Indoor humidity levels are a key indicator as to the health of your home. Too little and your skin can dry out, lips will chap easily and the wood in the house can over dry and crack. Too much much moisture and your house or at least parts of it can become a breeding ground for molds. There are several ways to check the indoor humidity levels in ones home. Below are a few ways and some suggestions to keep it in check.
One of the simplest ways to help determine if you have high humidity levels in your home is to look at your windows from the interior. During the winter season your windows will get condensation forming on them. The amount will vary depending upon the temperature and the dew point. The higher the levels of moisture in the air the more likely that moisture will condense on the windows. This occurs because the windows (being not very good insulators) will be colder and this sets up the condition for condensation to form. Single pane windows will easily get condensation and are not as reliable to help determine moisture levels. Double pane glass that has condensation is a good indicator of high levels of moisture is in the indoor air.
Another way to look for high moisture levels involves a little work. Get a ladder and take a look in to the attic space. If you are doing this during the winter time take a look at the points of the nails that are sticking through the roof sheathing. These nails will conduct the colder temperature from the exterior. Look for drops of water forming on the nail points. If you see some immediately upon getting in the attic then there is high moisture levels. This needs corrected.
Attic spaces need to have a good amount of ventilation. The proper amount of ventilation will not only help keep the attic temperature down during the summer, it will also allow moisture to exit to the exterior and prevent the buildup of moisture which can result in mold and damage roof sheathing.
Another situation that I often find as I conduct home inspections is the shower fan vents being routed or terminating in the attic space. This greatly increases the moisture levels and speeds up any mold growth or wood deterioration in the attic spaces. If this is the case in your home it should be improved so that the duct terminates on the exterior of the home.
There are also several other things to look for and to consider. If unsure contact a home inspector that is able to focus on these things for you.