i got one out, killed one and escorted the other out the front door this morning.
we had bees in the house a few years ago, only it was 15-20 a day! they had built a nest under the eaves in the back of the house by the tv room, and were getting into the house via a closet.
That is the room we are currently renovating, and i can ABSOLUTELY see why that was happening now that all the interior walls are down.
I would check near the windows in the evenings and mornings - that's when you are most likely to find a nest because they are all leaving and coming home at the same time.