What Are the Signs of a Faulty Thermostat?

HVAC Logo IconBy Tom MoorJune 12, 2024
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Fixing a Bad Thermostat Could Require Professional Help

Think of your home’s thermostat as the brain of your HVAC system. When it acts up, your air conditioner or furnace won’t function properly either, leaving you in a bind. Spotting the signs of a faulty thermostat is key to quickly resolving issues and restoring comfort to your home.

Signs of a Faulty Thermostat

Look out for the following signs your thermostat is malfunctioning:

Short Cycling

Does your HVAC system turn on, shut down after a few minutes, then start back up without ever completing a full cycle? This is called short cycling, which is usually caused by a faulty thermostat sensor, an issue with the unit’s wiring, or a malfunction within the HVAC system itself. An HVAC contractor can inspect the thermostat and recommend either a repair or a new thermostat depending on the severity of the problem.

Wonky Temperature Readings

Does your temperature read 72 degrees, but it feels like it’s a sauna inside? Inaccurate temperature readings are another sign of a faulty thermostat, typically caused by old age, a failing sensor, or the need for calibration.

Incorrect thermostat readings can cause the HVAC system to start or stop at inappropriate times, causing comfort issues throughout the home and higher energy costs. You can check for inaccurate readings by comparing the temperature on the thermostat with that of a nearby thermometer. If the temperatures are off, consider replacing your thermostat.

The Silent Treatment

When you adjust your thermostat, you should hear a click and the sound of your HVAC system turning on within a few seconds. If the thermostat isn’t responding to any of your commands, it may indicate damaged wiring or a broken internal component.

High Energy Bills

If your electricity bills are going through the roof without any corresponding weather patterns, it could signal a problem with either your HVAC system or thermostat. A faulty thermostat may inaccurately regulate the HVAC system, resulting in excessive heating or cooling and increased energy consumption.

How to Fix a Malfunctioning Thermostat

To troubleshoot a faulty thermostat, start by performing a few basic DIY steps. This may include checking for any wiring issues, cleaning the thermostat, and replacing the batteries.

If these steps don’t work, contact an HVAC professional. They can inspect the thermostat, accurately diagnose the issue, and determine whether it needs repaired or replaced.

Generally, if the thermostat is relatively new and the issue seems minor, a repair may work fine. However, if it’s an older thermostat and you’re dealing with comfort issues, it’s probably more cost-effective in the long run to install a new thermostat to ensure reliable performance and energy efficiency.

Thermostats last about 10 years on average. Factors such as the type of thermostat, its brand and quality, usage, and maintenance can all factor into its lifespan.

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