Caley hit the woodwork four times but boss John Hughes was not too disappointed to be held by the Scottish Premiership's bottom club.
It leaves Hughes still searching for his first home win as Inverness boss since taking over in December.
"We hit the woodwork four or five times," said Hughes. "We could have won the game comfortably and on another day we might have.
"I felt in terms of the style we wanted to play, everything was there. We passed it and mixed it up well. The shape and energy was very good.
"We had a couple of efforts cleared off the line and the goalkeeper has made two or three great saves.
"I cannot be too disappointed because there were a lot of good performances out there."
Hearts manager Locke said the result proves his team are making progress - they were beaten 2-0 on their last visit to Inverness.
"We came up to Inverness earlier in the season and got beat 2-0 where Inverness outplayed us," he said.
"You can see there's been a big change in the players, especially the younger ones who have come on a lot.
"It was difficult today with the conditions and I felt Inverness had the better of the first half but we had the better of the second.
"The players have shown determination all season long and you can see that where we might have made mistakes over the course of the season, we're not making as many now.
"All in all I think the draw was a fair result."