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Serving the Greater New Braunfels, TX Area

Serving the Greater New Braunfels, TX Area


Why Does My Furnace Turn On and Off So Often?


During our mild winter months when you run the furnace to keep your household warm, you’ll become used to a standard pattern for how the HVAC system turns on and off. You’ll hear the blower fan come on, then the furnace burners ignite, and the rush of heated air pushed through the ductwork. After fifteen minutes or more, the furnace will then start cycling down, turning off the burners and eventually the fan. When the temperature begins to fall below the setting on the thermostat, the HVAC system will begin another heating cycle.

This is the normal behavior you’re used to from the furnace and probably don’t pay much attention to it. But if the furnace breaks this pattern and begins to turn on and off with greater frequency, you may notice. And then you may wonder: is this a problem?

Yes, it is. It’s called “short-cycling”

The name for this phenomenon with a furnace (which can occur with other types of heating systems as well as air conditioners) is short-cycling. The furnace is not completing its full heating cycle, instead shutting down early and restarting a short time later. You may hear the furnace run for only ten minutes or less before shutting down, and only a few minutes before it starts again. This can result in the furnace going through abortive cycles multiple times per hour.

Why this is a problem

You might be able to guess why short-cycling isn’t something you want happening to your furnace. All that on-and-off sounds like it drains a lot of energy … and you’re 100% right. A furnace draws on the most power when it starts up, and when it is starting up twice more than it should, that adds up to an immense amount of energy waste. It’s something you’ll soon start to see on your utility bills.

Along with wasting power, this constant starting and stopping puts wear on the furnace’s components. Stress on the blower motor, strain on gas valves, extra use of the ignition system, etc. This causes the furnace to age faster. You can expect a short-cycling furnace to soon need repairs. In the long-term, it will cut short the furnace’s service life.

Finally, short-cycling means poorer heating. The furnace isn’t staying on long enough to distribute the amount of heat necessary to reach the thermostat setting. The rooms in the center of the house may warm up to the desired temperature, but other rooms may be left lukewarm or cold.

Why this happens

There are many possible sources for short-cycling. It might be as simple as a clogged air filter; we always recommend checking on the filter to see if it needs to be swapped for a clean one. It might be a problem in the control board, a miscalibrated thermostat, leaks in the ductwork, a malfunctioning limit switch, or even a furnace that was installed incorrectly so it’s too large for the space it’s supposed to heat.

But what you need to know is that it takes professional furnace service in New Braunfels, TX to locate the source of the short-cycling and have it fixed. We’re only a phone call away to handle this problem!

Call on Thayer Air Conditioning to schedule top-quality service to care for your furnace. Your comfort is our #1 priority!

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