Smoke Detector Beeps Twice A Day

I haven't run into your situation and I don't know your brand or model. They may just need interfering dust blown out of them. But, basic detectors only beep by themselves if the battery needs replacing. I suggest taking down a (or more) detector down and find out what the brand and model is, so you can possibly find an Instruction or Owner's Manual to decipher the beeps.

- It may turn out that you have Dual Detectors that also monitor Carbon Monoxide and the beeps are signaling replacement of the entire unit (they're quite short-lived devices). Or, they may be actually picking up something when the water heater, furnace or clothes dryer run. Call in a Professional.

- Finally, you may be dealing with hard-wired detectors that just have a backup battery, which may need replacing at some or all of the units. But, these too may be signaling replacement of the units or an electrical problem. Some setups use a Transformer in a low-voltage arrangement and that Transformer may be cutting out as it heats up and needs replacement to stop the beeping.