What temperature should you set your thermostat to?

What temperature should you set your thermostat to in winter?

68°F is the Department of Energy recommendation for waking hours when the home is occupied. That number is calibrated for a typical 35 to 65 year old adult wearing a sweater. Most people find it acceptable. Some find it cold, some find it too warm, and most of the variance comes from what you are wearing and how much you are moving around. A few degrees higher (70 to 72°F) is the realistic comfort zone for households where someone wears a t-shirt indoors year-round or for elderly residents whose temperature-regulation reflexes are slower. A few degrees lower (64 to 66°F) is fine for households that wear sweaters and slippers indoors and want to minimize the heating bill.

The savings number gets quoted constantly: every degree lower saves roughly 1 to 3 percent on heating cost. The lower end applies to mild climates with short heating seasons. The upper end applies to cold climates with long heating seasons. A household in Boston going from 72°F to 68°F across a winter typically saves 8 to 12 percent on heating. The same change in Atlanta saves 4 to 6 percent because the total heating bill is smaller to begin with. Run your specific savings through the thermostat savings calculator against your local rates.

What temperature should you set your thermostat to in summer?

78°F is the DOE recommendation for occupied summer hours. Like the winter number, it is calibrated for typical adult comfort with normal indoor activity. The realistic comfort range runs 74 to 80°F depending on humidity, clothing, and what the outdoor temperature is doing. Three things shift the right number for a specific home.

Indoor humidity matters more than the air temperature reading. A home at 78°F and 40 percent humidity feels noticeably cooler than the same home at 76°F and 60 percent humidity. If your AC is keeping the air dry, you can run a higher setpoint comfortably. If the system runs short cycles and leaves humidity above 55 percent, no setpoint will feel right. (Our oversized HVAC signs guide walks through the cycle-time test if the AC feels cool but clammy.)

Cooling cost rises faster per degree than heating cost. Every degree cooler than 78°F typically adds 3 to 5 percent to summer cooling. The math runs faster than winter because AC works harder against high outdoor temperatures than a furnace does against cold ones. The household that runs 72°F all summer is paying 18 to 30 percent more than the 78°F baseline. That is real money in regions where cooling bills cross $200 per month.

What temperature should you set the thermostat to at night?

Sleep research at the National Sleep Foundation and Cleveland Clinic puts the optimal bedroom temperature between 60 and 67°F for adults. The mechanism is straightforward: body core temperature naturally drops 1 to 2 degrees during sleep onset, and a cool room helps that process. Rooms above 70°F or below 55°F disrupt REM cycles and produce measurably worse sleep quality in lab studies.

For winter, that means dropping the thermostat to 60 to 62°F at bedtime. This is the biggest single energy-saving move available because you are setting back across an 8-hour window when no one cares about the temperature. The setback works whether you have central heat, mini splits, or a boiler, with one exception: heat pumps with electric resistance backup can lose the savings during morning recovery if the strips have to run. The thermostat savings calculator covers the heat pump recovery penalty in detail.

For summer, sleeping comfort runs 72 to 75°F. Sleep research bottoms out below about 65°F because shivering kicks in. The thermostat-up-to-78-at-bedtime advice that some energy sources promote does not match human biology. The right summer night setting is cooler than the daytime setting, not warmer.

What temperature should you set the thermostat to when no one is home?

Away periods are where the biggest setbacks pay off. In winter, dropping the thermostat to 58 to 62°F while you are at work or out for the day saves 7 to 12 percent of the heating bill in most homes. In summer, raising it to 82 to 85°F saves 8 to 15 percent of cooling cost. The DOE's 10 percent rule of thumb assumes an 8-hour setback at 7 to 10 degrees off the home setpoint, which is exactly the workday window most US households have.

Three constraints on how far you can set back.

• Pets: dogs are comfortable 60 to 80°F. Cats tolerate 50 to 85°F. Both prefer somewhere in the middle of the human comfort range. Set winter away at 60°F minimum if you have pets, summer away at 80°F maximum.
• Plumbing freeze risk: pipes in unheated walls can freeze when indoor air drops below 55°F in cold climates. Keep winter away at 58°F minimum in zones 5 through 7.
• Plants: most houseplants tolerate 55 to 85°F. Tropical plants (orchids, ferns) suffer below 60°F. Cacti and succulents tolerate any temperature above freezing.

The smart thermostat advantage on away periods is geofencing: your phone's location tells the thermostat when the house is empty and when it is being approached for arrival, so the system can run the deep setback all day and recover before you walk in the door. Programmable thermostats do the same thing on a fixed schedule, which works if your schedule is regular. Both approaches save the same amount once set up correctly.

Vacation thermostat settings: how low or high can you go?

Extended absences (3+ days) are the most aggressive setback opportunity. The temperature only needs to stay safe for the building and any pets staying behind. Specific limits:

• Winter vacation, no one home: 55°F if your home has any plumbing in exterior walls; 50°F if all plumbing is in interior walls or insulated against freeze. Below 50°F, condensation risk rises on cold surfaces and the savings flatten.
• Summer vacation, no one home: 85 to 90°F for a few days is fine. Beyond a week at 90°F+, indoor humidity climbs and can damage wood furniture, instruments, and artwork. Many smart thermostats include a 35 percent maximum humidity override that turns the AC back on when humidity crosses the threshold even if temperature is below the setpoint.
• Either season, pets staying behind: 65 to 75°F. Do not setback for vacation if a pet sitter is not checking on the animal daily.

