Hi! My air conditioner has had its gas checked and filters cleaned, they say it's working fine but doesn't get temp below 25. Before it could easily get 18. What could be wrong? Thanks . Robin

Anyone who checks the "gas" is probably a rip-off artist. Refrigerant does not need to be topped off every now and then. If it is low you have a major problem requiring you to find the leak, weld it closed, and vacuum out the system after replacing the filter dryer, then recharging. You more than likely have a dirty system where you need to pull out the blower and clean it and then spray down the inside coils with coil cleaner and pressure wash them with a 1500 psi electric pressure washer or a good hose nozzle. This should be done at least once a year, unless you have a HEPA filter and then you may go a little longer. Most company AC repairmen hate to clean a unit because it is a nasty job and takes a lot of work, but it is needed and your AC will not work dirty. It will run up your electric bill and finally quit working and freeze up, acting somewhat like it is low on refrigerant. Scam artist will add gas to it to raise the pressure but that makes it burn up more quickly so you need to buy a new one.