HVAC stands for heating, ventilation, and air conditioning. It refers to the systems that regulate and move heated and cooled air throughout residential and commercial buildings, from homes to offices to indoor stadiums. Although there are many options when it comes to HVAC systems, they all work similarly: taking in fresh air and using a mechanical ventilation system to heat or cool it to a desired temperature. HVAC units also can control humidity levels and improve air quality through air cleaners that capture bacteria, spores, and virus-sized particles. The HVAC technician who comes to your home for a pre-installation evaluation will help you determine which system and options are best for you and your home.