Recommended Thermostat Settings for Summer and Winter

The short answer

In winter, the US Department of Energy suggests setting your thermostat to around 68 to 70°F (20 to 21°C) while you're awake and lower while you sleep or are away (DOE thermostats). In summer, set it as high as is comfortable when you're home; 78°F (26°C) works as a common target and saves real money over 72°F (DOE summer tips). Turning the thermostat back 7 to 10°F for 8 hours a day can save as much as 10% a year on heating and cooling (DOE Energy Saver Guide). Keep winter temperatures higher for babies, older adults, and anyone with heart or lung disease.

Suggested thermostat settings by season and time of day

Use this as a starting point. Your house, your climate, and your body will nudge it.

| Season | When | Suggested setting | |---|---|---| | Winter | Home and awake | 68 to 70°F (20 to 21°C) | | Winter | Asleep or away | 7 to 10°F lower than your daytime setting | | Summer | Home and awake | As high as is comfortable; 78°F (26°C) is a common target | | Summer | Away | Warmer than normal, then cool before you get home | | Summer | Asleep | Whatever lets you sleep well (see below) |

Two guardrails sit on top of this table. In winter, the World Health Organization treats 18°C (64.4°F) as a safe minimum for the general population and says vulnerable groups may need more (WHO 2018). In summer, don't let the house get dangerously hot for an older adult, a baby, or a pet just to save a few dollars.

Best thermostat setting for winter

The DOE recommends around 68 to 70°F while you're up and about (DOE thermostats). That range keeps most people comfortable in normal indoor clothes and costs less than higher settings.

To save money, add a setback. The DOE says you can save as much as 10% a year on heating and cooling by turning the thermostat down 7 to 10°F for 8 hours a day in fall and winter (DOE Energy Saver Guide). Savings run proportionally larger in milder climates (DOE thermostats). Overnight works well for this since you're under blankets anyway. If you like a cooler bedroom, start the setback a bit before you actually go to bed (DOE thermostats). For the sleep side of the question, see the best temperature for sleep.

A popular worry says the furnace burns all the savings warming the house back up. The DOE explains otherwise: once the house cools, it loses heat to the outdoors more slowly, so the longer it stays cooler, the more you save (DOE thermostats).

Heat pump owners, take note. A deep setback can switch on backup electric resistance heat, which costs more to run (DOE Energy Saver Guide). Use a smart or programmable thermostat designed for heat pumps, or keep a moderate, steady setting (DOE thermostats).

Is 72 a good temperature for heat in the winter?

It's a comfortable, safe temperature for most homes. It's also 2 to 4°F above the DOE's suggested range, so you'll pay more to hold it (DOE thermostats). If 72°F feels right and the bill doesn't bother you, keep it; for most people it poses no health concern.

The interesting part: why does 72°F feel chilly in January and pleasant in July? Your thermostat reads one number, air temperature. Comfort depends on six. ASHRAE Standard 55, the engineering standard for indoor comfort, counts air temperature, thermal radiation, humidity, air speed, clothing, and activity level (ASHRAE 55). In winter several of those shift against you:

• Cold walls and windows. Your body trades heat with the surfaces around you by radiation. Sit near a cold window and you lose heat to it even when the air reads 72°F.
• Drafts. Moving air carries heat off your skin faster.
• Clothing. People often wear lighter clothes indoors than the season calls for, or step out of a hot shower into a cool hallway.
• Activity. Sitting still on the couch makes far less body heat than walking around.

In July, the same 72°F air sits next to sun-warmed walls, and you feel fine in shorts. Same number, different room. That gap explains why the perfect temperature changes and how the feels like temperature works outdoors too.

Practical fixes before you crank the heat: close curtains at night, move your chair away from the window, seal drafts, and wear a sweater.

What is the ideal temperature for a house in winter for health?

For healthy adults, the comfort range above covers it. The health floor matters more for the people who struggle with cold.

The WHO Housing and Health Guidelines strongly recommend keeping homes warm enough to protect residents from the harmful effects of cold, and propose 18°C (64.4°F) as a safe indoor temperature for the general population during cold seasons (WHO 2018). The WHO links cold homes to breathing problems and heart and blood vessel strain, and notes that older people, children, and people with chronic illness, particularly heart and lung disease, may need a higher minimum (WHO 2018).

That last point matters. If you or a parent has heart failure, coronary disease, or COPD, consider a gentler overnight setback and keep the house comfortably warm. Your doctor can help you decide what suits you.

Best thermostat setting for summer

The DOE advice for summer: keep the house as warm as is comfortable when you're home, warmer than normal when you're away, and let a schedule bring it back down before you return (DOE thermostats). A DOE tip puts numbers on it: running air conditioning at 78°F instead of 72°F can save 6 to 18% on your cooling bill (DOE summer tips).

A few things make a higher setting feel better:

• Run a ceiling fan. The DOE says a fan lets you raise the thermostat about 4°F with no loss in comfort. A fan cools you by moving air over your skin, so turn it off when you leave the room (DOE Energy Saver Guide; DOE summer tips).
• Control humidity. The DOE notes your settings should still keep humidity in check (DOE thermostats). Damp air at 78°F feels warmer than dry air at 78°F.
• Don't set it extra low to cool faster. The air conditioner won't cool the house any quicker, and you'll likely overcool and overpay (DOE thermostats).

Heat and older adults. Older adults handle sudden temperature changes less well and more often take medicines or have conditions that affect how the body handles heat (CDC heat and older adults). The CDC advises staying in air conditioning during hot weather and not relying on a fan as your main cooling source when it's really hot outside. If an older relative lives alone, check on them during heat waves.

Smart and programmable thermostats

A programmable thermostat runs your setbacks on schedule so you don't have to remember. A smart thermostat adds Wi-Fi, remote control from your phone, energy reports, and often learns your preferred temperatures and builds the schedule for you (DOE Energy Saver Guide). ENERGY STAR certified models have been independently certified, based on field data, to deliver energy savings (DOE Energy Saver Guide).

The best schedule follows your life: when you wake, leave, come home, and go to bed, and everyone else in the house too (DOE thermostats). Just Right can set an Apple Home thermostat for the day's weather and time of day if you'd rather not fiddle with it yourself.

The bottom line

• Winter: about 68 to 70°F (20 to 21°C) while you're home and awake, 7 to 10°F lower while you sleep or are away.
• Summer: as warm as is comfortable at home, around 78°F (26°C) for many people, with a ceiling fan doing some of the work.
• 72°F in winter is fine for your health and just costs a bit more.
• Protect the vulnerable: keep homes above 64°F (18°C) in winter, warmer for older adults, babies, and anyone with heart or lung disease, and make sure older adults can stay cool in summer heat.

If someone shows signs of heat stroke, such as confusion, fainting, or a very high body temperature, call 911. Learn the early warning signs in heat stress symptoms.