The higher the Seer Rating, the more efficiently your air conditioning will operate. The 16 SEER system is the most popular of the two because it provides better efficiency without the high price of two stage 17+ SEER units. You may also qualify to receive a rebate for installing a 16 SEER air conditioning unit. 14 SEER units are commonly installed in rental properties and other buildings because of the lower price, and less concern for operating costs. The 16 SEER typically costs around 14% less to operate compared to the 14 SEER system, a savings which adds up over time.