A few years ago, we found bed bugs in one of our bedrooms.
We caught it early on, and one bomb and one fogger were enough to deal with the problem.
I kinda took for granted the fact that heat and light would fade the chemicals away, but would like to know what people who know about chemistry think about it. Is it possible there is still chemicals on the walls? I will need to turn the heater on soon, and find myself worrying it might be bad for us to turn it on if there are still chemicals on it.
"A few years" should be more than sufficient to have most traces of any volatile chemical residue removed. The caveat of "residue" is that one can almost never remove traces of compounds completely - it is just a matter of how sensitive your detection methods are. However, "SAFE" levels of residual compounds are determined fairly carefully. Proper use of something like a bed bug fogger (including post-use airing and cleanup procedures) should result in a human-safe environment.