Trane XR17. $8,400-11,600. 17.25 SEER/9.6 HSPF. Trane XL18i. $9,200-12,800. 18 SEER/9.5 HSPF. INSTALLED COST* Installed cost reflects the average national cost for installing a particular unit or system. Your actual costs may differ depending on where you live, how your home was built and the type of system you select.