You can get a good idea by reading the instructions for installing the
factory A/C at http://tinyurl.com/ysylw. This is for the 1999 model, so
it is not the same as yours, but it should give you an idea about the
level of complexity.

http://www.hparts.com used to have the more recent installation
instructions, but that site now says "Under Construction". Perhaps if
you try back later in the week you can find the correct instructions for
your car.

Pie wrote:
>
> I am super paranoid about having work done on a new
> car by non-dealer mechanics, so I was curious about
> how invasive a procedure is to add an AC to a
> Honda Civic 2004.
>
> Do they have to take the guts of the car out to
> put it in, or it is an easy add on that a reasonably
> skilled mechanic can do it without screwing something
> else up in the process? And how much usually this procedure
> cost (if anyone out there has experience with it).
>
> Thanks a lot in advance.
> Ben