HVAC engineers design, install, maintain, or repair heating, cooling, ventilation, and refrigeration systems. In order to become an HVAC engineer, you will usually need to complete a four-year bachelor's degree in an engineering-related field and may need to pass certain certification exams, depending on where you live. HVAC engineering and manufacturing is a growing field, with opportunities for various levels of professionals.

A heating, ventilation, and air conditioning (HVAC) controls technician installs, calibrates, and repairs HVAC equipment to ensure that a building has the proper environmental conditions. The HVAC controls technician also interfaces with various clients and works with other skilled trades in the construction of new homes, offices, and industrial facilities. Typically, a HVAC controls technician works in environments that contain dust, fumes, temperature extremes, and high levels of noise. Most employers hire individuals that have graduated from an accredited HVAC program and have at least two years of experience working as an HVAC control technician.

The primary duty of an HVAC controls technician is to install, repair, and maintain control systems. After receiving a work order, the HVAC controls technician visits the site to examines the equipment. A series of diagnostic tests are performed to determine the problem and identify a proper solution. This involves reading control logic diagrams and wiring schematics to properly adjust pneumatic control systems. The temperature, humidity and pressure are all calibrated and tested.

Heating, ventilation, and air conditioning (HVAC) systems are essential to providing comfortable living and working environments. Some HVAC units are small and relatively simple in design, such as those found in houses and apartments. Others are huge, complex machines that heat and cool large factories, buildings, schools, and hospitals. Regular HVAC maintenance is essential to ensure that units do not break down and that they operate at maximum efficiency. People can usually perform simple HVAC maintenance tasks themselves on small units by following owner's manual guidelines, while large systems require the expertise of trained mechanics.

Residents of apartments and houses should inspect their HVAC units every few months to keep them working properly. Owner's manuals usually include simple preventive maintenance checklists with helpful instructions and diagrams. They explain the tools and techniques needed to take off covers and identify the internal parts.