lights dimming when the A/C comes on is normal. she may not have had this problem at her old house because it had a smaller A/C unit, a larger power main, or was closer to the power company transformer. one way to reduce dimming is to install a hard start kit on the compressor. it is basically an additional start capacitor. it kick starts the unit and get is running faster. since the compressor gets up the speed faster, the the duration that the voltage is low is decreased. therefore dimming of the lights is less noticable
