads shaped the questions only and supplied no quote or number. Setback temperatures in the schedule table are arithmetic on DOE’s 7°F to 10°F range, labelled as such. Research completed September 2026.
Frequently asked questions
What temperature should I set my thermostat in winter?
DOE says “around 68°F to 70°F while you’re awake and setting it lower while you’re asleep or away from home.” That is the only winter set point it publishes. Its 7°F to 10°F setback depth puts a typical sleep or away setting near 58°F to 63°F.
Is 78°F really the official summer thermostat setting?
Not as a DOE comfort recommendation. It comes from 2015 IECC Section R403.1.1, which requires a programmable thermostat to ship with a cooling set point no lower than 78°F. DOE’s summer guidance gives no number, only a comfortable temperature providing humidity control.
Does turning the heat down and back up cost more than leaving it?
No. DOE calls this a common misconception: “as soon as your house drops below its normal temperature, it will lose energy to the surrounding environment more slowly.” The longer the house sits lower, the less it loses, so the recovery burn stays smaller than the losses avoided.
Should I use a setback schedule on a heat pump?
Only with a thermostat built for it. DOE says programmable thermostats are “generally not recommended for heat pumps” because recovery can call in electric resistance backup and cancel the saving. Adaptive recovery models start the compressor earlier and close the gap gradually.
How much does a smart thermostat actually save?
ENERGY STAR reports approximately 8% of heating and cooling bills, or $50 per year, for certified models on average. Certification requires field data from installed units, sampled at 250 thermostats in each of five EIA climate zones, showing at least 8% heating and 10% cooling run time reduction.
Why does the same thermostat setting feel different in summer?
Because a basic thermostat measures temperature and ignores moisture. EPA advises keeping indoor relative humidity below 60 percent, ideally between 30 and 50 percent. DOE’s summer advice is to pick a comfortable temperature “that provides humidity control, if needed,” so the answer is often drier air, not a colder set point.
Sources
- U.S. Department of Energy, Energy Saver. “Programmable Thermostats.” Archived copy. https://web.archive.org/web/2025id_/https://www.energy.gov/energysaver/programmable-thermostats. Accessed September 2026.
- U.S. Department of Energy, Energy Saver. “Spring and Summer Energy-Saving Tips.” Archived copy. https://web.archive.org/web/2025id_/https://www.energy.gov/energysaver/spring-and-summer-energy-saving-tips. Accessed September 2026.
- U.S. Energy Information Administration. “2020 RECS Table HC6.1: Space heating in U.S. homes, by housing unit type.” https://www.eia.gov/consumption/residential/data/2020/hc/pdf/HC%206.1.pdf. Accessed September 2026.
- U.S. Energy Information Administration. “2020 RECS Table HC7.1: Air conditioning in U.S. homes, by housing unit type.” https://www.eia.gov/consumption/residential/data/2020/hc/pdf/HC%207.1.pdf. Accessed September 2026.
- U.S. Department of Energy, Building America Solution Center. “Thermostat Controls.” https://basc.pnnl.gov/resource-guides/thermostat-controls. Accessed September 2026.
- U.S. Department of Energy, Building Energy Codes Program. “2015 IECC Residential Requirements.” https://www.energycodes.gov/sites/default/files/2019-09/2015_IECC_residential_requirements.pdf. Accessed September 2026.
- ENERGY STAR. “Smart Thermostats FAQs.” https://www.energystar.gov/products/heating_cooling/smart_thermostats/smart_thermostat_faq. Accessed September 2026.
- ENERGY STAR. “Version 1.0 Method to Demonstrate Field Savings of ENERGY STAR Connected Thermostats.” https://www.energystar.gov/sites/default/files/Version%201.0%20Method%20to%20Demonstrate%20Field%20Savings%20of%20ENERGY%20STAR%20Connected%20Thermostats.pdf. Accessed September 2026.
- U.S. Environmental Protection Agency. “A Brief Guide to Mold, Moisture and Your Home.” https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home. Accessed September 2026.
Leave a Reply