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Why does my thermostat say aux heat? the chilling truth revealed

Rob is a seasoned home improvement writer with over 15 years of experience researching and recommending products for the home. Prior to starting Nurturing Homeaid, he wrote extensively for This Old House magazine and has been featured as a home expert on several TV and radio programs. An avid DIY-er,...

What To Know

  • Auxiliary heat is a supplementary heating source that kicks in when your primary heating system struggles to maintain your desired temperature.
  • This usually happens during extreme cold snaps or when the thermostat is set to a higher temperature than the primary system can handle.
  • This can lead to the activation of auxiliary heat as the system struggles to maintain the desired temperature.

When the mercury dips and the cold seeps into our homes, our thermostats become our trusted companions, keeping us warm and cozy. However, occasional cryptic messages can leave us scratching our heads. One such enigma is the enigmatic “Aux Heat” display. Let’s delve into the depths of this heating mystery and uncover the reasons why your thermostat might be declaring “Aux Heat.”

Understanding Auxiliary Heat

Auxiliary heat is a supplementary heating source that kicks in when your primary heating system struggles to maintain your desired temperature. This usually happens during extreme cold snaps or when the thermostat is set to a higher temperature than the primary system can handle.

Why Your Thermostat Might Say Aux Heat

There are several reasons why your thermostat may be triggering auxiliary heat:

1. Extreme Cold Temperatures

When outdoor temperatures plunge to extreme lows, your primary heating system may not be able to generate enough heat to keep up with the demand. In such cases, your thermostat switches to auxiliary heat to provide additional warmth.

2. Oversized or Undersized Heating System

An oversized heating system may cycle on and off too frequently, resulting in temperature fluctuations. Conversely, an undersized system may struggle to maintain the desired temperature, leading to the activation of auxiliary heat.

3. High Thermostat Setting

If you set your thermostat to a significantly higher temperature than normal, your primary heating system may not be able to keep up. This triggers auxiliary heat to bridge the temperature gap.

4. Faulty Thermostat or Sensors

A malfunctioning thermostat or faulty temperature sensors can also cause the “Aux Heat” message to appear. These components are responsible for accurately measuring the temperature and controlling the heating system.

5. Frozen Condenser Coil (Heat Pump Systems)

If you have a heat pump system, a frozen condenser coil can prevent the primary heating system from operating efficiently. This triggers auxiliary heat to compensate for the loss of heating capacity.

6. Dirty Air Filter

A dirty air filter can restrict airflow through the heating system, reducing its efficiency. This can lead to the activation of auxiliary heat as the system struggles to maintain the desired temperature.

7. Low Refrigerant Levels (Heat Pump Systems)

Low refrigerant levels in a heat pump system can also result in the “Aux Heat” message. Refrigerant is essential for the heat transfer process, and low levels can impair the system’s ability to generate heat.

Steps to Address “Aux Heat”

If your thermostat is displaying “Aux Heat,” there are a few steps you can take:

  • Check the outdoor temperature. If it’s extremely cold, auxiliary heat may be necessary.
  • Ensure that your heating system is properly sized and functioning correctly.
  • Avoid setting the thermostat to excessively high temperatures.
  • Replace the air filter regularly.
  • Schedule maintenance for your heat pump system to prevent frozen condenser coils or low refrigerant levels.
  • If the problem persists or you suspect a faulty thermostat or sensors, contact a qualified HVAC technician for assistance.

When to Worry

While auxiliary heat is typically a temporary measure to supplement your primary heating system, prolonged use can indicate an underlying issue. If your thermostat frequently displays “Aux Heat,” it’s advisable to have your heating system inspected by a professional to identify and resolve any potential problems.

Key Points: Unlocking the Secrets of Aux Heat

Understanding the reasons behind the “Aux Heat” message on your thermostat empowers you to make informed decisions about your heating system. By addressing the underlying causes and maintaining your equipment properly, you can ensure a warm and comfortable indoor environment even during the coldest winter days.

Frequently Asked Questions

Q: Is it okay to use auxiliary heat for extended periods?

A: While auxiliary heat can provide temporary relief during extreme cold, prolonged use can be inefficient and costly. It’s best to address the underlying issue causing the need for auxiliary heat.

Q: How do I know if my thermostat or sensors are faulty?

A: Signs of faulty thermostat or sensors include inaccurate temperature readings, erratic heating behavior, and persistent “Aux Heat” messages.

Q: What are the benefits of regular HVAC maintenance?

A: Regular maintenance helps prevent system breakdowns, improves efficiency, reduces energy bills, and extends the lifespan of your heating equipment.

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Rob Sanders

Rob is a seasoned home improvement writer with over 15 years of experience researching and recommending products for the home. Prior to starting Nurturing Homeaid, he wrote extensively for This Old House magazine and has been featured as a home expert on several TV and radio programs. An avid DIY-er, Rob takes pride in testing out the latest tools and gadgets to see how they can make home projects easier. When it comes to heating systems, he's evaluated over 50 different furnace and boiler models over the years. Rob founded Nurturing Homeaid with his business partner Jim in 2020 to provide homeowners with genuine product recommendations they can trust. In his free time, Rob enjoys remodeling old homes with his family and traveling to visit architectural landmarks across the country. He holds a bachelor's degree in Journalism from Syracuse University.
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