tolbiny wrote:
Is it unsafe to install a dimmer switch on the average dining room ceiling
light if the house is older and has aluminum wiring?

Probably is unsafe if the dimmer has copper wire leads that have to be
wire nutted to the Aluminum wire. Dimmers create resistance which
raise temperatures which cause aluminum wire to fail. Make sure
whatever you install is rated for Aluminum wire.

Read up and change the batteries in your smoke detectors

http://www.inspect-ny.com/aluminum/aluminum.htm