Polls are predicting that Democrats will most likely keep control of the House of Representatives in the election. In order for Republicans to gain control of the House, they would need to have a net gain of 21 seats on November 3rd, which is highly unlikely.
Of the 435 seats, 44 of the races are being considered competitive, of which 27 have a Republican incumbent and 16 have a Democratic incumbent, and one has an independent. According to the Economists polls, Democrats are projected to win 244 seats and Republicans are projected to win 191 seats.
The US House of Representatives is responsible for making and passing federal laws, impeachment of the President, and electing the President in the event of an electoral college tie.