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Energy Saver: Programmable Thermostat Upgrade
(continued ...) The first feature to look for on a new thermostat is that it has enough program steps to handle your typical schedule. Most folks work Monday through Friday, are sometimes home Saturday and maybe go to worship on Sunday. Count up the number of program steps you need. For this example I'll use warm-up in heating mode as the same as cool-down in cooling mode. For week days, I count morning warm-up, mid-morning set-back as everybody leaves for work or school, late-afternoon warm-up preparing for everyone's return and then late-evening set-back as everyone goes to bed. The minimum program steps needed for this examples week days are then four. Now for Saturday, maybe you spend all day at home so that is morning warm-up and late-evening set-back. In this example, that would be two program steps. On Sunday, you need morning warm-up, mid-morning set back as the family goes to worship, then a noon-ish warm-up and a late-evening setback. For Sunday then, you will need four program steps. Likely, your routine is different. Follow this example and determine the program steps needed for each day. Keep in mind that the heat/cool systems are not turned off while you're away, they simply target a lower energy target set-point.
Abilities of programmable thermostats vary widely. Common features include the ability to hold a temperature until you release the hold and override the program for an unexpected change in your schedule. Expect to find models with 4 program steps that are the same for every day of the week with manual change from heat to cool for about $25. Then there are models with 4 program steps that can be different for each of seven days and have automatic heat/cool change for about $60. One feature ...