SEER considers efficiency throughout cooling season, not just during the hottest summer afternoons. At 95 degrees, we're talking about EER. Higher SEER units also tend to have higher EERs, but this isn't a perfect correlation. This has always been true... so your 9 SEER systems probably run at an EER of about 7 in hot days.
Originally posted by kevin57
REMEMBER, WITH AIR COOLED SYSTEMS, AS THE TEMPERATURE GRADIENT BETWEEN OUTSIDE AIR AND THE FREON RUNNING THROUGH THE CONDENSER SHRINKS, THE SEER RATING DROPS. SEER TEST RATINGS USE A OUTSIDE AMBIENT TEMPERATURE OF 82 DEGREES TO DEVELOP THE ENERGY RATING...WHEN A 14 SEER UNIT IS RUN IN OUTSIDE TEMPS OF 95 DEGREES, THE SEER DROPS TOP 12.17 AND AT 115 DEGREES OUTSIDE TEMP, THE SEER DROPS TO ABOUT 10.25...THAT'S WHY FOLKS IN THE SOUTHWEST USE WATER COOLED CONDENSERS...BASICALLY, THESE WATER COOLED UNITS HAVE AN EER OF 18 AND ROUGHLY A SEER OF 21 OR 22...