No I am not commenting on the supernatural here, we are talking about the mysterious stains that appear inside of homes. This “Ghosting” tells a story of poor insulation and leaky drafty homes.
When insulating attics, is it best practice to completely cover the ceiling framing to reduce thermal bridging. The wood conducts heat much more readily than the insulation and this makes parts of the ceilings cold in winter.
Indoor air pollution can cause these stains as they tend to stick to the cold surfaces in our humid heated homes. One major contributor to these stains are candles and fireplaces. Combustion appliances water heaters, furnaces, pilot lights that are poorly adjusted or vented incorrectly may also cause these. Smoking, cooking grease, and dust particles all may be attracted to the cold surfaces. In most modern construction there is a central air return to the furnace.
The air furnace blower forces air in the rooms and that same amount of air has to leave the room. Most of it usually flows out the door and to the cold air return. If the door is closed and you have carpeting it can filter the air and leave stains. There should be a gap under the door to allow the air to flow freely.