This article presents a validation and qualification on heating, ventilation, and air conditioning(HVAC) systems. An HVAC system is required for suitable temperature maintenance, continuous air flow, and also keeping the air fresh, which ultimately helps in the prevention of cross-contamination and air accumulation and also ensures the availability of cool air on the premises. The quality of air ventilation in the pharmaceutical business has a considerable impact on worker safety, material efficacy, including raw materials, in-process items, and final products, and machinery. It ensures the optimal quality of air, as directed by the regulatory guidelines. Three degrees of validation are important for HVAC systems: installation qualification (IQ), performance qualification (PQ), and operational qualification (OQ). Air variations per hour, air circulation velocity, and air circulation pattern, pressure differential, recovery test for temperature and humidity, temperature and humidity uniformity, filter leak test, particle count, loss of utility test, compliance test, filter integrity test, and fresh air determination are some of the parameters to be assessed for the HVAC system validation.The validation tests that are mentioned in this article have acceptance criteria and procedures for conducting the tests that are provided by the current good manufacturing practices (cGMP) guidelines.