All air contains a certain amount of moisture, even indoor air. Many household items generate indoor humidity such as your heating system, humidifiers, cooking devices, showers and baths, and more. In fact, every activity that involves water – yes, even mopping the floors counts – can contribute moisture to the air.
Condensation is much more likely to occur in homes where January temperatures typically drop below 35oF because there are greater temperature extremes affecting the glass in the home.
Additionally, it is very normal to experience condensation at the start of each heating season. During humid summer months, your home absorbs moisture and then “sweats” when you turn on the heat. This is no cause for concern – it is only temporary. After the first few weeks of heating, your home should be dried out, and condensation reduced or eliminated.
If you have recently had some remodeling or construction complete, you may notice a similar thing. Due to the high levels of moisture in wood, plaster, and other building materials, your home may temporarily sweat during the first few weeks of the heating season.
Another factor in condensation is technology. With today's modern insulation, moisture-barrier materials, and air-tight home construction, energy-efficient homes are possible. These homes, however, effectively keep the cold out, but trap moisture in the home, producing higher humidity levels and more condensation.