honest and on time. In the end the problem with my ac had three possible causes. He ruled out one by looking in attic. The other two we had to wait for line to defrost. And if the line froze over again that means low Freon. But if AC works fine after that that means it was just a dirty furnace filter. And that's the one it was for me. So keep your filter clean. If your line freezes over turn off unit until defrosts 4 hr to be shore. And try again with clean filter.