Trevor Ariza hit six 3-pointers and scored 24 points to help Houston improve to 4-0. The Rockets made 16 of 34 3-pointers and dominated the Sixers 47-31 on the boards.
Harden made his first 17 free throws and the Rockets had assists on 27 of 32 field goals.
Tony Wroten led the winless Sixers (0-4) with 20 points and K.J. McDaniels had 14.
Ariza picked up in Philadelphia where he left off in March when he scored a career-high 40 points and spoiled Allen Iverson's jersey retirement celebration night. Playing for Washington, Ariza made all six 3-point attempts in the first quarter for 24 points and finished 14 of 23 from the floor overall.
He was nearly as potent for Houston in the first. Without a hand in his face, Ariza buried open shots from the corner and the Sixers made no attempt to stick a defender on him. He made all four 3s, scored 14 points and helped the Rockets race to a 13-point lead. Ariza was 5 of 6 on 3s for 19 points by halftime and helped push the Rockets' lead to 55-54.
The Sixers have put wins on the farthest back burner this season and are focused more on player development — and those high draft picks dangled as bait for all the losing.
Noel is one of the projected cornerstones and he dazzled at times in the first half. Noel had four steals, stripping Howard on one possession, and five assists in the first half. But Noel, the 6-foot-11 rookie center, failed to grab a rebound until there was 2:40 left in the game.
Noel ended the third with a leaping, one-handed stuff of James Harden's two-handed dunk attempt that brought the crowd to its feet.
He picked off a bounce pass near Houston's 3-point line and soared home with a dunk early in the fourth to cut it to 80-76. The fun wouldn't last long. Noel, who made a brief pit stop in the locker room, was on the bench for a chunk of the fourth and trainers worked on his right hand and wrist.
The Sixers haven't been a total loss this season, playing competitive ball for the first three quarters in four games. They've hit a wall in the fourth when opponents pick up their pace of play and take over. This Sixers' team simply is not talented or deep enough to pull off a win against a contender like Houston.
Harden's third 3-pointer built a cushion late in the fourth and Isaiah Canaan followed with his own from the corner for a 93-84 lead. Canaan's next 3 gave the Rockets a 10-point lead and they put away the pesky Sixers for good.
Rockets: Houston played without guard Patrick Beverley (hamstring). ... Howard was a game time decision with a knee injury. ... The Rockets led by as many as 16.
76ers: The Sixers will kick off their "Stars and Stripes" military program with a Tuesday practice for service members at Joint Base McGuire-Dix-Lakehurst. ... Sixers center Henry Sims did not start for the first time this season as he battled an illness. ... The Sixers had one lead all game. ... McDaniels was 3 of 4 on 3s and the Sixers went 11 for 22.
Rockets: Houston plays Tuesday at Miami.
76ers: Philadelphia is home Wednesday against the Orlando Magic.