Heating and cooling account for nearly half of the average home's energy bill. The good news: adjusting your thermostat settings costs nothing and can cut that bill by 10–15%, according to the U.S. Department of Energy. The key is knowing which temperatures to set, when, and why the math works the way it does. Here's everything you need, backed by real numbers.

The DOE's Recommended Thermostat Settings

The Department of Energy recommends specific temperature targets based on time of day and whether you're heating or cooling. These settings balance comfort with maximum efficiency:

Winter (Heating Season)

  • When home and awake: 68°F (20°C)
  • When asleep or away: 60°F (15.5°C) — set back 8°F or more

Summer (Cooling Season)

  • When home: 78°F (25.5°C)
  • When away: 85°F (29.5°C) — raise it 7°F or more
  • When asleep: 82°F (27.8°C) — most people sleep well with a fan assist

These numbers aren't arbitrary. They represent the point at which your system runs minimally while maintaining acceptable conditions. Each degree matters — more on that below.

How Much Does Each Degree Cost?

The DOE estimates that every 1°F of setback for 8 hours saves approximately 1% on your heating or cooling bill. That means:

  • Turning heat down from 70°F to 62°F overnight (8°F setback, 8 hours) saves ~8% daily on heating costs during those hours
  • Raising AC from 72°F to 78°F when leaving for work (6°F setback, 10 hours) saves ~6–8% on cooling costs per day
  • Combined winter + summer setbacks: $150–250/year saved for a typical U.S. home

These savings assume the home reaches setback temperature within about an hour — which is true for most well-insulated homes with properly sized HVAC. To estimate your full heating and cooling costs, use our Heating vs Cooling Cost Calculator.

The Best Setback Schedule: By Time of Day

A programmable or smart thermostat lets you automate setbacks to match your schedule. Here's a recommended daily schedule for a typical household:

Weekdays

  • 6:00 AM: Ramp to comfort temperature (68°F heat / 78°F cool) — 30 min before waking
  • 8:00 AM: Set back when house empties (60°F / 85°F)
  • 5:00 PM: Ramp back to comfort temperature before you arrive
  • 10:00 PM: Set back for sleep (60–64°F / 82°F)

Weekends

If you're home all day, keep the comfort temperature without setbacks. The savings come from the overnight setback, which still applies every day of the year.

Does Turning the Heat Off Completely Save More?

This is one of the most common thermostat myths. Turning the heat entirely off and reheating from 50°F to 68°F does not save more than a moderate setback. Here's why:

Your heating system works at the same efficiency regardless of how far it has to raise the temperature. But heat loss from your home follows physics: the bigger the difference between inside and outside temperature, the faster heat escapes. By keeping the setback moderate (8–10°F rather than complete shutdown), you reduce how fast the home cools, and you avoid the burst of energy needed to reheat a very cold space.

The DOE-recommended 8°F setback hits the sweet spot: enough temperature reduction to save meaningfully, not so extreme that reheating costs offset the savings. For homes in extreme cold climates (below 0°F nights), even a 5–6°F setback is effective — pushing lower risks frozen pipes in poorly insulated areas of the home.

Smart Thermostats vs Programmable: Which Saves More?

Both can deliver 10–15% savings, but they do it differently:

  • Programmable thermostats ($25–80): You set a fixed schedule. Works perfectly if your schedule is consistent. Savings are fully predictable. Payback in 1–3 months.
  • Smart thermostats ($150–300, e.g. Nest, Ecobee): Learn your schedule, respond to occupancy, integrate with weather forecasts, and allow remote control via smartphone. Average reported savings are 10–12% on heating and 15% on cooling, with some users reporting higher. Payback period is 1–2 years.

If you already have a programmable thermostat and use it consistently, the incremental savings from upgrading to smart may not justify the cost. If you have no setback schedule at all, either option delivers meaningful savings immediately.

Humidity and the "Feels Like" Effect

Temperature settings interact with humidity in ways that significantly affect comfort at any given thermostat number:

  • In summer: At 78°F, 50% relative humidity feels comfortable. At 78°F with 70% humidity, it feels like 83°F. Running a dehumidifier or ensuring your AC is properly sized (not oversized, which causes short-cycling and poor dehumidification) lets you tolerate warmer thermostat settings without discomfort.
  • In winter: At 68°F with 30% humidity, air feels dry and cool. At 68°F with 45% humidity, it feels warmer and more comfortable. A whole-home humidifier in winter lets some people drop the thermostat 2–3°F without noticing — saving another 2–3% on heating bills.

Thermostat Settings by HVAC System Type

The rules above apply broadly, but system type matters for some specifics:

  • Gas furnace: Handles setbacks perfectly. Standard advice applies. Deep setbacks (10°F+) are fine in most climates.
  • Heat pump: More nuanced. Heat pumps are most efficient running continuously at a moderate temperature rather than large setbacks that require the backup electric resistance heating to kick in. For heat pumps, limit setbacks to 2–4°F rather than 8°F — or use a smart thermostat with a heat-pump-specific algorithm. See our Heating Cost by Fuel Type Calculator to compare.
  • Electric baseboard: Standard setback advice applies. Zone heating (heating only occupied rooms) amplifies savings significantly.
  • Central AC: Standard advice applies. Pre-cooling the house in the morning before peak rate periods (if you're on time-of-use pricing) can further reduce costs.

The "Away" Setting: How Long Does It Take to Reheat?

A common concern is coming home to a cold house. Here's what to expect:

  • A well-insulated home (2,000 sq ft) drops about 1°F per hour on a cold day when the furnace is off
  • An 8-hour setback from 68°F to 60°F means the house needs to be reheated ~8°F
  • A properly sized furnace can raise indoor temperature 2–3°F per hour, so full reheat takes 3–4 hours
  • Program your thermostat to start reheating 2–3 hours before you arrive, not when you walk in the door

When Not to Setback

There are situations where aggressive setbacks aren't recommended:

  • Extreme cold snaps (below -10°F): Risk of frozen pipes in poorly insulated wall cavities or crawl spaces. Keep minimum temperature at 55°F.
  • Vacation in winter: Keep minimum at 55°F for pipe protection. Don't turn heat entirely off.
  • Homes with radiant floor heating: These systems have high thermal mass and take much longer to reach setpoint. Smaller, less frequent setbacks are more appropriate.
  • Older or sick occupants: Comfort and health needs may override maximum savings settings. The DOE recommendations are starting points, not mandates.

Putting It All Together: Your Annual Savings Estimate

For a home spending $1,800/year on heating and cooling combined:

  • Winter overnight setbacks (8°F, ~8 hrs/night, Oct–Apr): saves ~$90–120/yr
  • Winter away-from-home setbacks (8°F, ~9 hrs/day, Oct–Apr): saves ~$60–80/yr
  • Summer away setbacks (6°F, ~9 hrs/day, Jun–Sep): saves ~$40–60/yr
  • Total: $190–260/year for a home spending $1,800 on HVAC

That's 10–14% of the annual HVAC budget, achieved simply by adjusting the schedule. To see exactly how much heating vs cooling costs in your situation, run the numbers through our Heating vs Cooling Cost Calculator — then apply the percentage savings from thermostat setbacks to your specific numbers.