The proud dad – who recently made his return on The X Factor as head judge – said his son's arrival has brought more 'colour' to his life.
In an interview with the Mirror he said: "It definitely feels more like a home. There's more of a nice atmosphere.
"It's definitely louder. Not to the point where everybody thought I was going to be getting up at five in the morning and all that kind of stuff."
The 54-year-old - who became a parent for the first time on Valentine's Day when his girlfriend Lauren Silverman gave birth to little Eric, added: "He's been a very, very happy baby. The other night I heard him cry at 4.30 in the morning so I went up to see him and within five minutes he was back to sleep, happy again. Definitely a happier house."
In recent months, Simon has used Twitter to share pictures of himself with his eight-month-old baby boy.
Over the summer, he shared a cute picture of his son sat on his lap in matching sunglasses as himself, he captioned the lovely image: "Taking after daddy."
In a previous photo, Eric can be seen sitting in a bath-seat as he gazes up at his dad, while Simon tenderly gives him a little wash.
Simon recently revealed how he is eager to have another child with his American girlfriend, telling the Sunday People: "Of course I'd like another child. You have one, and I'd always have another."
Simon made his comeback on The X Factor panel this summer, alongside returning judge Cheryl Fernandez-Versini, former Spice Girl Melanie Brown and music manager Louis Walsh.