Automotive air conditioning development

The first factory‑installed automotive air‑conditioning system was introduced by Packard in 1940, using DuPont’s R‑12 (Freon‑12) refrigerant. Early units were expensive and occupied space behind the rear seat, limiting adoption, but the technology spread through the 1950s and by 1970 roughly half of new U.S. cars were equipped with air‑conditioning.

The refrigerants used have changed over time. R‑12 was phased out because it damaged the ozone layer and was replaced in the 1990s by R‑134a, a hydrofluorocarbon that avoided ozone depletion but proved to be a persistent greenhouse gas. The EU banned R‑134a in new cars in 2017, and the current standard R‑1234yf reduces global‑warming impact, though a 2026 study found it degrades into trifluoroacetic acid, another persistent compound with health concerns.

Modern safety guidance reflects both climate‑driven demand for interior cooling and health considerations. Drivers are advised to ventilate hot vehicles before starting the engine, use the air‑conditioner on low temperature with the fan at full, limit recirculation to short periods, and keep interior temperatures only a few degrees cooler than outside to avoid circulatory problems. These practices aim to maintain driver alertness while mitigating the environmental and health impacts of automotive refrigerants.