It's a bold claim, but one backed up by a survey of 2,008 respondents, some of which I'll share below. For more see the link from the Barna Group.
In my prior, short brushes with house churches, the main complaint I received from my institutional church brothers and sisters was how such churches are perceived to be glorified home bible studies -- that without educational programs, staged worship, and stricter discipline, house churchers would burn out or become bored with the weekly routine. This now-famous survey, however, paints a more realistic picture of what I've observed.
The typical house church gathering lasts for about two hours. [...]
93% have spoken prayer during their meetings
90% read from the Bible
89% spend time serving people outside of their group
87% devote time to sharing personal needs or experiences
85% spend time eating and talking before or after the meeting
83% discuss the teaching provided
76% have a formal teaching time
70% incorporate music or singing
58% have a prophecy or special word delivered
52% take an offering from participants that is given to ministries
51% share communion [...]
Most house churches are family-oriented. Two out of every three house churches (64%) have children involved. Those churches are divided evenly between those who have the adults and children together throughout the meeting (41%) and those who keep them separated (38%). The remaining churches divide their time between having everyone together and having time when the children and adults are separated.
Another Barna Group survey a year earlier shared an estimate that 70 million American adults had attended a house church meeting and roughly 20 million participated in a house church from week-to-week. One wonders how much these numbers have shifted in a decade.