When your furnace constantly kicks on and off, it is doing something those in the industry like to call short cycling. While a short cycling furnace can keep your home warm and comfortable, frequent short cycles indicate that there's something wrong, and the problem needs to be addressed by a heating and cooling professional sooner rather than later. A short cycling furnace can lead to higher utility bills and place unnecessary wear and tear on the unit, which could result in costly repairs. Fortunately, short cycling is often caused by one or more of these three things.
Clogged Air Filter
How often do you change your furnace's air filter? If you're not doing it at least once a month, it could be clogged. A dirty, clogged furnace filter causes warm air to become trapped within the unit, which can make the internal thermostat erroneously think your home is warm and cozy. When this occurs, the unit shuts off, but it will suddenly start again after your home's thermostat signals that it's actually not warm enough in the home. These constant mixed signals result in short, inefficient heating cycles.
Faulty thermostats can also cause a heating unit to short cycle. If the thermostat malfunctions and cannot read the temperature of the home properly, it can't tell the furnace when to kick on and when to kick off. Fortunately, thermostats are easy to replace. If you've checked and changed the battery but are still experiencing problems, call a heating contractor to put in a new thermostat for you. You might also want to consider the placement of your thermostat. If it is located in a sunny spot, it may think your home is warmer than it actually is due to the sun shining in on it.
Anything that decreases the efficiency of your unit can cause it to short cycle. For example, blocked vents, chimneys and ducts can prevent your home from becoming warm enough, which will make your furnace run constantly. Additionally, if your unit is not large enough or powerful enough for the size of your home, it will cycle more often in an effort to keep up with the demand.
As you can see, there are many reasons why a furnace might kick on and off frequently. If you're experiencing short heating cycles, call a technician, like those at Reed Heating, to come look at your unit right away.