Both companies offer a line of heat pumps with varying specifications. Carrier's top model offers more efficiency, but is slightly louder than Carrier's similar pump. Both of their top models meet Energy Star requirements, but not all of their heat pumps meet the standard.
Trane's most efficient heat pump as of 2015, XV20i Variable Speed, has a Seasonal Energy Efficiency Ratio, or SEER, of up to 20 and a Heating Seasonal Performance Factors, or HSPF, of up to 10. Carrier's Infinity 20 heat pump offers more efficiency, with a SEER of 20.5 and a HSPF of 13.
Both of these top-rated products use variable-capacity heat pumps, a type of pump first introduced by Carrier. This allows the pumps to run on low capacity when possible and reduce energy consumption. The Trane model has a compressor blanket and additional sound-reducing materials, making it the quieter of the two. The sound level of the Infinity 20 is as low as 58 decibels, louder than Trane's sound level of 54 decibels.
Trane offers 11 heat pump options, as of 2015. Carrier offers a greater selection that includes the Infinity, Performance and Comfort series of heat pumps, with a total of 15 heat pumps to choose from.