Thermostats and zoning

Think of the thermostat as the switch for your heating and cooling. Low-voltage electric controls use electrical energy to work the control devices of a heating and cooling system. Because it reacts to the air right around it, where it sits matters a great deal.

Install your thermostat away from heating or cooling registers, appliances, lights, doorways, fireplaces, skylights and windows, and away from direct sun or drafts; interior walls are best. If yours sits near one of these, ask about moving it.

Source: U.S. EPA

Most newer thermostats do more than hold one temperature. Programmable thermostats can adjust temperatures automatically on a schedule you set. Electronic thermostats with adaptive recovery learn from experience how to change most efficiently from one temperature to another. Smart thermostats can adjust based on whether people are home or active.

Smart models add a few more features. With a smartphone, you can adjust the temperature from anywhere with an internet connection. Some can detect when you have left for the day and set back your system to save money. Certain ENERGY STAR certified models learn your preferences and set a schedule that moves to energy-saving temperatures when you are asleep or away.

ENERGY STAR sets a few rules for the smart thermostats it certifies. They must still work as a basic thermostat without a connection to their service. They must report how your system uses energy, such as monthly run time. They must also report electric resistance heat use for heat pumps.

Source: U.S. Department of Energy · ENERGY STAR

Not every thermostat works with every system. Make sure a smart thermostat is compatible with your heating and cooling system before you buy it. If you have a heat pump, you may need a special programmable thermostat to make the most of your savings all year. In a dual-fuel system, the thermostat first brings on the heat pump and only switches to the furnace if the heat pump cannot meet the call for heat. A technician can look at your wiring and equipment and tell you which models will work.

Source: ENERGY STAR · U.S. EPA · Natural Resources Canada

The best setting is one that matches your day. Check your thermostat settings so the system keeps you comfortable when you are home and saves energy while you are away. A thermostat that sets back the temperature when you leave saves money on your heating or cooling bill. With heat pumps, the indoor fan speed is in general most efficient on auto, and fixing one speed can reduce capacity and efficiency.

Heating and cooling should not fight each other. EPA's design manual for its own buildings calls for a 5°F dead band, a gap where neither heating nor cooling runs, between heating and cooling in the same zone. Ask your technician how your own system handles the switch.

Source: ENERGY STAR · U.S. Department of Energy · U.S. EPA

Zoning lets one system heat and cool parts of your home differently. A typical zone control system uses automatic dampers in the ducts that open and close as each zone's thermostat calls. Each zone's heating and cooling should be controlled by a thermostat or sensor located in that zone. If you have more than one zone, use a programmable thermostat for each one. Ask about zoning if one floor of your home is always warmer than another.

Source: AHRI · U.S. EPA

A blank screen is worth checking before you call. Change the batteries each year if your programmable thermostat runs on them, and note that some units tell you when they need changing. If new batteries do not bring the screen back, a technician can check the thermostat and its wiring.

A thermostat is part of your yearly check-up. A qualified contractor's yearly inspection of the heating system should include the thermostat controls and the automatic safety switches. In Chicago, installing or removing a thermostat needs no building permit, though installing new low-voltage wiring generally does.

Source: U.S. EPA · U.S. Consumer Product Safety Commission · City of Chicago