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How to Program a Thermostat (Even an Old One)

Published October 2026 7 min read Beginner-friendly

A programmable thermostat is the highest-ROI home upgrade most people never bother with. The device itself costs $30–$60, and once programmed it runs on autopilot for years. A correctly set schedule saves $100–$150 per year — meaning the device pays for itself in a single heating or cooling season.

Most programmable thermostats are never actually programmed. People buy them, mount them, and then leave them at a single setting, losing all the savings. The setup takes 15 minutes. Here's how to do it right, no matter what kind of thermostat you have.

Step 1: Identify your thermostat type

Manual thermostat

Has a dial or two up/down buttons. No digital display for scheduling. You can still save money with a manual — you just have to change the setting by hand when you leave and when you come home. This costs nothing and works, but relies on habit.

Programmable thermostat

Has a digital display, buttons for time, temperature, and usually a "Program" or "Schedule" button. Lets you set different temperatures for different times of day, and often different schedules for weekdays and weekends.

Smart thermostat

Has Wi-Fi, a mobile app, and often a motion sensor. Learns your schedule automatically over the first week. Brands: Nest, Ecobee, Honeywell Home, Amazon Smart Thermostat. Setup is done through the app rather than on the device itself.

Step 2: Plan your schedule on paper first

Before touching the thermostat, write down what you actually want. Every programmable thermostat uses the same four-period structure:

Now write your target temperatures for each period, for both heating and cooling seasons:

Winter settings

Summer settings

If you work from home, use the Home temperature during the day instead of Away. If your schedule varies day-to-day, either use a "weekday/weekend" split or upgrade to a smart thermostat that learns your pattern.

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Finding your comfort range: If 68°F feels too cold in winter, try 70°F — a setback of 8°F instead of 10°F still saves about 8%. It's better to run a slightly less aggressive schedule you'll actually keep than to fight yourself with a schedule you hate.

Step 3: Enter the schedule

On a typical Honeywell programmable thermostat

  1. Press Set or Program
  2. Press Wake → set time using up/down arrows → press Next
  3. Set temperature → press Next
  4. Repeat for Away, Home, Sleep
  5. Press Done or Run to save

On a typical Emerson or White-Rodgers model

  1. Press Menu → Schedule or Program
  2. Select day of week (or "Mon-Fri" / "Sat-Sun" / "All")
  3. Set wake time and temperature
  4. Repeat for each period, using Next or arrow buttons to navigate
  5. Press Save to lock in

On a Nest smart thermostat

  1. Open the Google Home app (or Nest app)
  2. Tap your thermostat → Settings → Schedule
  3. Turn off "Auto-Schedule" if you want manual control, or let it learn for a week
  4. Tap a time slot → set temperature → tap Save
  5. For Eco mode (the "away" temperature), go to Settings → Eco → set your away target

On an Ecobee smart thermostat

  1. Open the Ecobee app → tap your thermostat
  2. Tap Comfort Settings → Schedule
  3. Tap a time period → set temperature
  4. Ecobee includes a "Smart Home / Smart Away" feature by default — this is the same as wake/away in other thermostats

Step 4: Set the season switch

Most programmable thermostats have a heating/cooling/auto switch. If yours does, set it to Auto so the thermostat decides when to heat or cool based on your setpoints. The "Auto" setting prevents accidentally heating your house in summer.

If your thermostat uses separate heating and cooling schedules (older Honeywell models do this), you'll need to program both. Do the heating schedule first, then switch to cooling and enter the summer settings.

Step 5: Test for one week

Run the schedule for a full week before making changes. Within that week:

After a week, adjust by one or two degrees if something feels off. Don't change more than one thing at a time — the whole point is to identify what actually doesn't work.

What it saves

A correctly programmed thermostat versus leaving it at a constant temperature:

If you also upgrade to a smart thermostat, add $40–$80 per year from geofencing (automatic away detection) and learning features. The smart thermostat costs more upfront ($100–$250) but pays back in 1–2 seasons.

Frequently Asked Questions

Can I program a thermostat if my landlord controls the heating system?

Only if you have direct access to the thermostat. In buildings with central controls, you can't program the thermostat, but you can still save energy by sealing drafts, using ceiling fans, and closing doors of unused rooms.

What if I have a heat pump?

Use smaller setbacks — 3–5°F instead of 10°F. Larger setbacks trigger the auxiliary heat strips, which use much more electricity. Many smart thermostats have heat pump-specific logic that handles this automatically.

Is a smart thermostat worth the extra cost over a programmable one?

If your schedule is irregular, you travel frequently, or you want to control the temperature remotely — yes. If you have a stable 9-to-5 schedule, a $40 programmable thermostat gives you most of the savings for a fraction of the price.

What if I forget to change the schedule when daylight saving time changes?

Modern programmable thermostats handle DST automatically. Older ones may not — check the manual or update the time manually twice a year. Smart thermostats sync automatically.

Does my thermostat need to be re-programmed seasonally?

Yes, if your thermostat has separate heating and cooling schedules. You switch between them once in spring and once in fall. Smart thermostats do this automatically based on outdoor temperature.

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