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Sierra AC did my AC replacement recently. The installers have done a nice and clean jobs. However, when I contacted their office for follow up ceiling entry repairs, I go no answers. I called their customer service three times, every time they promised they would call me back for scheduling. In fact, there was no one calling back. Without ceiling repairs, my AC installation can only be considered half done. Therefore I give Sierra AC 3-stars here. Ceiling holes allow dust and bugs to enter my bedroom easily. If Sierra AC can get holes fixed quickly, I would consider raising their star ranking. If this repairs got seriously delayed, I may have to consider lowering their star rating. Hope they take care post-insulation repairs seriously. Otherwise the project is still not done. Progress- three days after my comments above, Sierra AC called me back and scheduled the ceiling repairs. Now the ceiling looks fine. So I raised their star level to 4 . Nice job done. The only thing that prevented me from giving a five star is the AC system has not be tested for cooling, since it was installed in winter. I will need to reevaluate the AC function in summer.