Smart programmable thermostats
Heating and cooling when you need it most

BY JAMES DULLEY

This is a smart variable thermostat that functions with a variable-speed furnace/air-conditioner blower to control humidity and temperature. The cover is open to show the programming buttons. (Photo courtesy of Trane.)

Dear Jim: We are trying to keep our utility bills low by setting the thermostat lower at night, but we hate waking up to cold bedrooms. Are the new smart thermostats easy to install and program for comfort? —Meg T.

Dear Meg: Setting your thermostat lower at night during winter (higher during summer) will save a tremendous amount on your utility bills. A common misconception is that it takes more energy to reheat or cool your house after a temperature setback or setup. Whenever your house temperature is closer to the outdoor temperature, less heat is lost or gained. This means your furnace or air conditioner has to run less overall and you save money.

By installing a “smart” thermostat, you can go to bed and wake up to a comfortable house and never know the thermostat changed itself overnight while you slept. The change in the indoor temperature overnight is very gradual, particularly in an energy-efficient house, so your body does not sense the changing temperature.

Most new smart thermostats from your heating contractor or from a home center store allow you to set different temperatures during four periods throughout the day and night. You can set the time periods to your family’s schedule. Just as setting the thermostat lower at night saves energy, additional energy is saved if the thermostat is set lower while you are at work or at school.

A weekday winter schedule for the typical family might be 70 degrees from 6-8 a.m. When everyone leaves for school or work, the program sets back to 58 degrees. When the kids get home at 3 p.m., it is already back up to 68 degrees. At 11 p.m., when everyone goes to bed, it drops to 60 degrees overnight.

Newer thermostats have followed the lead of other electronic items and are now smarter and easier to program and use. Some of them sense both the indoor and outdoor temperatures and humidity levels. This data, along with memory of how long it took to warm up the house on previous mornings, allows the thermostat to determine the precise time to start the furnace to meet your schedule. Your bedrooms will be warm when your alarm goes off in the morning no matter how cold it is outdoors.

Smart thermostats are available with several simple programming methods that even the digitally challenged person can handle. For additional convenience, some smart thermostats have internal power storage so you can snap it off the wall base and program it in your easy chair. It includes a generic preprogrammed time/temperature schedule so you can use them immediately and program your personal schedule at a later time.

If this still sounds too challenging, select one of the new smart thermostat designs that resemble a tiny touch-screen computer display on the wall. The entire programming process is menu-driven by touching its screen, so there is no complicated owner’s manual or multiuse buttons to contend with. It is backlit to make it easy to see and make changes in the dark.

When shopping for a smart thermostat, you will see designations of 7, 5+2 or 5+1+1 on the packaging. These numbers refer to the thermostat’s programming flexibility. A 7-day thermostat allows you to program a different temperature schedule for every day of the week. These are ideal if your at-home schedule varies. With the prices more reasonable now, this type is generally your best choice for future flexibility. A 5+2-day thermostat allows you to program one schedule for every weekday and another schedule for the weekend. A 5+1+1-day model is the same except you can set different Saturday and Sunday schedules. For many families, these are adequate and require less programming time. You can find these smart thermostats at most home-center and hardware stores. Most thermostat wiring is safe low-voltage and color-coded, so the wiring instructions should be easy to follow for do-it-yourself installation. A heat pump thermostat has several more color-coded wires to attach. These are for the reversing valve (switching between heating and cooling) and the backup/emergency heating (often electric resistance heat).

If you have a newer heat pump with a variable-speed blower, as I do in my own all-electric home, select a smart thermostat with a humidity control. During summer, when your house is comfortably cool, but too humid, the blower motor slows down so the air moves slowly over the cooling coils. This increases dehumidification for better comfort and efficiency.

See www.dulley.com for more on smart thermostat manufacturers (25 models) listing temperature/time schedules, programming options, comfort/ convenience features, and a savings chart, or write: James Dulley, GEORGIA Magazine, 6906 Royalgreen Dr., Cincinnati, OH 45244.