Brooks Macek had a goal and an assist for the Hitmen (8-2-2), who had a 5-1 lead heading into the third period, and Greg Chase chipped in with two assists.
Josh Thrower added a single goal to round out Calgary's offence.
Dalton Sward and Trevor Cheek each had a goal and an assist for the Giants (2-8-0), who have now dropped four games in a row, and Thomas Foster and Blake Orban had a goal apiece.
Mack Shields stopped 30 shots for the win as Tyler Fuhr allowed five goals on 24 shots in a losing effort.
Calgary went 2-for-5 on the power play while Vancouver went 1-for-5.