I was recently called upon to check some problems with a one year old upright piano in Manhattan. The owners said that another technician had been there and the problem had returned in a very short space of time. This piano had a cracked soundboard, loose tuning pins and hammers that were hitting each other rather than the strings. I was surprised at the damage due to the fact that this was a quality instrument made in Japan. Upon further examination I saw a metal grill under the piano, as I put my hand next to it I could feel a blast of hot air from it. The heat from the vent had literally overheated the piano and dried it like a piece of toast.
Pianos do not like heat of any kind! Dry heat will destroy them in a very short time. Make sure you leave some space between any heaters and a Piano. And worst of all, the manufacturers warranty most likely wont cover the damage.