Espindola got the scoring play started when get rolled off Houston defender Jermaine Taylor on the turn and squared the ball to Rolfe, who hammered his strike into the bottom right corner past the outstretched arm of Houston goalkeeper Tally Hall.
Houston's best opportunity of the first half came in the 43rd minute when the ball fell to Giles Barnes on the edge of the penalty area and he unleashed a wicked strike on goal that forced United goalkeeper Bill Hamid to make a diving stop.
The hosts doubled their lead in the 63rd minute when Espindola collected a pass form Rolfe on the left wing. He beat Houston defender David Horst and drove a low strike into the bottom right corner of the net for his fifth goal of the season.
Things unraveled from there for Houston as it failed to generate many scoring chances following Espindola's goal and went down to 10 men in stoppage time when Brian Ownby was shown a straight red card.
The result lifts United into second place in the Eastern Conference with 18 points, while Houston remains on 17 points.