The temperature inside an apartment or house without any heating turned on at night will depend on various factors such as insulation, outside temperature, building materials, and air leakage. However, in general, the indoor temperature can be expected to be a few degrees warmer than the outside temperature.
Insulation plays a crucial role in retaining heat and preventing cold air infiltration. Well-insulated homes will retain more heat and have a smaller temperature difference compared to poorly insulated homes. Similarly, factors like the size of windows, their quality, and the presence of drafts or air leaks can affect the temperature difference between inside and outside.
In colder climates, the temperature difference between the inside and outside can be significant, possibly ranging from 10 to 20 degrees Fahrenheit (5 to 11 degrees Celsius) or more. In milder climates, the difference may be smaller, typically around 5 to 10 degrees Fahrenheit (2 to 6 degrees Celsius).
It's important to note that these are general estimates, and actual temperature differences can vary based on specific circumstances.