Is your air conditioner running but not blowing cold air? What's the point then, right? Your system may be experiencing some issues that are causing the air to blow out not as strong or not as cold as usual. Here are some common reasons why this may be happening and how to resolve these issues.
With all the moving parts that make up an air conditioning system, you're bound to experience some problems from time to time. To see a basic understanding of how a central AC system works, click here.
One of the most common issues we come across is an air conditioning unit blowing warm air. Your AC may turn on, but it might not be cooling down your home properly. This can be due to a variety of factors, which we'll explain below.
6 Reasons Your AC Isn't Blowing Cold Air
Thermostat is set incorrectly
The cooling process won't start unless the thermostat says to - so if your thermostat is set incorrectly then you won't feel that cold air. Make sure that it's set to cool and that the fan is set to auto or on. After the system kicks on, you can wait a few minutes then check for cold air blowing from the vents.
Dirty air filter
A dirty air filter isn't a complex issue, but it can cause many problems with your HVAC system. If your air filter is dirty you may find ice on your air conditioner, water leaking from your unit, or your unit running inefficiently and costing you more in energy bills. You may also notice that your AC is blowing warm air when it should be cool. The filter's job is to catch dust, dirt, pollen, and other contaminants to keep them from being distributed through your home. However when you don't clean or change out the filter, it will obstruct the airflow and cause your home to overheat.
To prevent this issue, be sure to keep up with annual AC maintenance in addition to changing out your filters at least every three months. 
Clogged condenser coil
If you air conditioner is on and running but not blowing cold air inside your home, check for buildup on the outdoor condenser unit. When operating correctly, the condenser fan draws air into the outdoor unit to pull heat energy out of your home. If dirt, grass, and other debris build up between the metal fins (which line the exterior the unit), then the condenser coil can become clogged as well. A dirty coil can lead to reduced efficiency and lack of cool airflow.
To prevent and fix this issue, be sure to clear away debris, clean the unit with a brush attachment, or rinse the unit off with a hose. You should also be sure not to landscape too close to the unit as it needs room to pull in and release air.
Frozen evaporator coil
When it comes to the indoor unit of your air conditioning system, the evaporator coil is essential to providing cool air in your home. If you notice frost forming on the tubing, excessive condensate drainage, higher utility bills, or warm air coming through the vents, you may have a frozen evaporator coil.
To resolve this issue, it's best to have an HVAC technician come out and handle it.
Refrigerant leak
The refrigerant in your AC system works to absorb heat from the indoor air to be released outside. A refrigerant leak may cause your unit to not blow cold air and run for longer periods of time without adequately cooling your home.
To fix a leak, your HVAC professional will have to recharge the system or seal the leak if it's big.
Undersized air conditioner
Air conditioners are "sized" in terms of BTU's, which measure the amount of cooling they can provide. As temperatures outside rise and you need to use your AC more, you may notice that you need to run it for longer periods of time to try to keep your house cool. An undersized air conditioner will turn off and on more often to try to keep up, which results in higher energy bills too.
When sizing your unit, your contractor should take several factors into consideration including the size of your home, the number of windows and doors, the climate, and more. To solve this issue, you may need to replace your system. You can also opt for adding single-zone ductless units where there is inadequate cooling.
Most of these issues with your central air conditioner have simple fixes. If your outdoor unit is a heat pump, these reasons still apply. If you're unsure what's causing the lack of cool air to begin with, call your HVAC contractor to come assess the issue. Resolving a problem sooner rather than later will extend the life of your HVAC system and ensure that you're comfortable in your home.
If you live in the Delaware Valley/Greater Philadelphia area and would like to find comfort within your home, visit our website or give us a call at 215 - 245 - 3200 to learn more.
