According to the United States National Park Service, a medium-sized barn with sufficient extant windows where the internal volume can be near completely utilized can allow for a successful and historically responsible conversion of a barn.
[1] While not a new phenomenon, barn conversion became quite popular in the waning years of the 20th century.
For a barn to be comfortable as a home walls often have to be insulated and refinished and the interior volume of the space must be greatly reduced.
[1] The barn's site itself is often altered by the addition of close-in, driveway parking and residential landscaping.
Some barn conversions go so far as to dismantle the entire original structure, discarding the exterior and simply reusing the internal structural supports on a new building.