Is Your Thermostat Causing Your AC to Freeze Up in Boone?

It’s another hot summer day in Boone, and you feel like you might melt. Your air conditioner is not doing its job and your and causes your AC to Freeze up.

It’s acting a bit icy.

Seeing frost on your AC unit can be alarming, and you might be scratching your head wondering what went wrong. While several culprits can lead to a frozen AC, one often-overlooked offender might be lurking right on your wall:

Your thermostat.

Our team at Neighbors Heating and Cooling created this blog to unravel the chilly world of AC freeze-ups, explaining what they are, how they impact your comfort, and how a bad thermostat can be the surprising reason behind it.

Here’s a quick rundown of what we’ll cover:

1. What is an AC Freeze-Up, and Why Does it Matter?
2. Understanding the Common Causes of AC Freeze-Ups
3. How Does a Thermostat Actually Work?
4. When Good Thermostats Go Bad
5. Solutions and Prevention Tips.

1. What is an AC Freeze-Up, and Why Does it Matter?

Your air conditioner is a tireless workhorse, diligently pulling warm, humid air from your Boone, home and replacing it with cool, refreshing comfort. At the heart of this process is the evaporator coil, located inside your indoor unit. This coil contains cold refrigerant that absorbs heat from the air blowing across it.

An AC freeze-up occurs when this evaporator coil gets too cold and moisture in the air freezes onto its surface, forming ice. Think of it like frost building up on your freezer coils, but on a much larger and more problematic scale.

This layer of ice acts like an insulator, preventing the coil from effectively absorbing heat. As a result, your AC unit has to work harder and longer to cool your home, leading to:

• Reduced or No Cold Air: This is the most immediate and frustrating consequence. The icy barrier hinders heat exchange, leaving you with lukewarm or no cool air blowing from your vents.
• Increased Energy Bills: Your struggling AC unit consumes more energy trying to overcome the ice, leading to a noticeable spike in your electricity costs.
• Potential System Damage: If left unaddressed, a persistent freeze-up can put undue stress on other components of your AC system, potentially leading to costly repairs or even premature failure.

You can trust Neighbors Heating and Cooling to quickly diagnose any issues with your AC and recommend a practical repair plan. Making customers happy is what we do best!

2. Understanding the Common Causes of AC Freeze-Ups

While the visual of ice is the obvious symptom, the underlying causes of an AC freeze-up can vary. Here are some of the most common culprits:

• Poor Airflow: This is often the number one offender. If the warm air from your home can’t circulate properly across the evaporator coil, the coil gets too cold and freezes. A dirty air filter is a prime suspect here, restricting airflow like a clogged artery.
• Low Refrigerant: Refrigerant is the lifeblood of your AC system, responsible for absorbing and releasing heat. When refrigerant levels are low (usually due to a leak), the pressure in the system drops, causing the evaporator coil to become excessively cold and freeze.
• Mechanical Issues: A malfunctioning blower motor can prevent proper airflow even with a clean filter. Dirty coils can also hinder heat transfer, making the evaporator coil colder than it should be. A stuck contactor in the outdoor unit might cause it to run continuously, even when the indoor unit isn’t calling for cooling, leading to freezing.
• A Bad Thermostat: Yes, that unassuming device on your wall can be a major instigator of AC freeze-ups! A faulty thermostat might not be sending the correct signals to your AC unit, causing it to run longer than necessary or even continuously. This issue can cool the evaporator coil to the point of freezing, especially on cooler nights or less humid days.

3. How Does a Thermostat Actually Work?

To understand how a bad thermostat can cause problems, it’s helpful to know how a healthy one operates. Think of your thermostat as the command center for your HVAC system.

It senses the temperature in your home and tells your furnace or air conditioner when to turn on or off to maintain your desired setting.

Most modern thermostats use sensors to measure the ambient temperature. When the temperature deviates from your setpoint, the thermostat sends an electrical signal to your HVAC unit. For cooling, when the room temperature rises above your set temperature, the thermostat signals the AC to turn on.

