30 May 2005


This is an overview of information, developed from many sources, in the search for a good
replacement for the dominant refrigerant used in residential and light commercial air conditioners,
HCFC22. The Montreal Protocol proscribes a phase-out timetable for HCFC22. 2010 is the phase-out
deadline for HCFC22 in newly manufactured equipment. A variety of potential alternatives have been
evaluated. An important consideration in the evaluation of alternates is the potential climate impact of
their use. The Life Cycle Climate Performance (LCCP) is a measure of potential climate impact that
takes into account the direct release of refrigerant plus the indirect energy impact of the refrigerant’s use
upon greenhouse gas emissions. The LCCP’s of the following candidate HCFC22 replacements are
compared: HFC407C, HFC410A, propane and carbon dioxide. It is evident that, with respect to
greenhouse gas emissions, the indirect energy impact is many times larger than the direct release effect.
The efficiency potential of these different refrigerants turns out to be doubly important. Other important
characteristics, such as flammability, toxicity and cost, are also reviewed. Residential and light
commercial air conditioning and heat pump products using HFC410A are becoming widely available and
some are setting benchmark efficiency levels.