There is nothing more frustrating than a failing air conditioner on a very hot and humid day. When an AC is not blowing cold air, it leaves homeowners puzzled, and wanting to resolve the issue as soon as possible. This is especially true nowadays when extreme heat waves in the summer are a norm instead of an exception.
So, what are the possible reasons why an AC would suddenly stop blowing cold air? This write-up will round up the most common causes why air conditioning will suddenly stop cooling the whole house. While some of the issues are easy to deal with even by the homeowner himself, some require professional servicing from an HVAC technician.
How Does It Work – Central AC System
To better understand the explanations of why an AC would suddenly stop blowing cold air, it is a good idea to get a good grasp of how central air conditioning works.
Like other types of air conditioning units, central air conditioners have evaporator coils that absorb the heat inside various areas of the house. The refrigerant, or the liquid chemical responsible for cooling the air, then passes over the coils and becomes an ice-like gas. The AC blower then fans air into the cooling coils, and this cooled air becomes pushed through the various HVAC ducts inside the house, cooling it for everyone’s comfort.
As for the hot air that was absorbed in the room, the gas form of the refrigerant then carries these out of the house through the condenser coils which are in turn installed outdoors. As long as every mechanism is in good working condition, this cycle will just continue until the next maintenance work is due, or when something suddenly goes wrong.
Here are some of the reasons why an AC would suddenly stop blowing cold air:
1. Clogged Air Conditioning Filters
One of the responsibilities of a homeowner when it comes to maintaining his AC unit is to make sure that the filters are replaced or washed regularly. How regular is regular? This depends on the type of filter used, and the manufacturer’s instructions that can be found in the owner’s manual. Being diligent in this area is crucial in keeping a well-maintained air conditioner.
Clogged or dirty filters give the air condition blower a hard time pushing cold air through the various vents in the house. Apart from dust, lint, hair, and pollen building up into the AC filter through time, and so it is crucial to keep an AC maintenance routine. When airflow is hampered, this could consequently prompt the AC to shut down and stop blowing cold air.
Besides, when the mechanism is strained due to the clogged filters, AC parts and systems are more likely to wear out much faster. It can even affect major AC mechanisms like the evaporator and condenser which both are more complicated and expensive to repair.
Usually, filters are replaced quarterly. Homeowners can easily replace or clean indoor filters. All they have to do is to refer to the owner’s manual of their AC for instructions. For first-time homeowners who are unsure how to go about cleaning and replacing AC filters, it is best to get in touch with an HVAC technician who can help and answer questions.
2. Leaking or Low Refrigerant (R22 or R410A)
Refrigerant is the chemical that allows the AC to blow cold air. Without it, humidity levels will increase inside the home. Sometimes the AC runs out of refrigerant either due to continued usage or due to a leak in the system. Either way, if there is none left, the AC cannot blow cold air anymore.
While a homeowner cannot determine a leak or low levels of refrigerant, he can rule out other reasons why his AC is not blowing cold air. Upon coming up with a hunch about low refrigerant levels he can then consult an AC professional to have the unit inspected. Once confirmed, the aircon technician can perform a repair on the leak or replenish the refrigerant supply.
3. Clogged or Blocked Air Register Vents & Ducts
Sometimes, the AC filters may not be clogged but the air registers are. Clogs in either the return or supply vents could prevent the air conditioner from blowing cold air into the house. Some problems in the ductwork will also ultimately lead to a lack of cold air. For instance, if there are blockages within the ducts or problems such as pest infestation could also affect airflow towards the vents.
It is also possible that the vents are accidentally closed or blocked within the house. To rule this out, homeowners should check if every room at home is hot. If only one area seems hot then it is possible that the vent there is blocked, or the ductwork leading to that room is problematic. Ensure that the supply vents around the house are fully opened to fully maximize the home’s AC. If this move still fails, then most likely there is another reason why the HVAC is not blowing cold air.
4. AC not blowing cold could be a problem with the thermostat
Another issue that a homeowner can rule out wheneer the AC fails to blow cold air is a problem with the thermostat. Sometimes, someone at home accidentally sets the thermostat wrong, or sometimes its batteries fail and so it fails to do its function. Check the thermostat first before calling in the pros. It could have been set to heat the house instead of cool it. The batteries may also need to be replaced. If all else fails, then it is high time to call in a technician.
5. An issue with either the condenser or evaporator coil
Condenser and evaporator coils can also fail over time. For instance, since evaporators are almost always moist, it is possible that molds and mildews may set in and prevent it from optimally functioning. The same goes for the condenser. When the AC runs out of refrigerant, the coils can get frozen and cause the AC to malfunction too.
The condenser on the other hand can also get worn out through years of use. If the AC fails even if the registers and filters are unclogged, the refrigerant is topped up, and the evaporator is functioning normally then the condenser may have some issues. Get in touch with an AC technician who can confirm and repair the issue right away.
6. Proper maintenance helps to keep your AC blowing cold air
To keep AC issues at bay, homeowners should make it a point to keep their HVAC Units well maintained. There are maintenance chores that homeowners can do themselves, then there are those that require professional maintenance. Either way, both should be done routinely.
While maintenance takes time and money, what is important is that it prevents the inconvenience and discomfort of a failing AC. Moreover, it keeps the air conditioner from consuming more energy than it should, taming utility bills. Another advantage of a well-maintained AC is that it will last considerably longer compared to ACs that are ill-maintained.
Survive the Heat with Local Expert HVAC Service
There are many possible reasons why an air conditioner will fail to blow cold air into the house. After ruling out some possible causes like dirty indoor filters, blocked air registers, or thermostats that were set incorrectly, it is best to call for professional servicing.
To get the expert service your family deserves, get in touch with us at Reliable Standard. We repair, maintain, and install all brands and types of residential and commercial air conditioning systems across San Diego and neighboring areas. Call us up through our hotline or schedule an appointment through our easy-to-use online scheduling system.