What causes a brand-new AC unit to freeze up?

A brand-new AC unit can freeze up due to factors such as operating in cold temperatures, poor airflow from dirty filters, dirty coils, low refrigerant levels, or issues with the defrost cycle.

How can I prevent my new AC unit from freezing up?

To prevent freezing, avoid operating the AC in temperatures below 60°F, maintain clean air filters, regularly clean the coils, ensure proper refrigerant levels, and verify the defrost cycle is functioning correctly.

Is it normal for a new AC unit to freeze up?

No, it is not normal for a new AC unit to freeze up. If freezing occurs, it indicates an underlying issue that should be addressed promptly.

Can dirty air filters cause my new AC unit to freeze up?

Yes, dirty air filters can restrict airflow, leading to freezing. Regularly cleaning or replacing filters helps maintain proper airflow and prevents freezing.

Should I operate my new AC unit in temperatures below 60°F?

No, operating your AC unit in temperatures below 60°F can increase the likelihood of freezing. It's advisable to turn off the AC and open windows to let in cool air when it's too cold outside.

Why Is My Brand-New AC Unit Freezing Up?

Premier Systems

January 11, 2023

It is undeniably frustrating to invest hundreds or thousands of dollars in a cooling system only to end up wondering, "Why is my brand-new AC unit freezing up?" The answer could be a straightforward problem with a simple solution or something more complicated. The only way to be sure is to call in a professional technician such as Premier Systems, the AC repair experts in Bozeman, MT.

How a Typical AC System or Heat Pump Manages Heat and Cold

The first step to understanding potential answers to the question, "Why is my brand-new AC unit freezing up" is understanding what happens when your AC works normally.

The primary function of an air conditioner is to deliver cool air throughout the house. A typical air conditioner cools the air by drawing heat out of the air inside the house and moving the heated air outside. In a central air system, the evaporator coils in the indoor unit take heat from the air, and the condenser coils release it into the air outside.

Refrigerant is key to this transfer process. Liquid refrigerant in the evaporator coils absorbs heat when it becomes a gas. The refrigerant then releases its heat when it turns back into a liquid. Any AC problem that interferes with this process can potentially lead to overheating or freezing.

How Can I Tell That My AC Unit Is Freezing Up?

A symptom of a frozen AC unit is that the vents in your air conditioning system will produce warm air because the coils lose their ability to transfer heat. Your AC system might run continuously or longer than it usually does because the thermostat detects that the AC system has not succeeded in reducing the room temperature.

If frozen coils are the result of clogged filters and poor airflow, you might notice that your air vents release a trickle of tepid air rather than a powerful blast of air. Addressing the cause of the frozen AC coils will restore power and vitality to your air conditioning system.

Is It Normal for Air Conditioning Units to Freeze Up?

Your air conditioner's coils should not freeze during normal operation since the evaporator coils should have continuous exposure to warm air inside your home. The outdoor condenser coils should not freeze because they should heat up when the compressor applies pressure to the refrigerant.

Causes of Frozen Coils

Why is my brand-new AC unit freezing up? A faulty installation is one reason they could fail.

Proper maintenance and judicious use of the air conditioner can improve the performance of your air conditioner and prevent them from occurring, but the following conditions also increase the risk of frozen coils:

Cold Temperatures

If you run your air conditioner when outdoor temperatures are too low, you can increase the likelihood of your AC system freezing up. If the temperature outside is below 60 degrees, turn off the AC and open the windows to let in cool air.

In general, it is a good idea to set your air conditioner to a temperature at or above 78 degrees Fahrenheit or higher if you are not at home. Reducing the work that the AC has to do reduces wear and can prevent problems like frozen coils.

Poor Airflow

Naturally, your air conditioner requires exposure to the air inside and outside your home for the air conditioning to work. If air cannot get to the evaporator or condenser coils, the cycle of heat transfer will not take place.

For example, if the refrigerant inside the evaporator coils cannot absorb heat from the air, it might draw heat from the pipes instead, causing the pipes to freeze up.

A dirty air filter is one cause of poor airflow. When the filter becomes clogged, air cannot move as easily through the ductwork.

Dirty Coils

Dirty coils can cause an AC unit to freeze up because the layer of dirt can insulate the coils against the air temperature. If they are dirty, cleaning them could solve the problem of your AC unit freezing. However, the buildup of ice on your AC unit could damage the coils.

Low Refrigerant Levels

You might think that low refrigerant levels would lead to a less pronounced temperature change in the coils. However, if the coils have insufficient refrigerant, the remaining refrigerant can expand too quickly in the evaporation coils, cooling down too quickly and leading to the formation of ice on the coils.

Problems with the Defrost Cycle

The evaporator coils in an AC system will naturally get cold as it converts liquid refrigerant into gas. Before you have a chance to worry, "Why is my brand-new AC unit freezing up?" the AC defrost cycle should kick in. The defrost cycle runs the compressor without running the fan, causing the condenser coils to heat up.

