It was very cold weather, and our outside unit froze over. We called Airflow Service Company and they quickly arrived to diagnose and fix the problem. We have used them for about two and one half years now, and we are delighted with them! That is why we keep using them. Their employees are always very friendly, and punctual, and also very direct about the problem. They tell you what is wrong and try to help you solve the problem without running up more costs than you have to. I also like the fact that Airflow Service Company is so available to us. We often get service the same day we call.