When hiring an independent heating and air conditioning specialist never be afraid to ask to see their heating and air conditioning certification. A lot of independent heating and air conditioning specialists can operate without actually have gotten their heating and air conditioning certification. While a lot of them are so good you would never know, some of them it actually shows and they really do not know what they are doing. This could be bad for your central heating and air conditioning system unit. Because if they were to break your central heating and air conditioning system unit while working on a heat and a/c tune up and check up or if they were to break it when trying to repair it, you would have no liability insurance on their end and you would be responsible for it. In other words, you would be stuck having to invest into a brand new, up to date, possibly very expensive and really unneeded central heating and air conditioning system unit! This is something you most definitely do not want to happen. So this can be all avoided when hiring an independent heating and cooling specialist by simply asking them for their certification. If they are on the level, they will not get mad and have no issue showing it to you. If they give you an attitude or get angry, move on right away and find someone else! That is the sign that they are operating without a heating and air conditioning certification.