The defrost cycle typically takes about 10 minutes. If the defrost cycle takes longer or your AC system enters the defrost cycle more frequently than about once every half hour, there might be a problem with the temperature sensor, or the defrost cycle might be ineffectual.

If the thermostat or temperature sensors on your air conditioning unit malfunction, your AC might fail to enter the defrost cycle when the coils get too cold. When this happens, a professional can identify and replace the faulty component. Depending on the manufacturer and model of your air conditioner, your thermostat display might show an error message and prompt you to make a service appointment.

Why It Is Bad For Your AC Unit to Freeze Up?

A frozen AC system will not cool air efficiently, so you will need to fix the issue to keep your home at a desirable temperature in the summer. Ice can damage frozen AC coils, further reducing the efficiency of your AC system. The ice can form a barrier between the air and the coils, interfering with heat transfer.

You might think that ice around the coils will make it easier for them to keep the air cool, but the reality is more complex. Ice can actually be an insulator, especially if the ice retains pockets of air. Like ice buildup in your freezer, ice on AC coils reduces the overall efficiency of the appliance.

How To Keep Your AC System from Freezing Up

Regular maintenance and good AC usage habits are the best ways to reduce the likelihood of your AC system freezing up in the future.

Watch out for any warning messages or alerts on your HVAC thermostat.
Keep the indoor and outdoor AC units clean and free from debris.
Save money and reduce wear on your system by keeping your AC off when it is cool outside.
Schedule regular AC tune-ups each fall.

The best way to reduce the chance of frozen AC coils is to find an experienced maintenance technician and let them know as soon as possible whenever your AC has any issues.

For a Smoothly Running AC Unit in Bozeman, MT, Call Premier Systems

The dedicated and talented team at Premier Systems is ready to help if your AC unit in Bozeman, MT acts up. We can recognize the signs you need AC repair and give you many repair, upgrade, or replacement options, including refrigerant leak repair, coil cleaning, and thermostat repair.

Don't let ice buildup lead to high air conditioning repair bills. If you are wondering, "Why is my brand-new AC unit freezing up?" call Premier Systems at 406-380-3083 to speak with an experienced technician and set up a service appointment today.

< Older Post

Newer Post >

HVAC Problems Homeowners Notice During Montana's Rainy Days

June 1, 2026

5 HVAC Problems Homeowners Notice During Montana's Rainy Days Rainy weather can be a welcome break from the summer heat, but it can also reveal hidden issues with your home's heating and cooling system. Increased humidity, fluctuating temperatures, and excess moisture can all impact your HVAC system's performance. If you've noticed your home feeling less comfortable during rainy weather, your HVAC system may be trying to tell you something. Here are five common HVAC problems homeowners experience during Montana's rainy days and what you can do about them. 1. Excess Indoor Humidity One of the most common complaints during rainy weather is a home that feels damp or sticky, even with the air conditioner running. Your HVAC system does more than cool the air—it also removes moisture. If your system isn't properly dehumidifying your home, indoor humidity levels can rise quickly. Signs of High Indoor Humidity: Sticky or clammy indoor air Condensation on windows Musty odors Increased allergy symptoms If your home consistently feels humid, your air conditioner may need maintenance or your system may be improperly sized for your home. 2. Musty Smells Coming from Vents Rain and humidity create the perfect environment for mold and mildew growth. If you notice a musty odor when your HVAC system turns on, moisture may be collecting somewhere in the system. Common causes include: Dirty evaporator coils Clogged condensate drains Mold growth in ductwork Excess moisture around the air handler Ignoring these odors can lead to reduced indoor air quality and potential health concerns for your family. 3. Reduced Airflow Rainy weather can expose airflow issues that may have gone unnoticed during drier conditions. Dirty air filters, clogged coils, or ductwork problems can restrict airflow and make it harder for your system to maintain comfortable temperatures. Watch for: Weak airflow from vents Rooms that won't cool evenly Longer run times Higher energy bills A professional HVAC inspection can quickly identify and resolve airflow problems before they become major repairs. 4. Water Leaks Around Your HVAC Equipment Many homeowners are surprised to find water pooling near their indoor HVAC unit during rainy periods. While it may seem like rainwater is entering the system, the issue is often related to a clogged condensate drain line. Your air conditioner removes moisture from the air, and that water needs somewhere to go. When drain lines become blocked, water can back up and leak around your equipment. Don't ignore water around your HVAC system. Left untreated, it can damage flooring, walls, and even the unit itself. 5. Thermostat and Electrical Issues Heavy rainstorms can sometimes cause power fluctuations that affect HVAC controls. If your thermostat isn't responding properly or your system cycles on and off unexpectedly after a storm, electrical components may have been affected. Common warning signs include: Blank thermostat screens Inconsistent temperatures System short cycling Failure to start If you notice these symptoms after severe weather, it's best to have a technician inspect the system to prevent further damage. Keep Your HVAC System Ready for Any Weather Montana's weather can change quickly, and your HVAC system needs to be ready for everything from summer rainstorms to humid days and temperature swings. Regular maintenance helps identify small problems before they become expensive repairs. A seasonal HVAC tune-up can: Improve system efficiency Reduce humidity issues Prevent unexpected breakdowns Extend equipment life Improve indoor air quality Schedule Your HVAC Inspection Today If you've noticed musty odors, humidity problems, weak airflow, or water leaks during recent rainy weather, don't wait for the problem to get worse. Our experienced technicians can diagnose the issue and help keep your home comfortable no matter what the forecast brings. Contact us today to schedule your HVAC inspection and ensure your system is ready for Montana's changing weather.

