Recommend HVAC

Hi. I am wondering if anyone can make a recommendation for a good HVAC person. I currently have through-wall a/cs that are very loud and do not have a good design and air is trapped. I have a new renovation and the a/cs are built-in under the windows with a grill on the front. We chose the largest size opening for the grill, but still the air is not circulating well. I am thinking of moving to a split wall mounted system. I understand they are much quieter. I don't want to call in someone from the manufacturer as they will only sell their product. I want someone to make an unbiased assessment. Thanks.