It continues to run until the room temperature drops to the desired level, at which point the thermostat signals it to shut off.

More advanced smart thermostats can learn your preferences, adjust automatically based on schedules or occupancy, and even provide energy usage insights. However, the fundamental principle remains the same: sensing temperature and signaling the HVAC system to respond accurately.

4. When Good Thermostats Go Bad

Now, let’s connect the dots and see how a bad thermostat can lead to your AC turning into an ice machine:

• Inaccurate Temperature Readings: If your thermostat’s temperature sensor is malfunctioning, it might be reporting a temperature that’s significantly higher than the actual room temperature. This will cause your AC to run for much longer than needed, potentially overcooling the evaporator coil and leading to a freeze-up.
• Stuck Relays or Switches: Inside your thermostat are electrical components (relays or switches) that open and close to send signals to your AC. If these components become stuck in the “on” position, your AC might continue to run even after the desired temperature is reached. This issue is particularly common with older, mechanical thermostats.
• Incorrect Wiring: If your thermostat was recently installed or if there’s been any electrical work, incorrect wiring can send faulty signals to your AC unit, causing it to run erratically or continuously.

5. Solutions and Prevention Tips

If you suspect your AC is frozen, the first crucial step is to turn off your system immediately. Running a frozen AC can cause further damage.

Allow several hours for the ice to melt completely. Don’t just change the filter and turn it back on; the ice inside the evaporator coil might still be substantial.

Once the unit has thawed, you can try to identify the cause. Here’s a breakdown of solutions and prevention tips:

AC Frozen Solutions:

• Check and Replace Your Air Filter: This is the easiest and often the first fix. A dirty filter restricts airflow, so replace it with a clean one (aim for every 1-3 months, especially during peak cooling season).
• Ensure Proper Airflow: Make sure your vents are open and not blocked by furniture or other objects.
• Address Low Refrigerant: This requires a professional HVAC technician. Do not attempt to add refrigerant yourself. A Neighbors Heating and Cooling technician can identify and repair any leaks and recharge your system.
• Repair Mechanical Issues: If you suspect a faulty blower motor, dirty coils, or a stuck contactor, call a qualified HVAC technician for diagnosis and repair.
• Troubleshoot Your Thermostat:
  • Check the Batteries: If you have a battery-powered thermostat, try replacing the batteries.
  • Inspect Wiring: If you’re comfortable and know what you’re doing, visually inspect the wiring connections. Loose or incorrect wiring can cause issues. However, if you’re unsure, it’s always best to call us.
  • Consider Replacement: If your thermostat is old, malfunctioning, or constantly causing issues, it might be time for a replacement. A modern, properly functioning thermostat can improve efficiency and prevent future freeze-ups.

Stop searching, “Why is my AC freezing up?” Give Neighbors Heating and Cooling a call, and we can quickly assess the situation and recommend a practical solution that fits your budget!

AC Freeze Prevention Tips:

• Annual HVAC Maintenance: Schedule yearly checkups with Neighbors Heating and Cooling. May and June are perfect months for a preseason AC tune-up. Our qualified HVAC technicians can inspect your system for potential problems like low refrigerant, dirty coils, and worn-out components, catching issues before they lead to a freeze-up. They can also check the calibration and proper functioning of your thermostat.
• Avoid Setting Your Thermostat Too Low: While it’s tempting to blast the AC on a scorching day, setting it too low (especially below 68 degrees) can sometimes cause the evaporator coil to over-cool and freeze, particularly on humid days.
• Ensure Proper Ventilation: Good airflow throughout your home helps your AC system operate efficiently.

Call for AC Repairs and Maintenance

If you suspect your thermostat or any other component is causing your AC to freeze up, don’t hesitate to call Neighbors Heating and Cooling at 515-232-7777 or request service online for expert diagnosis and reliable solutions. We care for homes and businesses in Boone, IA, and throughout the greater Boone County region.