They go alot higher than 14 seer, up to 19? and so do costs but
efficiency increase is not linear, it declines with each seer up. Tranes
site has a seer sheet showing seer increase and $ saved. You have to
run your numbers and get other bidders to help you better. A load
calculation in writing is also a good idea incase you are oversized,
higher seer units ive heard don`t pull out as much humidity so sizing is
important. 13 seer might soon the new minimum you can buy.