Is the electric baseboard heating powerful enough to heat an entire house?

Obviously! For instance, our heating system has just been fitted in a castle with very large rooms and a height beneath the ceiling of more than 5 m. After 2 days (time required to increase the temperature of stone walls of more than 1-m thick), we reached a temperature of 23°, which is the maximum temperature according to the specifications.
There is not better solution than the electric baseboard heating system to heat significant heights beneath a ceiling or a veranda. It makes it possible to stop the cold radiation from glazed surfaces.