It takes the shape of an unassuming box on the wall, but that modest device controls the comfort of your home on the coldest day in Winter and the hottest day in Summer. A thermostat is a temperature-sensitive switch that controls a space conditioning unit or system, such as a furnace, air conditioner, or both.
When the indoor temperature drops below or rises above the thermostat setting, the switch moves to the “on” position, and your heater or air conditioner runs to warm or cool the house air to the setting you selected for your family’s comfort.
The location of your thermostat can affect its efficiency and performance. Place thermostats away from direct sunlight, drafts, doorways, skylights, and windows. Read and follow the manufacturer’s setting up procedures to prevent unnecessary furnace or “ghost readings” or air conditioner cycling.
A thermostat, in its simplest form, must be manually adjusted to change the indoor air temperature. This model is effective and inexpensive but there is a certain amount of inconvenience results from this strategy. For example, waking up in a cooler than normal house in the winter or possibly forgetting to adjust the thermostat (during any season) when you you’re asleep or away.
To maximize your energy savings without sacrificing comfort, you can install an automatic setback or an electronic programmable thermostat. They adjust the temperature setting for you. You can set it to raise the temperature before you wake up and spare you some discomfort. While you might forget to turn down the heat before you leave for work in the morning, a programmable thermostat won’t! By maintaining the highest or lowest required temperatures for four or five hours a day instead of 24 hours, a programmable thermostat can pay for itself in energy saved within four years.
Most of the programmable thermostats perform one or more of the following energy control functions: Store and repeat multiple daily settings, which you can manually override without affecting the rest of the daily or weekly program. They too can tore six or more temperature settings a day. They adjust heating or air conditioning turn-on times as the outside temperature changes.
You don’t have to go high-tech to be energy efficient. Another way to cut back on your power bill is to clean and change your filter at least as often as the manufacturer suggests. You should also make sure your AC coils are clean. Not doing either can cause a unit to malfunction.
Electronic thermostats have made it easy to keep a home’s climate under control. It’s pretty much a glorified time clock, you tell it what temperature to maintain at certain times. It’s well worth if you’re going to be gone during the day. However, if you aren’t away from your home all day long, it might not be that functional. If someone is always in the house, a manual thermostat is the best option because the person will want to adjust it to the actual circumstances to be comfortable.
When you leave for the day, set it up to a lower temperature. The longer your house remains at the lower temperature, the more energy you save. This is because the fuel required to reheat a building to a comfortable temperature is roughly equal to the fuel saved as the building drops to the lower temperature. You save fuel between the time that the temperature stabilizes at the lower level and the next time heat is needed. It should be bumped up at least seven degrees during the day and four degrees warmer at night.
In the summer, you can follow the same strategy with central air conditioning, too, by keeping your house warmer than normal when you are away, and lowering the thermostat setting to 78°F (26°C) only when you are at home and need cooling.
There are five basic types of automatic and programmable thermostats:
Electromechanical (EM) thermostats, usually the easiest devices to operate, typically have manual controls such as movable tabs to set a rotary timer and sliding levers for night and day temperature settings. These thermostats work with most conventional heating and cooling systems, except heat pumps. EM controls have limited flexibility and can store only the same settings for each day, so they are best suited for people with regular schedules.
Digital thermostats are identified by their LED or LCD digital readout and data entry pads or buttons. They present the widest range of features and flexibility, and digital thermostats can be used with most heating and cooling systems. They provide precise temperature control, and they permit custom scheduling. But you won’t save energy if you don’t set the controls or you set them incorrectly. Therefore, make sure you are comfortable with programming the functions and operations of the one you choose.
Hybrid systems combine the technology of manual slides and knobs with digital controls to simplify use and maintain flexibility. Hybrid models are available for most systems, including heat pumps.
Occupancy thermostats maintain the setback temperature until someone presses a button to call for heating or cooling. They do not rely on the time of day. The ensuing preset “comfort period” lasts from 30 minutes to 12 hours, depending on how you’ve set the thermostat. Then, the temperature returns to the setback level. These units offer the ultimate in simplicity, but lack flexibility. Occupancy thermostats are best suited for spaces that remain unoccupied for long periods of time.
Light sensing heat thermostats rely on the lighting level preset by the owner to activate heating systems. When lighting is reduced, a photocell inside the thermostat senses unoccupied conditions and allows space temperatures to fall 10° below the occupied temperature setting. When lighting levels increase to normal, temperatures automatically adjust to comfort conditions. These units do not require batteries or programming and reset themselves after power failures.
Most automatic and programmable thermostats completely replace existing units. These are preferred by many homeowners. However, some devices can be placed over existing thermostats and are mechanically controlled to permit automatic setbacks. Don’t forget to make sure your thermostat is conveniently located for programming.
The best thermostat for you will depend on your life style and comfort level in varying house temperatures. While automatic and programmable thermostats save energy, a manual unit can be equally effective if you diligently regulate its setting.