Why Your House Feels Humid Even With the AC Running

May 26, 2026

Why Your House Feels Humid Even With the AC Running

5 Signs Your AC Won’t Survive the Summer

May 20, 2026

5 Signs Your AC Won’t Survive the Summer

Why Spring Is the Best Time to Replace Your Air Conditioner in Montana

May 11, 2026

Why Spring Is the Best Time to Replace Your A/C

How to Keep Your Indoor Air Clean When Wildfire Smoke Is in the Air

April 28, 2026

Wildfire season has become an increasingly common part of life in Southwest Montana, especially for homeowners in Bozeman, Belgrade, and Four Corners. While the smoky haze outside is easy to see, what’s happening inside your home is often less obvious. Many people assume that simply closing windows and doors will keep them safe—but wildfire smoke can still enter your home and impact your indoor air quality (IAQ) in ways that affect both comfort and health. Why Wildfire Smoke Indoors Is a Serious IAQ Concern Wildfire smoke is made up of extremely fine particles called PM2.5, which are small enough to pass through tiny openings and even some standard HVAC filters. Once inside your home, these particles can circulate through your ductwork and linger in the air. For homeowners in our area, poor indoor air quality during wildfire season can lead to: Coughing, sneezing, and throat irritation Headaches and fatigue Aggravated asthma or allergies Increased strain on your HVAC system Without proper filtration and system maintenance, your home’s air may not be as clean as you think. How Smoke Affects Your HVAC System Your HVAC system plays a major role in managing your indoor air quality —especially during wildfire events. When smoke enters your home, your system can either help remove harmful particles or unintentionally spread them throughout your space. If your system isn’t equipped with the right components, you may experience: Reduced filtration of fine smoke particles Dirty ductwork circulating contaminants Increased wear and tear on system components Decreased efficiency and airflow This is why homeowners across Bozeman and Belgrade are upgrading their systems to better handle wildfire smoke conditions. HVAC Solutions to Improve Indoor Air Quality During Wildfire Season The most effective way to protect your home’s air is through professional HVAC solutions designed specifically for indoor air quality in Four Corners, Belgrade, and Bozeman. Upgrade to HEPA or High-Efficiency Filters Standard filters aren’t designed to capture the smallest smoke particles. Upgrading to HEPA filters or high-MERV rated filters allows your system to trap significantly more airborne contaminants, improving your IAQ immediately. Install Whole-Home Air Purification Systems Advanced air purification systems integrate directly into your HVAC system to continuously clean the air as it circulates. These systems are especially effective during wildfire season when outdoor air quality is poor for extended periods. Add an Air Scrubber Air scrubbers go beyond traditional filtration by actively removing pollutants, odors, and particles from the air and surfaces in your home. This added layer of protection can make a noticeable difference in homes affected by wildfire smoke. Schedule Professional Duct Cleaning If smoke has entered your home, particles can settle inside your ductwork. Duct cleaning removes built-up contaminants and prevents them from being recirculated, helping restore cleaner air throughout your home. Keep Up with HVAC Tune-Ups Regular HVAC tune-ups ensure your system is running efficiently and filtering air properly. During wildfire season, a well-maintained system is critical for maintaining healthy indoor air quality. Long-Term Protection for Homes in Bozeman, Belgrade & Four Corners Wildfire smoke isn’t just a temporary inconvenience—it’s an ongoing challenge for homeowners in Southwest Montana. Investing in indoor air quality solutions through your HVAC system provides long-term protection for your home and your family. By combining: High-efficiency filtration Whole-home air purification Air scrubbers Clean ductwork Routine system maintenance …you can significantly reduce the impact of wildfire smoke indoors. Breathe Easier with the Right HVAC Support Your home should be a place where you can escape poor outdoor air—not bring it inside. With the right HVAC upgrades and maintenance, you can take control of your indoor air quality in Bozeman, Belgrade, and Four Corners, even during the peak of wildfire season. If you’re noticing smoke lingering in your home or want to prepare ahead of time, working with a trusted HVAC professional can help you choose the best solutions for cleaner, healthier air. Cleaner indoor air starts with the right system—and the right team behind it.