Why do my lights dim when A/C turns on?

The light flickering problem can be caused by several things, but most probably due to loose or improper neutral connections. The browning out effect is due to voltage drop caused by an increased load on the phase conductors. If the system were properly wired, the browning effect would be minimal, and hardly noticed. When a load imbalance occurs (a 120 volt appliance starts) the increased resistance caused by loose or improper neutral connection is magnified, in extreme conditions the lights will flicker as the connection begins to fail. Your wiring should be thoroughly inspected starting at the incoming service conductors and continuing through each outlet or junction box to insure that a proper neutral path has been established for each circuit, and that all connections are tight.

Why do my smoke detectors alarms go off for no apparent reason?

Many smoke detectors run using a battery. When the battery gets low, your smoke detector may alarm to get your attention, warning you its battery is running dry. Smoke detectors should be tested frequently, and batteries should be changed at least once  year. One of the most common cause of nuisance alarms on home smoke detectors is dust. Consider using a vacuum cleaner attachment on the unit. A can of air can work well too.