An app can't do windows, but that day is coming.

Savan Kotecha spent about $80,000 to modernize his 2,400-square-foot West Hollywood, Calif., home. Mr. Kotecha, a 34-year-old songwriter and vocal producer on Simon Cowell's "The X Factor," is an admitted "Apple freak" who uses an iPad app made by home-automation company Crestron.

"It...