Weird - I also listened to ambient music for almost a decade before hearing about Tim Hecker. I have to second the recommendation, although I started in a different place - when I first heard Harmony in Ultraviolet, it was like something clicked into place. Ambient music had been missing something and I hadn't even known it.

I had a similar experience with Abul Mogard. Whoever they really are is a genius of immense soundscapes.