My son has always been a great napper and consistently took two 1.5 hr naps a day. We transitioned him to one nap shortly after 15 months because he stopped taking the afternoon nap and would be irritable by the end of the day. He had a hard time with the transition because he'd be overly tired in the morning. So we started nap time at 10:30am, and within several weeks, started pushing it back to 12:30pm. At first, he'd only nap for an hour, but as we pushed the nap time back, he'd get comfortable with his new nap time and sleep a little more. It also helped to get him out of the house and release some energy so he'd be ready for a nap. He then started napping for 3 hrs straight - lucky me. Be consistent, keep him active during his waking hours, and hopefully he'll tire out and sleep better to give you a break!