There are many things that can go wrong with your home's central air conditioner that cause it to stop working properly. One of those issues is a lack of refrigerant, which is likely due to a leak somewhere in the system. Here are some ways to tell if you have low refrigerant and if you need to investigate the problem further with AC repair services.
The most obvious symptom of a refrigerant leak is going to be warm air. If there is not enough refrigerant to absorb the heat and carry it out of your home, the AC is only going to produce warm air when the system is turned on. The process will be quite gradual, with the temperature of the air slowly rising over time as more refrigerant is lost from the system somewhere. It may be worth using a thermometer to monitor the temperature of the air coming out of the vents so that you know what temperature to expect.
Frozen Evaporator Coil
Have you ever looked inside your air conditioner's air handler and noticed that the coils are frozen? It may seem a bit counterintuitive, but frozen coils are actually a big problem that can contribute to warm air, with a common cause being a lack of refrigerant.
Frozen coils happen because your air conditioner is overworking due to not having enough refrigerant, and condensation is getting trapped in the air handler. That condensation then freezes on the coils and causes ice to form. The ice is not enough to actually chill the air being pushed through your vents, and you also get warm air as a result.
If you take a look at the actual refrigerant lines traveling in and out of your home, you may notice a hissing sound coming from them. This could be due to a small leak in the lines and you are actually hearing the refrigerant escaping. A good way to tell if it is actually a leak coming from the refrigerant line is to cover it with soapy water, since the leak will cause bubbles to form on the line.
Low Refrigerant Reading
Of course, you can always have the air conditioner checked by a professional to see what the actual refrigerant levels are. They'll connect a diagnostic manifold gauge to the air conditioner and instantly be able to tell if the unit doesn't have enough refrigerant. They can then start troubleshooting the problem and fix the leak.