The savings on a one-week winter vacation set to 55°F instead of 68°F is typically $40 to $90 depending on heating fuel and climate zone. The savings on a summer vacation set to 85°F is $30 to $70. Modest but worth the 30 seconds it takes to set vacation mode on your way out the door.

Thermostat settings for babies, toddlers, and elderly residents

The American Academy of Pediatrics recommends a baby's room stay between 68 and 72°F year-round. Babies cannot regulate their body temperature efficiently and overheating is a SIDS risk factor through about 6 months. For households with infants, tighten the seasonal setpoints: 70°F winter day and night, 72°F summer day, 70°F summer night. Avoid deep setbacks until the child is over a year old.

Elderly residents (70 and older) have slower thermoregulation and higher risk of hypothermia indoors at temperatures most adults find comfortable. CDC guidance puts the minimum safe indoor temperature for older adults at 65°F. Households with elderly residents should run winter at 70 to 72°F continuously and avoid setbacks below 68°F. Summer cooling at 76 to 78°F is fine; the heat-risk threshold for elderly residents is closer to 80°F indoor sustained.

For households with both a baby and an elderly resident, the 70°F year-round target is the safe overlap. You lose some setback savings but the comfort and health margin is worth it.

Working from home: when does the work-hours setback go away?

The traditional weekday schedule (warm at 6 AM, cool at 8 AM, warm at 5 PM) was built around commuters. Working from home erases the 9-to-5 setback window because the house is occupied. The right schedule for a remote worker drops the setback to just sleeping hours plus weekday morning runs to the gym or kids' school.

The savings hit is real but smaller than people expect. A typical 8-hour weekday setback saved 8 to 12 percent of seasonal heating cost. Losing it costs back about half that, or 4 to 6 percent, because the sleeping setback (still 8 hours) is doing most of the work. The full math is in the thermostat savings calculator where you can compare 1-setback vs 2-setback schedules at your specific rates.

The hybrid schedule (in-office some days, home others) is where smart thermostats actually earn their cost. Geofencing handles the variable occupancy automatically. A programmable thermostat without geofencing usually defaults to the home schedule on Mondays-Wednesdays-Fridays (or whatever your in-office days are), which is the wrong setting on the days you stay home.

Single-stat vs multi-zone setpoints

Most US single-family homes have one thermostat covering the whole house. The setpoint above the thermostat is the average of every room's comfort, weighted by where the thermostat happens to be installed. The upstairs bedrooms run 3 to 6 degrees warmer than the downstairs thermostat in summer (because heat rises) and 3 to 6 degrees cooler in winter (because heat rises away from them). A 72°F setpoint on the downstairs thermostat usually means 76 to 78°F upstairs in summer and 66 to 68°F upstairs in winter, which is why the upstairs bedroom feels uncomfortable even though "the thermostat is set right."

The fixes, in order of cost:

• Move the thermostat: $150 to $400 for an electrician to relocate to a more representative wall. Best if the current spot is in a hallway or near a kitchen and not where people actually sit.
• Add a remote temperature sensor: $50 to $100 for compatible smart thermostats (Ecobee, Nest, Honeywell T9). The sensor lives in the problem room and tells the thermostat to use that reading instead of the main one.
• Add zoning: $3,000 to $8,000 to install motorized dampers and zone control panel. Each zone gets its own thermostat. Best for 2-story homes with persistent comfort mismatches.

The schedules that actually work for most households

Three template schedules that cover most US households. Pick the one that fits and adjust from there.

Traditional 9-to-5 household (winter): 68°F from 6 AM to 8 AM, 60°F from 8 AM to 5 PM, 68°F from 5 PM to 10 PM, 62°F from 10 PM to 6 AM. Saves 12 to 18 percent of winter heating cost over flat 68°F.

Traditional 9-to-5 household (summer): 78°F from 6 AM to 8 AM, 84°F from 8 AM to 5 PM, 78°F from 5 PM to 10 PM, 75°F from 10 PM to 6 AM. Saves 10 to 15 percent of summer cooling cost over flat 75°F.

Remote worker household (winter): 68°F from 6 AM to 10 PM, 62°F from 10 PM to 6 AM. Saves 5 to 8 percent over flat 68°F.

Remote worker household (summer): 78°F from 6 AM to 10 PM, 75°F from 10 PM to 6 AM. Saves 3 to 5 percent over flat 75°F.

Household with baby or elderly resident (any season): hold target temperature within 2 degrees year-round. Skip aggressive setbacks. Smart thermostat investment is wasted at this stage of life; a basic stat works fine.

Run any of these schedules through the thermostat savings calculator against your specific utility rates to convert the percentage savings into actual dollars. The operating cost calculator will show the baseline monthly bill before any setback strategy.