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Proudly Serving The Columbia Area Since 1985

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Proudly Serving The Columbia Area Since 1985


Fulmer Heating & Cooling Blog

Is It Your HVAC System or Your Thermostat?


There are some obvious things that prompt someone to call for HVAC Repair in Columbia, SC. An air conditioner that won’t blow cold air, a heat pump that won’t switch modes, and a heater that won’t power at all are just a few. 

But there are some less-obvious issues that leave homeowners perplexed as to what’s going on. Sometimes the issue isn’t with your HVAC system—it’s the thermostat that’s causing trouble. Here are some examples of when a thermostat is the culprit behind some common—and not-so-common—HVAC issues.

Short Cycling

Short cycling is a common issue with HVAC systems and the easiest fix is when it’s the thermostat acting up. Short cycling is apparent when your HVAC system can’t complete a heating or cooling cycle. It’ll seem like it’s running all day long but your house doesn’t get warm (or cold).

Sometimes short cycling can be caused by a lack of communication between the thermostat and the system. If the thermostat is out of whack, it simply won’t be able to read the actual temperature of your home correctly. 

Higher-Than-Usual Energy Bills

If your utility bill is unusually high and this increase can’t be accounted for through usage, it could be a thermostat issue. When the thermostat can’t read the ambient temperature correctly and thinks it’s warmer or cooler than it actually is, this could result in your HVAC system going into overdrive to try and reach the set temperature. 

The good thing is you should be able to notice when it feels perfectly comfortable in your home but you can hear that the HVAC system is still running. You might be prompted to walk over to the thermostat to determine why it’s still going when it feels so warm/cool in your home. It’s a thermostat issue that needs to be addressed.

The Thermostat Doesn’t Respond to Temperature Changes

If you’ve manually changed the temperature by a few degrees on the thermostat, you should hear your HVAC system turn on. A surefire sign of a thermostat problem is when it doesn’t respond to a change in setting.

HVAC System Won’t Turn On—Or Off

It’s cold in your home and your heater won’t turn on. Or it’s icy cold and the AC keeps blowing cold air. Both of these situations can be attributed to the thermostat’s inability to read the ambient temperature of your home. 

The thermostat is essentially the “brain” behind your HVAC system. If it’s miscalibrated, if a wire is faulty, or if it’s just plain dirty and this is hindering communication, then the thermostat can’t tell the HVAC system what to do.

The Bottom Line

Don’t let an outdated thermostat interfere with your ability to precisely control the temperature of your home. A smart thermostat upgrade will eliminate any thermostat problems, giving you precise temperature control throughout the year. 

Contact Fulmer Heating & Cooling today for HVAC repair in Columbia, SC!

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