Not every Heating & A/C serviceman is a real professional, but periodically the Heating & A/C guys are simply guys with tools who taught themselves. How do you weed out the local handymen from the actual professionals? A good quality Heating & A/C contractor is certified & licensed, then the heating or cooling tech should take some classes to prepare, but also better Heating & A/C servicemans go into the field to act as an apprentice for a qualified professional. Then and only then can the Heating & A/C serviceman get the certification tests, and hours in the field they will acquire NATE certification. So, NATE stands for North American Technician Excellence and it is for Heating & A/C repairmen that want to be a chop above the rest. Through NATE the Heating and A/C guy does more than a few tests. The program sets them up with the training that has them prepared to do Heating & A/C repairs, repair & upgrade. You want Heating & A/C contractors that hold this certification specifically. This says that your serviceman was willing to learn the content and take the time for testing his comprehension. Also NATE certification says that the Heating & A/C worker likes you and your choice of home. He wants to do a good job, so he has done the extra steps! Some Heating and A/C businesses make their Heating & A/C servicemans get this certification, though, not everyone does this. So when you are hiring out Heating & A/C work, look to see if you are getting somebody who is legitimately qualified to do this intense work in your home. It is very possible you are just getting a normal handyman who does not have the comprehension or the training. They could potentially ruin your brand current Heating & A/C unit. Take the time to look into your Heating & A/C worker before they come into your home.