FIRST OFF, CHECK YOUR BATTERIES, THEY MAY NEED TO BE REPLACED. MOST NEWER HOMES OR THOSE RECENTLY REMODELED WILL HAVE LINKED SMOKE DETECTORS. THESE ALL SOUND OFF SIMULTANEOUSLY, EVEN WHEN ONLY ONE UNIT DETECTS SMOKE. IN MOST CASES, REPLACING THE BATTERY FIXES THE PROBLEM. MANY “HARDWIRED” OR 120 VOLT UNITS WILL HAVE A BATTERY BACK UP, SO TRY THIS FIX EVEN FOR HARD WIRED SMOKE DETECTORS. IF ALL ELSE FAILS, GIVE US A CALL!!!!