Yes, HEIGHTS is a Scrabble word!

Letter values in Scrabble US: H 4, E 1, I 1, G 2, H 4, T 1, S 1.

Is it a valid word?

HEIGHTS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a high place
the vertical dimension of extension; distance from the base of something to the top
the highest level or degree attainable; the highest stage of development
(of a standing person) the distance from head to foot
elevation especially above sea level or above the earth's surface