"HVAC systems of any home are expensive units and no homeowners would like to spend on its repairs numerous times after investing a considerable amount on its purchase. To avoid the unnecessary expenses on HVAC units, it is important to take good care of them. It can be done by scheduling a routine maintenance of your HVAC units by reputed HVAC contractors. Whenever an HVAC contractor comes to your place, these are the things you can expect from him. They will thoroughly check the system functions along with the safety controls to ensure that the system operates without any difficulty. In this step at the very beginning the outdoor unit that is the condenser is checked and then the indoor unit that is the evaporator coil is checked. The HVAC contractor has to check both the mechanical and the electrical components of the two units and if any part needs repair they should do it accordingly.As part of the systems check, the air filters are replaced and if there is any kind of biological growth like mold it is removed.Lubricating all the moving parts of an air conditioner is also a necessary step of the routine checkup. This is done in order to avoid excessive friction. It is also the duty of an HVAC contractor to check the levels of refrigerant in an HVAC unit because low levels of refrigerant have adverse effect on the compressor.Last but not the least; the ducts should be inspected for dirt and leaks. If leaks are found it should be sealed immediately."