Older homes were built drafty. Moisture and dryness traveled evenly and directly through the exterior walls. It’s just the way homes were built back then. With time and progress, today’s builders construct a much tighter home envelope. Changes in home-building techniques bring about a new set of dynamics, one of which is excessive humidity and its effects, called condensation. Humidity is measured in terms of a percent and is referred to as “relative humidity” or RH. Relative humidity is the combination or sum of all sources that produce or create moisture. Merely living and breathing in your home adds moisture to the air. Some examples that naturally create humidity and moisture in a home are:

• Showering and/or bathing

• Washing clothes

• Dishwasher

• Cooking

• Cleaning

• Plants

• Pets & fish tanks

• Breathing

This humidity vapor mixes with the warm air being distributed throughout your home by your furnace making it feel warmer to your skin. Water vapor travels with the warm air and is naturally attracted to cool or cold surfaces. Some people find more moisture helps prevent shocks from static electricity. Interior humidity is directly related to the exterior temperature so you should be monitoring the RH level in your home daily. Simple gauges are sold in the thermometer sections of local stores that can take this measurement for you. Per the Harvard School of Public Health, “An interior relative humidity at 40% or higher is undesirable in the winter.” It is very common to observe window condensation and/or icing caused by water vapor. Water vapor is invisible to the human eye, but its effects can be seen. Air circulation helps distribute the water vapor and lessens the opportunity for vapor to stop, cling and collect causing condensation on windows. The constant use of a ceiling fan on low can help create this air circulation for you. Also, keep blinds pulled up slightly from windowsills and ledges to allow the air to circulate at the window. Keeping blinds closed will cause even more condensation to collect on windowsills or ledges. If condensation appears it should be wiped away.

NOTE: Some window blinds may enhance the condensation factor. One of the higher culprits to this is the recess-mounted “pleated” style blind due to the polymer coating it has. This helps trap the moisture against the cooler surface of the glass.