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Read the manual. Determine your schedule. Program time and date information. Press the "set" or "program" button. Press "set" or "program" again to set a temperature. Set the "leave" time and temperature. Set the "return" time and temperature. Set the "sleep" time and temperature. Repeat the process for the weekend. Press the "run" button to initiate.
While all programmable thermostats have roughly the same functions, they aren't universally operated in the same manner. If you have the manual for your thermostat, keep it handy in case it has a unique set of operations. Track when you leave the house (or workplace) and are away regularly for at least 4 hours. Make notes about your schedule for 7 days, including all 24 hours each day. The current time and date must be entered into your programmable thermostat for it to function properly. Nearly all thermostats have a button that reads "set" or possibly even "day/time" Press this button and a clock will appear on the display for you to set the time and the date. Use the up and down arrows to set the items and press the same "set" or "day/time" button again after each step to proceed to the next. Prompts will indicate whether to enter the time as a twelve-hour increment or as a twenty-four-hour figure. You may also need to set the day of the week, but it will follow in the same process after the time and date. Once you have the date and time programmed, you are ready to program the thermostat's schedule. Some brands will have an actual "program" button, whereas others may require you to scroll past the time and date information by hitting the "set" button several times. You will reach a screen on the display where it prompts you to set a "wake" time for weekday mornings. You may actually want to set the time very slightly before you wake up so that the system is already running. Most thermostats will allow you to schedule weekdays and weekends separately, whereas some may allow you to schedule each day separately. Again, you can use the up and down arrows to cycle through the time. With the "wake" time set, you will now have to set the "wake" temperature. Press the respective button for your model thermostat again and the temperature will begin blinking. Use the up and down arrows to find the temperature you want. Some models may allow you to set a temperature range so that you don't have to reprogram the thermostat with each season. For example, it may prompt you to set both a wake summer and winter temperature. This will ensure that the system heats when the ambient temperature is below a certain threshold and cools when above another threshold. With the "wake" time and temperature set, the thermostat will prompt you to schedule the time you leave for the day during the week. Most people set these temperatures much higher during the summer or lower during the winter to conserve energy and run the system less while no one is home. Use the same process of hitting the "set" or "program" button and the up and down hours to cycle through and find the settings you want. If you don't want the system to run at all while you're away, you can simply set it to turn on at a temperature that you know your home won't reach. The next time and temperature setting the thermostat will request is for what time you return home during the week. As with the "wake" setting, you may want to set the time fifteen-to-thirty minutes before you get home if you want to ensure that the home has already reached the temperature when you arrive. The fourth and final weekday setting the thermostat will request is for the time you go to sleep at night. Since many people might open windows during summer nights or pile on extra blankets during the winter, you can save money and energy by respectively raising or lowering the overnight temperature setting. Wherever you set this temperature will hold over until the "wake" time and temperature you have set for the following morning. Once you finish setting the weekday schedule, the thermostat will prompt you to set the same four timeswake, leave, return, and sleepfor the weekend. As with the other settings, keep using the "set" or "program" button in order to advance the menu and keep using the arrows to adjust the times and temperatures. Depending on your thermostat model, once you hit "set" or "program" on the final weekend "sleep" settings, it may return you to the current day, time, and temperature and begin following the schedule. Other models may have a "run" button that you must press to initiate the schedule.