Yes, heft is a Scrabble word!
...and is worth 10 points in Scrabble, and 9 points in Words with Friends
heft
Verb
1. Lift or elevate
2. Test the weight of something by lifting it
Noun
1. The property of being large in mass
What Scrabble words can I make with the letters in heft?
3 Letter Words
2 Letter Words