I live in an apt building in the 60's. I always notice that the room is always warmer than the outside in the winter time(even with no heating). This stays true in the summer time where it would be 65 outside at night and somehow the room can stay in the low 80's(if I leave A/C and ventilation off).
Does this indicate a well insulated apt?
It is really easy to warm up my apt with a cheap $20 electric heater in the winter. I would go from low 40's to 70's with the heater on full.
However, in the summertime, my window A/C unit struggles to even get the room to the low 80's. Granted, I am on the 2nd floor and have windows facing the sun most of the day.
Is it just a weak A/C, lack of airflow?