Plenty of fans criticised the club's new base during the 2016-17 campaign, with many accusing the high-tech structure of lacking atmosphere.
The team were unable to play in the stadium during the month of August due to the World Athletics Championships being staged at the Stratford venue.
The East London outfit returned to the ground on Monday evening when they sealed a 2-0 win over Huddersfield Town - their first Premier League win of the season.
"The stadium I said last year that our performances in the second half of the season, apart from a couple of games, we have improved our performances," Bilic told Sky Sports News.
"We have played some really good games here. We are feeling now like this stadium is our proper home. It will never be Upton Park of course but it is becoming our home more and more. It is my birthday today and this is a great, great present for me."
The Hammers have now moved from the bottom of the league table to 18th following Monday's win.