Very effective home remedies for any burn, including sunburn are milk, or vinegar.
Dilute vinegar with water, dip a soft clothe or gauze into the solution, and apply as a compress, will take the "fire" out. The same maybe done with milk. Gently, do not rub as you may damage the skin. Keep showers or baths a cool temperature. Never put a heavy ointment, or butter on a burn, as it will trap the heat in even further, as well as lotions. Apply aloe vera gel as needed, it will cool the burn, and not trap the heat in.