For the past four nights one of my smoke detectors (one of the fancy dual sensor ionization/photoelectric kind) has been beeping in the middle of the night. Each morning I replace the battery and everything seems fine, until the house gets cold, and then the thing starts beeping again . . . yesterday I went out and bought MORE new 9V batteries . . . still same problem.

So I finally called the company BRK/First Alert.
I always take notes during and/or after these kinds of calls . . . here they are:

Just called BRK about my First Alert SA710 smoke detector (only 2 years old) chirping when the house gets cold at night, even with brand new battery. Only happens at night.

They gave me some crap about how the batteries must be certain brands and dates (Energizer, Duracell, post-2014). (Have already tried those as well as Rayovac, nothing works.)

They are willing to send me a new one for $6.99 S&H. For that I can by a new, cheaper SD that won’t eat batteries and will work correctly.

Only valuable info was how to discharge after removing battery (so it stops chirping): push button and hold for 20 sec

I should also note that this particular unit has gone through batteries much faster than any of my other smoke detectors (the others are Kidde and Universal brands).  This issue is particularly annoying to me because even though my house is very small (about 1000 sq ft), I was required to install additional smoke detectors when I got a couple of new windows . . . so I now have 3 (THREE) plus a CO detector upstairs and 2 on the first floor and 2 plus a CO detector in the basement . . .

Ah, Minnesotans, they love laws and rules and regulations . . .