Home Page for Carrier air conditioning, heating Carrier is a world leader in heating, air-conditioning and refrigeration solutions. Built on Willis Carrier’s invention of modern air conditioning in 1902, Carrier is a world leader in heating, air-conditioning and refrigeration solutions. We constantly build upon our history of proven innovation with new products and services that improveResidential Systems · Product Registration · Commercial · Contact Us · Products and Services · Careers Thermostat Wiring Colors Code | HVAC Control Wire Details Jul 04, 2008Thermostat Wiring Colors Code - High Performance HVAC Thermostat Terminal Designations. Turn the power off before proceeding! Always follow safety instructions especially with electricity. This should be done at the circuit breaker for both the condenser and the air handler/furnace.