Jason Castro and Carlos Pena added two runs apiece for the Astros, who won two of three games against the Mariners to take their first series of the season.
Brad Peacock (1-1) held Seattle to three runs on four hits and a walkover in the win.
Blake Beavan (0-1) allowed five runs on nine hits in the loss, Seattle's fourth in their last five games.
Costly malfunction causes beer flood at Boston-area brewery
Megyn Kelly: Santa Claus and Jesus are both white men