This is a graph of the temperature inside our house from 2/15 12:00AM to 2/16 6:00PM. It was recorded by a piece of equipment in an upstairs closet, which is normally closed. The temperature inside of the closet is typically about 5°F to 7°F warmer than the rest of the house. It showed ~49°F the morning of 2/16, when our downstairs thermostat showed 44°F.

Some notes:

Inside of the equipment closet, our backup battery/UPS kicked in at the first loss of power and generated some extra heat for about 45 minutes until the battery drained. It recharged for an hour the next morning once power returned and ran for another 45 minutes when we lost power again, which slightly slowed the closets heat loss. We gave up and turned it off after that.

Our hot water heater (in the attic) burst shortly after power returned around midnight on 2/16 when the closet temperature was showing 51°F.

After noon on 2/16, the doors were opened and closed to the room and closet, which skewed the graph a bit when the outages were shorter and we started to build heat again.