It doesn’t matter who has the largest number of members in the House of Representatives—it matters how many states they have a majority of members in. Each state casts one vote. If a state is evenly split, they won’t vote for either candidate. I think there are more than 30 state delegations where the Republicans have an absolute majority, but haven’t checked against the 2016 election results (they lost a few seats).
I just looked at the RCP list for the House of Representatives winners in 2016. The GOP would have 30 votes at least. Louisiana still has 2 undecided races, so the GOP could wind up with 31 votes.