Adam Clarke on Acts 20:8

Upper chamber - It was in an upper chamber in the temple that the primitive disciples were accustomed to meet: on that account, they might have preferred an upper chamber whenever they could meet with it. The pious Quesnel supposes that the smoke, issuing from the many lamps in this upper chamber, was the cause of Eutychus falling asleep; and this, he says, the apostle mentions, in charity, to excuse the young man's appearing negligent.