You wake up to a cold house on a frigid winter morning. Uh oh. You walk over to your mini split unit to check it out and realize there's a solid block of ice covering the outdoor unit. What's going on here? Why is your mini-split freezing up like this? Don't worry, it happens. Mini-splits work great most of the time, but they can struggle when temps dip into the teens or single digits. In this article, I'll walk you through some common reasons your mini-split might freeze up in winter and give you a few tips to help prevent it from happening again before you buy a new mini split. Stick with The Trade Table, and you'll be cozy and warm in no time.
GREE Vireo+ Ultra 30K BTU 18 SEER Wall Mount Mini-Split Single Zone Heat Pump - VIRU30HP230V1A
$3,917.95
GREE Vireo+ Ultra 30K BTU 18 SEER Wall Mount Mini-Split Single Zone Heat Pump The Vireo+ Ultra combines the design of the original Vireo+ system, while extending the operating capacity to -31°F. It has been designed to blend into any… read more
Common Causes of a Frozen Mini Split
Mini split systems are a popular, efficient way to heat and cool homes, but they can run into issues. One of the most common problems is the unit freezing up, which prevents it from blowing air and doing its job. There are a few reasons why your mini-split may be frosting over. To optimize performance and efficiency for your specific space, consider utilizing a mini split sizing calculator.
Low refrigerant levels
-
The refrigerant in your mini split acts as a coolant, absorbing heat from the air. If refrigerant levels get too low, the unit won't be able to properly cool the air and will frost over. Have an HVAC technician check refrigerant levels and recharge the unit if needed.
Dirty air filter
-
A clogged air filter prevents efficient airflow over the evaporator coil, causing it to freeze. Check your mini split's air filter monthly and replace it every 3 months or if visibly dirty.
-
Remove the air filter by sliding or unscrewing the grill covering the air intake.
-
Note the size and type of your filter to get a proper replacement.
-
Install the new filter with the arrow pointing in the direction of the airflow.
-
Improper defrost settings
-
Mini-splits are designed to go through automatic defrost cycles to melt any frost buildup. If the defrost settings are not properly configured, frost can accumulate. Have an HVAC technician check the unit’s defrost control board and sensors to ensure it's defrosting when needed.
-
The technician can test components like defrost thermostats, defrost timers, and heating elements to determine if any repairs or replacements are required.
-
Outdoor unit airflow blocked
-
If the airflow to the outdoor condenser unit is blocked, it won’t be able to properly release heat and will cause the indoor unit to frost over. Clear away any debris, plants, or other objects within 2 feet of the outdoor unit to improve airflow.
MRCOOL DIY 4th Generation E Star 12k BTU Ductless Mini-Split Heat Pump Complete System 115V/60Hz
$1,738.00
DIY 4th Generation E Star 12k BTU Ductless Mini-Split Heat Pump Complete System 115V/60Hz Introducing the latest in home comfort technology with the 4th Generation MrCool DIY 12K BTU, 22 SEER Ductless Heat Pump System. This powerful single-zone system has… read more
How to Prevent Your Mini Split From Freezing Up
To avoid having your mini split freeze up, there are a few precautions you can take. As temperatures drop, your unit has to work harder to pump refrigerant and circulate air. Give it some help by following these tips:
-
Choose an efficient model rated for very cold weather. Look for a unit specifically designed for low ambient temperatures that can operate in weather as cold as -13°F. More powerful compressors and fans, as well as additional heating components, will allow it to function better in frigid temps.
-
Install it properly. An incorrectly installed unit won’t run efficiently. Make sure it’s placed on a secure, level surface and that all connections are properly sealed and insulated. Insulation helps prevent heat loss, allowing the unit to operate optimally.
-
Increase maintenance. When it’s very cold out, run your mini split for longer periods and have it serviced more frequently. Run it for at least 30 minutes every few hours to prevent the refrigerant from freezing. Schedule maintenance checks every 3-6 months to ensure all parts are working properly and safely. Technicians can recharge refrigerant, check connections, clean coils, and make any necessary repairs or replacements to improve efficiency.
-
Raise the temperature. Bump up the thermostat by a few degrees to account for heat loss in cold weather. A higher set temperature, around 68-72°F, will allow the unit to cycle on more often, preventing the refrigerant and coils from freezing. You can then lower it again once temperatures outside start to rise.
-
Consider a heating booster. For extremely low temperatures, you may need a heating booster or supplemental heating to prevent your mini-split from freezing up. A booster can provide additional heating power, allowing your unit to operate even in very frigid weather. Space heaters, radiators, and other heating methods placed strategically around the area can also help boost the temperature.
MRCOOL E Star DIY 4th Gen 18k BTU Ductless Mini-Split Heat Pump Complete System - 208-230V/60Hz
$2,156.00
E Star DIY 4th Gen 18k BTU Ductless Mini-Split Heat Pump Complete System - 208-230V/60Hz The MrCool 4th Generation DIY 18K BTU, 22 SEER Ductless Heat Pump system offers a complete solution to your home’s heating and cooling needs. This… read more
Tips for Defrosting a Frozen Mini Split
Has your mini split air conditioner been acting up lately? If the unit is frozen over, it likely needs to be defrosted. Don’t worry, defrosting a mini split is quite easy to do yourself. Here are a few tips to get your mini split up and running again in no time.
Turn Off the Power
-
The first step is to turn off the mini-split to avoid any electrical issues while you’re working on the unit. Locate the power switch or breaker for your mini-split and turn it off.
Melt the Ice
-
Once the power is off, you’ll want to melt any built-up ice on the mini-split. You can use a hair dryer, heat gun, or space heater to gently warm the ice until it melts and drips from the unit. Be very careful not to overheat any parts of the mini-split.
Check the Filters
-
While you have the mini split open, it’s a good time to inspect the air filters. Clogged or dirty filters reduce airflow and can lead to freezing. Remove any debris from the filters or replace them if necessary. Clean filters will help prevent future freezing and keep your mini-split running efficiently.
Check for Leaks or Clogs
-
Inspect the refrigerant lines, drains, and vents for any obvious leaks, clogs, or damage that could be causing issues. Have an HVAC technician repair or replace any parts as needed.
Turn the Power Back On
-
Once everything has been checked and the ice has fully melted, you can turn the power for the mini-split back on. Run the unit in fan mode for 10-15 minutes to dry out any remaining moisture before resuming normal operation.
Consider a Service Call
-
If your mini split continues to freeze up frequently after trying these steps, it’s best to have an HVAC professional service your unit. A technician can check for any issues you may have missed and perform necessary repairs or maintenance to get your mini-split running efficiently again.
Buck Cool Mini-Split EZ Connect 24K BTU Complete Installation Kit
$3,012.12
$3,709.99
Buck Cool Mini-Split EZ Connect 24K BTU Complete Installation Kit The Buck Cool Mini-Split EZ Connect Complete Kits are designed to offer a simple solution for your heating and cooling needs. The pre-charged EZ Connect line sets allow for a… read more
Why My Mini Split Freezes Up
So there you have it - a few of the most common reasons why your mini-split may be freezing up, even when it's not that cold outside. Checking the filters, clearing debris, and ensuring proper airflow are all easy DIY troubleshooting steps. But if those don't solve the issue, be sure to call in an HVAC pro. They have the know-how and tools to get your system defrosting and keeping your rooms nice and comfortable again. And that sweet, sweet heat pumping out on demand? That's what these babies are made for. Don't settle for frosty coils or a lukewarm breeze when a tune-up or repair can get that mini split back to doing its thing.
