I have a Fujitsu. It was operating fine for the cold weekend- except there was a small instance right when it hit around a -35 (windchill) I saw a red light blink for a few minutes on the wall mount then it went away. I have no idea what it meant, but my home stayed warm. Kept it at 72 from Thursday to Sunday. I haven’t seen the red light since. I do have baseboard as a back up, but I use my mini split only. Anyone know what Fujitsu is temp rates at? It’s an older model (at least 4 years old) is all I know about it