It is input decoding which matters here. There is no way to convert incoming data to UTF without treating the original encoding of each individiual input. The issue with harvesting from different sites is that the encoding of these sites can be 1) different and 2) just broken for a few of the sites.
Your code snippet s/\x{00A0}/ /gm; just works if all input has been properly decoded into to Perl's "character" semantics (I avoid to call it UTF-something because this is misleading), protected by the error handling of the Encode module.
Of course, you need to encode your output, too. binmode(STDOUT, ":encoding(utf8)"), converts Perl's characters into a valid UTF-8 stream.
