United went ahead through defender Gavin Gunning's second-minute header and looked to be on course for a first SPL home win since August. But Brian McLean's own goal two minutes after the break proved enough to earn Steve Lomas' Saints side a point.
"It was a very open entertaining game for the supporters but it's hard work being Dundee United manager," said Houston.
"I think we're playing some really good stuff and we're attack-minded but, in the same breath, we're not killing teams off.
"Gavin Gunning could have had a hat-trick of headers in the first-half.
"Rudi Skacel had a chance as well which was cleared off the line while at the same time Radoslaw Cierzniak had some good saves as well.
"I felt with the chances we had we could have been comfortably ahead at half-time."
Saints boss Lomas admitted a lack of cutting edge meant his side ended up drawing their fifth game in their last eight outings.
He said: "If we were a bit more clinical we would have gone down the road with three points.
"The performance was good but the conversion rate of chances to goals must be the poorest in the league. That's what's causing us to draw so many games."