Charles Ellicott Commentary Jeremiah 19:13

"and the houses of Jerusalem, and the houses of the kings of Judah, which are defiled, shall be as the place of Topheth, even all the houses upon whose roofs they have burned incense unto all the host of heaven, and have poured out drink-offerings unto other gods." — Jeremiah 19:13 (ASV)

Defiled as the place of Tophet.— A difficulty affecting the construction, but not the meaning, of the passage makes the rendering as the place of Tophet the defiled preferable.

Upon whose roofs they have burned incense.—The flat roofs of Eastern houses were used for exercise (2 Samuel 11:2) and also for prayer and meditation (as in Peter’s vision at Joppa, Acts 10:9). Furthermore, from Zephaniah 1:5, they seem to have been specially chosen, as was natural, for worship addressed to the host of heaven.

The two altars “on the top of the upper chamber of Ahaz” (2 Kings 23:12) were probably so situated.

Where people had been accustomed to keep the holy days of the Feast of Tabernacles (Nehemiah 8:16), they had celebrated their idolatrous rites .

So Strabo (xvi. p. 1, 131) describes the Nabataeans as worshipping the sun and offering incense on an altar on the roofs of their houses.