If you pull out your home’s air filter, hold it up to a light. If you can’t see light coming through it, it’s most likely been a while since your last heating service, and likely time to get a new one. If it’s a simple disposable air filter, just replace it with a like-size new one. It’s also a good idea to write down the date you installed the new filter, so you know how old it is next time it needs to be replaced. Check the filter packaging to see how long the new air filter is supposed to be used.
If your furnace’s motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. Replacing it is an easy fix. First, turn off all power to the unit and turn off the gas at the gas valve that serves the furnace. Remove the door on the front of the furnace cabinet to give you access to the blower (it might be on a slide-out drawer.) Check the number stamped on the belt and get an exact replacement from a home center or heating supply outlet.
Yes. You should expect to pay a diagnostic fee to cover the cost of the technician's visit, the diagnosis of your air conditioner's problem, and a quote for the repair options. You will be advised of the issue along with recommended options to correct it, which may include a system replacement if your unit is old or significantly damaged. If you decide to replace the system, the diagnostic fee will be credited toward your replacement purchase.