A condensation and surface-spot observation log: fixed positions, a fixed morning time, a photo with a grid, and the dew point beside each entry

Goal

Keep a dated record of where condensation appears on windows and where dark spots appear on walls, sills and frames, with the indoor conditions beside each entry, so that changes over weeks and their timing relative to ventilation and weather are seen rather than remembered.

Prerequisites

The National Weather Service explains the dew point as the temperature to which air must be cooled to reach 100 % relative humidity, and states that if the air were cooled even more, water vapor would have to come out of the atmosphere in the liquid form; a pane colder than the room's dew point is the household case. The EPA's mould and moisture guide states that condensation can be a sign of high humidity. Needed: a thermometer-hygrometer, ideally one that displays dew point (otherwise the dew point is computed later by a formula named in the header); a phone camera; a grid or ruler for scale; positions marked with small tape tabs.

Steps

1. Header: each position with a number and a description ("kitchen window, bottom left pane"), the room, the outside wall's orientation, and the instrument's placement.
2. Choose one time each morning before windows are opened and log at that time only.
3. Per entry: date, time, indoor temperature, relative humidity and dew point at the instrument, outdoor temperature from a home sensor or a named station, and the previous evening's ventilation and moisture events (shower, cooking, laundry drying, window open and for how long) in a fixed vocabulary.
4. Per window position: condensation as none, edge only, partial or full pane, and its height above the sill if partial.
5. Per surface position: a photograph with the grid or ruler in frame, from the same distance and angle, and the visible extent of any dark spot as estimated length and width in cm. Describe colour and texture plainly; do not name a cause.
6. Add a row whenever something changed at a position (cleaning, painting, furniture moved), so that a break in the series has a reason.

Expected result

A per-position series of condensation levels and spot dimensions with dew point, outdoor temperature and ventilation beside each entry, and a photo series that can be laid side by side.

Limits and test basis

Proposed protocol; no cause, growth rate or relation to ventilation is claimed. Dark spots are recorded as seen; the log does not identify them as mould, dirt or staining and gives no guidance on health, cleaning or building repair. A dew point computed from a consumer hygrometer carries its humidity error. Different lighting exaggerates or hides spots; a fixed lamp reduces that but does not remove it.