Residential Air Conditioning (A/C) provides comfort to millions of homes worldwide. According to the Air Conditioning and Refrigeration Institute, there are over 60 million air conditioners using fluorocarbons in the US alone. People lead more productive and

Residences use air conditioning systems with an external fan and an internal refrigeration unit.

healthy lives due to controlled temperatures and humidity in homes. During periods of unusually hot weather, air conditioning has been credited with saving lives. Three system types are available in the global residential market: window room air conditioners, ductless split air conditioning systems and ducted central air conditioning systems.

The vast majority of residential air conditioners use hydrochlorofluorocarbon 22 (HCFC-22). This refrigerant will be available for many years, although the Montreal Protocol dictates its eventual phaseout. The primary HCFC-22 replacement in the US residential a/c market is hydrofluorocarbon 410A (HFC-410A). Hydrocarbons, such as propane, are also possible choices but their inherent flammability and associated risk mitigation cost are issues for use in residences. HFCs and the continuing availability of HCFC-22 will allow manufacturers to provide the most energy efficient equipment. This reduces energy consumption and the resulting emissions of CO2 (carbon dioxide).

Life-Cycle Climate Performance is expressed as kilograms of CO2. This includes both the greenhouse gas emissions ("direct effect") and the energy consumed ("indirect effect"). Air conditioning system operation is energy intensive and, consequently, dominates the LCCP. However, it is also important to minimize system leakage and refrigerant loss during installation, commissioning, servicing, decommissioning at the end of life, and ultimate equipment disposal. Other considerations include the system cost and the safety of users, service technicians and the public.

The direct warming effect due to refrigerant emissions for residential air conditioning systems with fluorocarbon refrigerants is less than 5% of total LCCP. System efficiency is much more critical to LCCP than the direct refrigerant emissions. The direct effect of a hydrocarbon such as propane is very small but its use requires significant fire risk reduction investment. A study by a US equipment manufacturer indicated that hydrocarbon use would increase residential ducted system cost by over 30% (Treadwell, 1994). This additional cost was necessary to reduce the risk of fire. This can be accomplished by, inter alia, isolating all brazed joints from the indoor air, placing all electrical components in a separate sealed control box and utilizing a secondary loop to isolate all flammable refrigerant containing components from the indoor air. Use of a secondary loop will decrease efficiency, increasing energy consumption. The additional system cost is better spent increasing the inherently safer fluorocarbon system efficiency, further reducing environmental impact.

A 1997 report (Keller, 1997) showed that fluorocarbon systems provide the lowest LCCP per unit of investment. A 10 SEER propane system would cost 30% more than the conventional HCFC-22 system and have an

Residences use air conditioning in warm and humid global locations.

LCCP of 33,000 Kg CO2. If the additional system costs required for propane were instead used to purchase a 12 SEER unit with HCFCs or HFCs, the LCCP would be reduced to between 29,300 and 29,850 Kg CO2 (Dieckmann, 1999).

HFCs offer the best solution for meeting long-term residential air conditioning requirements. Commercially available throughout the world, HFCs are energy efficient, low in toxicity, cost-effective, can be used safely and are reusable. Use in efficient systems reduces fossil fuel consumption and the corresponding CO2 emissions.

The industry actively advocates the following principles for all refrigerants worldwide:

• Contain refrigerants in tight systems and containers, minimizing atmospheric releases;
• Recover, recycle and reclaim refrigerants;
• Train all personnel in proper refrigerant handling;
• Comply with applicable standards (e.g. ISO 5149, ASHRAE 15), governing proper installation and maintenance of machinery spaces;
• Size equipment to match the specific need, thereby minimizing the refrigerant amount; and
• Design, install and operate to optimize energy efficiency.

The Alliance for Responsible Atmospheric Policy is a leading industry voice which coordinates industry participation in the development of reasonable international and U.S. government policies regarding ozone protection and global climate change.

The Alliance for Responsible Atmospheric Policy 2111 Wilson Blvd., Suite 850 - Arlington, VA 22201 Phone: (703) 243-0344 - Fax: (703) 243-2874 E-mail: info@arap.org