Lowrie provided a pair of two-run singles and Brandon Moss drove in three runs on two hits for the A's, who jumped out to a quick 6-0 lead and went on to claim the opener of a three-game home series.
Tommy Milone (3-0) logged a third straight win to start the season, yielding a pair of runs on eight hits. He didn't issue a walk and struck out six as Oakland improved to 10-4 on the season.
Astros starter Erik Bedard (0-1) managed to record only one out before exiting, allowing six runs on a pair of hits and four walks.
Jose Altuve and Carlos Pena each supplied an RBI for Houston, which dropped a third straight.