Maximize your comfort with their top-of-the-line components The XL20i and XL16i heat pumps feature ComfortLink II technology, providing the ultimate comfort connection for efficiency, convenience and enhanced reliability. Lets you and us interact with your system like never before.  It provides real-time operating information and flexible remote telephone access.   The XL15i is the quietest single-stage system in the Xli family and offers high-end performance at moderate prices.  The XL14i features low-resistance airflow providing reliable comfort throughout your home.