Selecting the proper temperatures throughout the day and night can be a bit confusing as you balance comfort with energy and dollar savings.
It does save energy overall if you lower the temperature setting on your central furnace or heat pump thermostat. The actual amount of dollar savings depends primarily on how low you set the thermostat, how long you have it set back and, to a lesser degree, your climate.
There also are other advantages to lowering the thermostat setting during winter. A lower house temperature requires less moisture indoors to keep the indoor air at a given relative humidity level. A heating system that runs less at a lower temperature means the equipment will last longer.
There is not a “best” thermostat setting for all homes and climates. The lower you set it, the greater the overall savings will be. The amount of savings per degree for each nighttime, eight-hour setback period ranges from 1% to 3%.
Unless there are some health problems in your family, 62 degrees is typically comfortable if you are wearing long sleeves or a sweater.
Important note: programmable thermostats generally are not recommended for heat pumps. Do not change heat pump thermostat settings more than 1 or 2 degrees. Consult the manufacturer’s manual or contact your co-op’s energy advisor for more information.
It is a common myth that it takes as much energy to reheat a house—in the morning, for example—as was saved during the overnight temperature setback. The amount of heat a house loses through its walls, ceilings and floors is directly proportional to the difference between the indoor and the outdoor temperatures. Air leakage also increases with larger temperature differences.
When the indoor temperature is set lower, the indoor-to-outdoor temperature difference is smaller, so less heat is lost from your house. That means your furnace has to use less gas, oil or electricity to create the heat to replace it—which is less than the amount saved over the temperature setback period. During the summer, the same concept applies with air conditioning.
JAMES DULLEY is a nationally syndicated columnist who writes on energy efficiency and do-it-yourself energy topics.