The XL19i ultra-efficiency air conditioner has a SEER rating of up to 19.5. The unit features two compressors—one to operate in milder weather, the other to run on extremely hot days. A variable-speed fan motor adjusts its speed to save energy and provide maximum comfort while operating quietly. Compressor sound insulators also reduce operating noise. Woven spine fin cooling coils provide less resistance to airflow, increasing the efficiency of heat transfer. 608.787.2000. www.trane.com. Circle 161.