Related questions on Metaculus:
Will Republicans win both the House and Senate in 2022 midterm elections?
How many seats will Democrats win in the US House of Representatives in 2022?
In 2020, Republicans gained seats in the House of Representatives despite losing the Whitehouse, leaving the Democrats with the thinnest margin in decades. Historically, there is often a backlash against the winner of the presidential election during the first term, so majority control could flip. However, redistricting following the 2020 Census will have its effect too.
If Republicans win 218 seats or more in 2022, they will secure a majority in the house.
435 seats will be contested in 2022 (most in November, but some runoffs are possible). The question resolves after enough races have been called by reliable media reports to give a majority to one party or another. In case of ongoing ambiguity, the question can resolve when the Congress convenes in January 2023 and certifies its membership.