Why Is My Heater Short Cycling?

As Boston’s winters get colder, the last thing you want to do is play on-and-off with your heating system. While short cycling is a common problem, especially in New England’s charming older houses, it’s one that needs to be addressed as soon as possible.

Here’s what to know about heater short cycling and how N.E.T.R., Inc. can help you find practical solutions so you can stay warm all winter long.

What Is Short Cycling? 

Heater short cycling occurs when a heating system turns on and off more frequently than necessary to maintain the set temperature. Instead of completing a full heating cycle, the system shuts down prematurely, usually before the thermostat has reached the desired temperature. This rapid cycling can cause serious problems that impact the quality and efficiency of your heating system.

Signs Your Heater Is Short Cycling

If your heater is short cycling, there are several ways to tell, like: 

  • Feeling hot and cold spots throughout your house. Short cycling prevents your heater from distributing warmth evenly throughout your house, leaving cold spots in some places and areas that are too warm in others. 
  • Getting higher than normal energy bills. A sudden increase in your energy bills is always a red flag and you need to investigate. Short cycling makes your heating system inefficient, making it work harder and use more energy to produce the same amount of heat.
  • Hearing the heater shut off before it has completed a full cycle. If you hear your heater turning on and off a lot, this is a clear indicator of short cycling. You might hear clicking sounds as your heating system tries to turn on and immediately shuts itself off. This is most common with gas and central HVAC systems in older Northeast houses.
  • Readjusting the thermostat settings frequently to stay comfortable. If you find yourself constantly readjusting the thermostat settings to stay comfortable, it could be because your heater is cycling on and off too frequently to maintain the right temperature. 

Most Common Causes of Heater Short Cycling

There are many different reasons why your heater could start short cycling, including:

Improper Thermostat Settings

Most electronic thermostats are set to turn your system on or off when the temperature changes by 1.5 degrees or more. If the cycle rate is set lower than this, say at 1 or even 0.5, your system will turn off and back on two to three times more often in the same amount of time. Check this setting and make sure it’s at 1.5. If not, you’ll want to update it.

Loose Wiring

Loose wiring is another common culprit behind thermostat-related short cycling. If your wiring isn’t secure, it can trigger irregular and rapid on-off cycles as the wires jiggle around.

Dirty Air Filters

Dirty or clogged air filters do more than just lower your indoor air quality — they make it harder for your system to operate and can lead to short cycling. Your system has to work harder to distribute the right amount of warm air, causing it to break down faster. This is an easy solution though and you can avoid this problem entirely by checking and replacing your air filters as needed.

Blocked Vents

Like clogged air filters, obstructed or closed vents also create airflow problems and make it more difficult for your heating system to circulate treated air. This can cause your system to overheat and shut off prematurely as a safety measure.

If you have a central HVAC system, make sure all of the vents are open and unobstructed. If you need to move furniture around, make sure it’s not covering up any of your air registers.

The Wrong Size Heating System

If your heating system is too big or too small for the amount of space in your house, this can also lead to short cycling problems. Overcapacity causes your system to reach the temperatures you set very quickly, resulting in the system shutting off early on in its cycle. Then, your home cools down and your system turns back on again, repeating the problem. Undercapacity can also cause short cycling as your heater struggles to meet your thermostat settings.

How a Qualified HVAC Professional Can Help

Working with an experienced HVAC professional is key to diagnosing and repairing problems with your home heating system. At N.E.T.R., Inc., our Mitsubishi Electric Elite Diamond contractors are highly trained to assess even the most complex comfort issues and provide workable solutions that maximize energy efficiency and optimize your value.

Contact us today to learn more or to schedule a home visit from one of our veteran technicians by calling (781) 933-6387. You can also fill out our contact form and we’ll get back to you.