ENERGY STAR certified heat pumps have higher ratings for seasonal energy efficiency ratio (SEER), energy efficiency ratio (EER), and heating seasonal performance factor (HSPF) and use about 5% percent less energy than conventional new models.
1 8 bits that contain the Type of Service, also referred to as Quality of Service (QoS), which describes what priority the packet should have, 2  16 bits that contain the length of the packet in bytes, 3  16 bits that contain an identification tag to help reconstruct the packet from several fragments, 4  3 bits.
The second hexadecimal character of the 64 bit Interface ID must be 0, 4, 8 or C i.e. X8XX:XXXX:XXXX:XXXX where the 8 can be replaced with 0, 4 or C (71st and 72nd bit set to 0) ++ See text from RFC4291 below. The use of u/g bits came after discussions about the 8+8/GSE proposals.