How long does it take to fix an air conditioner? That depends on the problem and how complicated it is. If it's something simple, like a filter that needs changing or a refrigerant that needs recharging, you're probably looking at a matter of hours to get it done and get your nice, cool air flowing again. But if the problem is more complex—say, a vital component that needs replacing or a tricky electrical fault that needs diagnosing—then you might be looking at several days, possibly even longer. When you first call the repair service, be clear, and as you can, about what your unit is doing (or more accurately, not doing), and ask the tech for an estimate once they've had a chance to assess the situation.