Summer is right around the corner which means air conditioning and heating contractors can expect an influx of service calls in the near future. Especially during the warmer months, homeowners might notice a dripping sound coming from their unit. The cause may be a frozen evaporator coil which can drastically reduce comfort levels when homeowners need them most. So, why does this happen? To find out, we first need to explore how an air conditioning unit cools a home. The Joule-Thomson effect is a principle in thermodynamics that states that if everything is kept constant, as gas expands and the pressure decreases, the temperature will also decrease. Similarly, if a gas is compressed, the temperature will go up. To explain further, what we perceive as temperature is actually a measurement of energy in molecules. Slow moving molecules feel cold while fast moving molecules feel warm. This same process goes on inside an air conditioning unit. The evaporator coil houses refrigerant which expands inside of it.

In turn, this causes the coil to cool. The unit then blows the unconditioned home air over the cooled coil. The refrigerant then absorbs the heat from the indoor air which is transferred outside the home. Why do Air Conditioners Freeze? Technically, it's the evaporator coil that freezes inside the unit. york ac unit commercialThis coil transfers/evaporates hot air from inside the home and sends it outside. should outside ac unit be levelOne reason for a frozen evaporator coil is airflow restriction. solution air handling unitHomeowners that neglect to change dirty air filters can experience air flow blockage due to clogged filtration. Closing off supply and/or return vents can cause issues with air flow as well. In turn, the cold air accumulates within the unit.

Similarly, insufficient refrigerant or a restriction in the refrigeration system can cause a frozen evaporator coil. Inside the ac unit, refrigerant begins as a liquid, converts into a gas, and then back into a liquid, however the refrigerant level will remain the same. A leak or restriction in the refrigerant line is the likely cause for low refrigerant levels. Another issue that has not been discussed is attempting to cool your home too drastically. If your system is icing up when your thermostat is set below 70, you may be able to solve the problem by simply raising the temperature slightly. A frozen evaporator coil cannot properly transfer heat outside of a home. Condensation forms and essentially, the coil cools itself to the point of freezing. Solutions to a Frozen AC Begin by turning off the unit completely at the thermostat. Do not attempt to thaw the unit by turning the temperature up on the thermostat. Make sure the air conditioning unit is completely turned off.

Inspect the existing air filters and replace them if needed. Also, make sure all registers are unblocked by furniture, drapes, etc. If there is a refrigerant leak, call a professional service contractor. Schedule a service call with a NATE-certified technician to inspect your unit for damage and leaks. The culprit could be one major issue or a combination of small things. Give us a call to inspect your unit before the summer rush starts. Call us at (909) 792-2222 or schedule a service appointment online. Why is My Home Air Conditioner Blowing Warm Air? Back to Blog Page Take advantage of these seasonal offersOne common problem that many homeowners encounter during the colder months is a frozen heat pump. In order to understand why a heat pump freezes, one doesn’t need to be an HVAC expert. Here are some common reasons why a heat pump freezes and what you can do about it. During the summer time and periods of warm weather, a heat pump functions just like any other air conditioning system.

Once the cold weather arrives, the heat pump starts to transfer energy from the outside of your home to the inside by altering the flow of coolant in the system. The energy is used to heat your home when it is cold outside. A heat pump is best suited for temperatures above 32 degrees Fahrenheit. When the temperatures drop below that mark, ice starts to form on the coils, refrigerant lines, and condenser of the unit. Many heat pumps have a defrost option that one can use to help keep freezing from occurring when the temperatures occasionally dip too low. Frequent and prolonged exposure to low temperatures will damage the heat pump and bring about the need for costly repairs or replacement. Freezing is more likely to occur when refrigerant or coolant levels are low. During the fall and winter seasons, it is extremely important for homeowners to be diligent about checking their heat pump’s refrigerant or coolant levels. These levels need to be close to perfect in order to ensure proper operation of the unit when there is extremely cold weather.

Homeowners should hire an HVAC professional to check the refrigerant levels in their heat pump and have them filled when necessary. Sometimes there may be problems with installation that may not arise until the temperatures start to drop. Some problems will reduce the amount of airflow to the pump and cause it to freeze. Other installation problems that can cause a heat pump to freeze are improperly sized coils, refrigerant lines, or even having a heat pump that is too big or too small for the home. An HVAC inspection will confirm if a homeowner has a properly installed heat pump and whether there will be any problems with its operation. Coils that are blocked or dirty will cause a heat pump to work harder, leading to higher energy bills. In many cases, dirt and clogged coils will also affect the efficiency of the heat pump since the motor will eventually burn out much faster. More heat escapes from dirty and clogged coils instead of being transferred into the home to increase comfort.

A heat pump that is not able to drain properly will freeze very quickly as the weather gets colder. To prevent problems with drainage, watch the unit for signs of dripping and leaking. Play close attention to where the moisture and condensation drain too. Make sure that the system is not sitting in any water, snow, or other substances that can interfere with operations. Exposure to freezing rain, snow or cold temperatures for long periods of time will reduce the efficiency of any heat pump will cause it to freeze from the outside and render the unit useless. Make sure that the entire air conditioning system and heat pump are situated on a platform that keeps it from being covered with snow, water and debris. Consider placing the unit under an awning in an area where rainwater will not run off from the roof or drip down into the system. When it comes to heat pumps some freezing is to be expected, however frequent occurrences may be indicative of a problem. Ways to keep a heat pump from freezing include: