0 C is 273.15K, so room temperature is around 295 K. 300 K is a decent approximation to make back-of-the-envelope calculations easier, but I don't know anybody

0 C is 273.15K, so room temperature is around 295 K. 300 K is a decent approximation to make back-of-the-envelope calculations easier, but I don't know anybody that actually keeps their room at 80 F.