170 in a 100 year old attached rowhouse. Temp is between 65-68. About r38 I’m the attic with a lot of expansion foam to seal air gaps in the unfinished basement, ceiling, and wall penetrations.

16 year old 10 seer heat pump that’s properly charged and maintained. I use my ecobee to lockout my heat strips, upgraded to a demand defrost board, and monitor performance with beestat. My heat pump will maintain temp until the low teens.