Refrigerant

How refrigerant moves heat

Refrigerant exploits a basic physical fact: a liquid absorbs large amounts of heat when it evaporates, and a vapor releases that heat when it condenses. In cooling mode, low-pressure liquid refrigerant enters the indoor evaporator coil, boils into vapor by soaking up heat from household air, then travels to the compressor. The compressor squeezes the vapor to high pressure and temperature, and the outdoor condenser coil releases the captured heat to outside air as the refrigerant turns back into liquid. An expansion device drops the pressure again, and the cycle repeats continuously while the system runs.

Refrigerant types have changed over the decades for environmental reasons. R-22 was phased out of production for new equipment, R-410A became the standard for most systems installed since the 2010s, and lower-global-warming-potential refrigerants such as R-454B and R-32 are now used in new equipment.

Refrigerant leaks and older systems in the Philadelphia area

A correctly installed system never consumes refrigerant — if levels are low, there is a leak. Symptoms include warm air from the vents, ice on the refrigerant lines or evaporator coil, hissing sounds, and long run times. Repeatedly topping off a leaking system wastes money and stresses the compressor. For aging systems that still rely on phased-out refrigerant, a major leak often tips the repair-versus-replace decision toward a new unit, since the old refrigerant is increasingly scarce. A licensed technician can pinpoint the leak, weigh the repair against the system's age, and restore the correct factory charge.