If it's just occurred to you that your air conditioner has been running nonstop, you should investigate to see if there is a problem. If it's hotter than usual outside, it could just be due to the AC struggling to keep your home comfortable. However, if it is an average day when your AC would normally shut on and off, your air conditioner might be in need of repairs. Here are some things that can cause your air conditioner to run continuously.
The coils in the indoor evaporator and the outdoor condenser need to be clean so the air conditioner works properly. If the coils are dusty or dirty, your AC might need to run continuously to maintain a cool temperature. The outdoor coils are particularly prone to collecting dirt, leaf bits, and other debris. An HVAC contractor can clean the coils as part of a tune-up that inspects for problems and gets your AC working right again.
Be sure to check the filter because a dirty filter is often the cause of many air conditioner problems. Clean it or replace it to see if it makes a difference. Also, consider if you recently replaced the filter with a new brand. It's possible the new filter isn't letting enough air flow through. If cleaning doesn't work, try putting in your usual brand to see if that makes a difference.
Check the thermostat settings to make sure the temperature is set high enough for your AC to shut off. If it got bumped and it's too low, your AC may not be able to reach the target temperature even when it runs all day. Move the temperature to a higher range than the temperature in your house. If the AC doesn't shut off soon, the thermostat might be broken. You'll need to call an HVAC contractor to replace it.
Low refrigerant is an issue for your contractor to resolve. If the refrigerant has leaked out, the air blowing through your AC won't chill. You'll notice the air isn't cool when it blows out of the register. Your air conditioner has to run continuously to try to reach the target set on the thermostat. Refrigerant shouldn't leak out under normal conditions, so the contractor will need to make repairs before refilling it.
If your air conditioner is running continuously and your house is stuffy and warm, it's very frustrating. However, even if your AC is cooling your house down, but is still running all the time, you want to call for repairs. If you don't, you may get an unwelcome surprise when you open your next electric bill.
Visit a website like http://www.coeheatcool.com to learn more.