Elias Yoder has reported:

Water running down a window on a winter morning may be condensation from moisture inside the home, rather than a fault with the window, Elias Yoder says in a video. He explains that a window is often the coldest surface in a room, so moisture in the air gathers there first. The glass shows where the water has formed; it does not produce the water.

Yoder says indoor moisture comes from people breathing, kettles and laundry drying on racks. A family of four can add a gallon of water to the air each day before anyone boils a kettle, he says, while drying laundry indoors is a major source that is often overlooked. Unflued paraffin or bottled gas heaters also release roughly as much water as the fuel they burn, he says, meaning an inexpensive heater can add moisture as it warms a cold room.

He recalls wiping a window one winter morning when his grandfather asked where the water came from. Yoder answered that it was the weather. His grandfather told him, “That is your own breath, and your mother's, and the kettle, and the washing on the rack.” Yoder says the condensation reflects the previous night’s indoor conditions.

Yoder also addresses his earlier advice on using less heat. He says lowering a home’s temperature does not reduce the amount of water in the air, but cold air can carry less moisture. As a result, water that was invisible in October may condense on the coldest surfaces in a cooler home.

The video describes clues homeowners can use to assess moisture. Glass that clears by mid-morning differs from water left standing on the frame, while black spots in a corner or behind a wardrobe can indicate mould on a cold surface with little air movement. A problem concentrated in one room can also provide a clue, Yoder says. A low tidemark, however, is a separate issue that requires a different trade.

His suggested steps include reducing moisture with pot lids and extractors, and keeping laundry in one room with its window cracked. He recommends brief, vigorous airing each day instead of leaving a window slightly open for eight hours. Moving furniture away from outside walls and opening curtains during daylight can help; closed curtains trap glass in a cold pocket.

Yoder cautions against closing off an unused room and leaving it unheated. It can become the coldest surface in the home, he says, and may develop a black wall and spotted mattress by the time someone opens it in March. If water is between the panes inside a sealed unit, he says, the seal has failed and household moisture measures will not fix it.

He asks viewers to check which room is worst before wiping the windows the next morning, then say which room it is and whether they dry laundry indoors. Yoder says he farms in Lancaster County, Pennsylvania, in a house with single-pane windows, stone walls and no heating system. His full collection and Amish home-saving method are at eliasyoder.com; he advertises savings of $6,000 a year. The video uses the hashtags #condensation, #damphouse, #windowcondensation, #mould, #winterhome, #homemaintenance, #heatingbill, #ventilation, #oldhouse, #amish, #homesteading, #damp, #coldhouse, #houserepair and #eliasyoder.