Hardin also had 11 assists and Howard hit 9-of-14 shots while snagging 13 rebounds in his return to Staples Center after a disappointing 2012-2013 season with the Lakers.
Howard caught plenty of flak from the crowd, but the Rockets took the sting out of the booing by dominating the depleted Lakers from start to finish.
Houston led 32-22 after one quarter, shot 50 percent from the field and out-rebounded Los Angeles 56-32. The Rockets won their eighth consecutive game.
Wesley Johnson scored 24 to lead the Lakers, who lost a franchise-record eighth consecutive home game. Kendall Marshall had a double-double of 20 points and 16 assists.