Aluminum Wiring! This sucks.
Leenders... just to check something... do you mean all the circuits are aluminum, or do you mean that you've looked in the panel and saw 'some aluminum'?
Service cables are often aluminum. I'm re-wiring my 1950 house (was run with romex with no ground), and I ran brand spanky new aluminum to my new panel, and may also run aluminum for my one 'big circuit' - range (haven't decided yet, thinking about doing a 60A capable circuit for the future, might run it in conduit) even though I am running copper for everything else.
My understanding is that aluminum is not a problem when using A.) terminations that are rated for it, B.) larger cables (i.e. not for 15A & 20A circuits) and C.) anti-oxidant paste.