But their second away win of the campaign was achieved at the cost of a nasty looking ankle injury to England's Ben Foden in the second half.
His replacement, Tom May, wrapped things up with a drop goal four minutes from time.
The only try of the game came after just 70 seconds through Nick Abendanon but Bath were again reliant on the goal-kicking of Olly Barkley, who landed three penalties.
Danger man Kyle Eastmond received only one pass on the right wing.
Scottish international flanker Simon Taylor, one of the most effective performers against Wasps six days earlier, arrived at the Rec straight from the hospital where his wife gave birth to their second child only hours before kick-off.
There were only two changes in the home line-up, Paul James coming in at loosehead prop and youngster Ben Williams replacing the injured Matt Banahan at inside centre.
Myler was preferred to Ryan Lamb at fly-half for Northampton but they were without centre George Pisi and tighthead Brian Mujati with leg injuries and also No 8 GJ van Velze who was serving a four-week ban.
Luther Burrell came into the back line and Tom Mercey joined the front row.
Saints were caught cold after barely a minute. Dan Hipkiss set up a ruck and Bath opened up the blindside for Tom Biggs to slip a deft grubber into the path of Abendanon who scored unopposed in the corner.
Barkley was wide with the conversion, his first miss out of 15 kicks this season.
A driving maul from the line-out forced a penalty which allowed Myler to kick for Saints on seven minutes but the fly-half's sliced clearance from the restart was not so composed.
Bath again used Hipkiss to take the ball up and Barkley slotted the resulting penalty.
Much of the next 10 minutes were spent trotting from line-out to line-out under the main stand as both sides sought territory.
Myler again narrowed the deficit to two points with a 35-metre kick on the quarter hour and put his side ahead for the first time with a 21st minute penalty after Ben Skirving infringed at a ruck.
Bath, although looking far more aggressive in the loose this season under new head coach Gary Gold, gave away a string of penalties, including one for dissent against Michael Claassens.
Abendanon made up for a spilled catch by immediately making a clearance on the other side of the field but Northampton continued to look the more composed side.
Yet another ruck offence by the home team just before the break was punished by Myler with his fourth penalty and Barkley hit the post with a 38-metre effort on the half-time whistle.
Bath replaced skipper Stuart Hooper with Dave Attwood early in the second half and the greater ballast helped win a penalty at the first scrum.
But it was Saints who injected real pace and urgency into the game away from the set-piece.
Unfortunately they lost Foden to an ankle injury following a man-and-ball tackle by Biggs who then saved a certain try but at the cost of a knock-on as he went for an intercept.
Myler added a fifth penalty for a scrum offence but that was quickly cancelled out by Barkley's boot at the other end after Tom May's kick was charged down.
When the Saints scrum folded again under pressure from the Bath eight, Barkley was on target again from 45 metres on the hour to pull the home side back to 15-14 down but Myler then missed from a similar distance.
The loss of Foden appeared to have taken much of the sting out of the visitors' attack but Barkley missed a chance to regain the lead, the ball dipping under the bar from nearly halfway.
Saints nearly grabbed a try when Barkley's clearance was charged down by Samu Manoa.
The lock regathered to feed Wood but the Bath defence scrambled back to deny the England flanker a try.
May then extended the lead to four points with a drop goal, leaving Bath four minutes to find a try to sneak victory but Saints held on and the home side had to be content with a losing bonus point.
- Olly Barkley