Yes, CONVECTION is a Scrabble word!

Letter values in Scrabble US: C 3, O 1, N 1, V 4, E 1, C 3, T 1, I 1, O 1, N 1.

Is it a valid word?

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

the transfer of heat through a fluid (liquid or gas) caused by molecular motion
(meteorology) the vertical movement of heat or other properties by massive motion within the atmosphere