In a first half of few chances, the deadlock was broken on 17 minutes when Billy Bodin beat Steve Tully with a nutmeg and was then tripped inside the box by the Exeter full-back.
Howe stuttered his run and waited for goalkeeper Artur Krysiak to go to ground before rolling the ball down the middle.
Exeter got better as the half wore on, but with no out-and-out striker on the pitch, they lacked a genuine goal threat. Jimmy Keohane had their best chance, but he fired wide of goal after good work by debutant Mark Molesley.
In truth, Torquay goalkeeper Michael Poke barely got his gloves dirty as his team defended well.
Exeter had nearly all of the play in the second half, but the closest they came was when substitute Jamie Cureton saw his effort well saved by Poke.
Guillem Bauza also had a great chance at the death for Exeter, but he headed wastefully wide as the Gulls held on for the win.