Mr_Destiny on 08 November 2018
Just added up the two-party vote in NC house races:
D: 50.7%, 3 seats
R 49.3%, 10 seats
That's 3 to 5 seats that would've gone to the Dems in a fairly-drawn map.
Note: 1 R seat was uncontested, so I used the vote from the most Republican district as a proxy.