Manager Nathan Jones handed competitive debuts to three of his seven summer signings in Ethan Horvath, Luke Freeman and number nine Carlton Morris - the latter who was paired with Elijah Adebayo up-front.
Captain Sonny Bradley led a back five consisting of James Bree, Gabe Osho, Dan Potts and Amari'i Bell, while Allan Campbell and Jordan Clark joined summer signing Freeman in midfield.
Reece Burke, Alfie Doughty and Luke Berry missed out through injury after playing in last Saturday's final pre-season friendly with West Ham.
The Hatters started well with a raucous home crowd behind them, and with Freeman revelling in his role just behind the front two.
The summer signing had the first attempt on goal, forcing John Ruddy to dive full length to push his right-footed shot away after Freeman had danced through the Blues' defence in the ninth minute.
That opening was created by Campbell and Clark's tenacity in midfield, and the trio were smothering Birmingham's engine room, with Adebayo and Morris also pressing high up the pitch.
Several dangerous looking crosses were whipped in by Bree and Potts, with Adebayo and Morris the intended targets, while a smart short corner routine between Bree and Clark presented Freeman with a shooting opportunity, but he miscued into a thicket of legs.
Juninho Bacuna had Birmingham's first shot on 25 minutes, dragged well wide after seemingly using his hand to emerge with the ball from a challenge with Bradley, then Maxime Colin saw an effort beaten away by Horvath four minutes later.
Town were playing well and Bree was next to have a go, his 25-yard drive flying wide of Ruddy's right post, before Adebayo set Morris racing clear, but the Blues' defence managed to get back to block his shot after the former Barnsley man checked back onto his left foot.
Przemyslaw Pacheta tested Horvath with a volley from just outside the area two minutes before half-time, but the American internations dealt with it comfortably and the sides headed in for the break level.
Pacheta shot straight at Horvath within a minute of the restart, but the Hatters were soon back on the front foot with Freeman sending a left-footed curler just wide of the post on 48 minutes.
Marc Roberts saw a header blocked from a corner, then Bacuna fired into the side-netting in an open first five minutes of the second half.
But it was Morris who would go as close as anyone in the 53rd minute when he made inroads down the Hatters' right after being released by Campbell, chopping back onto his left foot only to see his attempted curler whistle inches wide of the far post.
Three minutes later the summer signing was at it again, swivelling on the edge of the box to create space for a right-footed shot that had Ruddy stretching again after more good work in the build-up from Clark.
A wonderful team move that started in the Town's own half with a short free-kick led to Clark and Bree creating the next opening for Campell in the 65th minute, but the recently capped Scotland international's side-footed effort was blocked.
Potts did well to jump with Roberts and divert the Birmingham defender's header wide of the far post two minutes later, before Jones introduced his first game changers with just over 20 minutes to go.
Cauley Woodrow made his competitive return to Kenilworth Road, with the fans quickly reminding him he's "one of our own", in place of the excellent Freeman, while Harry Cornick came on in place of Morris, who had come as close to breaking the deadlock as anyone.
Cornick and Adebayo quickly combined to set Bree free down the right, but Campbell could't quite get on the end of his low near post cross with Ruddy gathering at the second attempt.
The former Everton keeper then had to be equal to a fierce strike by Woodrow from the edge of the box as the Hatters sought a breakthrough, before Cornick bent one just the wrong side of the post with eight minutes to go, again benefitting from Campbell's energetic pressing.
Jones made his third change in the 84th minute, bringing on Cameron Jerome for Adebayo, and the veteran striker was straight into the thick of the action sending in an inviting cross from the left, but Birmingham defended it well and it was Roberts who sent the next goalward effort just off target, heading over at the other end when well placed.
ATT: 9,921 (1,032 away)