Both advantages were set up by the speed of center Matthew Lombardi, who twice drew hooking penalties as he attempted to go around the Avalanche defense.
Langkow opened the scoring at 8:19 with a tap-in into an empty net after Jarome Iginla's in-close shot produced a rebound that Jose Theodore stopped but couldn't control.
Conroy made it 2-0 at 14:38, again on a rebound, knocking in a loose puck after Theodore stopped Dion Phaneuf's shot from the blue line.
Calgary's power play, which finished 2-for-4, entered the night ranked 29th in the NHL at home. It was the first time in 30 home games, dating back to Oct. 30, that the Flames scored multiple power-play goals.
The Flames moved two points ahead of Colorado and into a tie for sixth place in the Western Conference with Vancouver, which won 4-1 in Edmonton. The Flames and Canucks moved to within one point of Northwest Division-leading Minnesota, which will play the Canucks on Friday and Calgary on Saturday.
After a disappointing 1-3 road trip, Calgary played as it did before leaving home. The Flames are 5-0-2 in their last seven at home and play three of their next four there before wrapping up the season with four road games.
Ben Guite scored the lone goal for Colorado. After a blistering stretch in which the Avalanche won eight of nine, the team has lost three straight. They hope to have Peter Forsberg (groin) and Paul Stastny (flu) back in the lineup Saturday at Edmonton.
The Flames limited the Avalanche to just 10 shots through the first 40 minutes, but Colorado got on the scoreboard in the third.
With Ryan Smyth parked in front of goalie Miikka Kiprusoff, Guite got to a loose puck and knocked in his 10th goal at 5:52.
Kiprusoff finished with 15 saves to improve to 36-22-10.
Notes: The next assist for Colorado's Joe Sakic will be No. 1,000 in the NHL. ... Calgary's power play had scored two or more goals in four of its first eight home games. ... Calgary's lineup changes included the return of C Mark Smith, who was scratched the previous seven games.