Thermostat settings by state

Thermostat settings in Washington, DC

By Ismail Farooq · Updated 2026-10-30

How most homes heat: Natural gas furnaces and boilers in rowhouses and older buildings; heat pumps in many apartments and condos.

Washington is zone 4A: hot, humid summers and cold winters. Rowhouses often have a gas furnace in the basement with ducts to two or three floors, so upstairs bedrooms run hot in summer and cool in winter. A thermostat with a room sensor upstairs, or a two-zone system, makes a bigger difference than any schedule.

Many condos and apartments use a water-source heat pump or fan coil with its own thermostat type. Check what your unit is before buying a smart thermostat, and check your building’s rules; some don’t let residents change the thermostat.

Climate zones in Washington, DC

Zones follow county lines on the 2021 IECC map, and some counties changed zone between code editions. DOE’s Building America climate zone map lists every county.

Starting settings

• Everyday setpoints: about 68 °F in winter and 78 °F in summer while you’re home, set back while you sleep or are out (DOE’s guidance).
• Gas, oil or propane furnace or boiler: setbacks of 7 to 10 °F are fine; use the thermostat’s early-start feature so the house is warm on time.
• Heat pump: keep winter setbacks small (2 to 4 °F) so a cold morning doesn’t bring on aux heat.
• Humid summers: use fan Auto, not On, and turn on the thermostat’s dehumidify or overcool setting if the house feels damp. Keep indoor humidity under about 60%.

Heat pump lockouts for Washington, DC

If you have a heat pump, these are starting points for the outdoor temperatures that control backup heat. Your installer’s balance point is better if you have it.

Rebates

Many utilities give rebates or bill credits for smart thermostats, sometimes in return for joining a peak-day program. Programs change often, so check your electric and gas utility’s website, or search by ZIP code in the ENERGY STAR rebate finder.