I watched this a couple weekends ago and it is edge-of-your-seat suspenseful. Plus, it’s on Netflix. It’s not necessarily scary, but given the premise, it’s definitely unsettling.
Having the victim be deaf and mute certainly keeps things tense, but the characters are actually really well-written. In general, this is a horror movie where they’re smart, so you won’t be yelling at the screen, “Why would you go in there?!”. If you enjoyed this, you might enjoy Don’t Breathe (might).