Michigan State University Extension
Home Maintenance And Repair - 01500316
06/24/03
Moisture On Windows
Your humidistat is set too high if excessive moisture
collects on windows and other cold surfaces. Excess
humidity for a prolonged time can damage walls especially
when outdoor air temperatures are very low. Excess
moisture condenses on window glass because the glass is
cold. Other sources of excess moisture besides overuse of
a humidifier may be long showers, running water for other
uses, boiling or steaming in cooking, plants, and drying
clothes indoors. A tight, energy efficient house holds
more moisture inside; you may need to run a kitchen or
bath ventilating fan sometimes, or open a window briefly.
Storm windows and caulking around windows keep the
interior glass warmer and reduce condensation of moisture
there.
Humidifiers are not recommended for use in buildings
without proper vapor barriers because of potential damage
from moisture buildup. Consult a building contractor to
determine the adequacy of the vapor barrier in your
house. Use a humidity indicator to measure the relative
humidity in your house. The American Society of Heating
and Air Conditioning Engineers (ASHRAE) recommends these
maximum indoor humidity levels.
Outdoor Recommended Indoor
Temperature Relative Humidity
----------- ------------------
+20 F. 35%
+10 F. 30%
0 F. 25%
-10 F. 20%
-20 F. 15%
This article was written by Anne Field, Extension
Specialist, Emeritus, with reference from the Association
for Home Appliance Manufacturers.
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
MSU is an affirmative-action, equal-opportunity employer. Michigan State
University Extension programs and materials are open to all without regard to race,
color, national origin, gender, gender identity, religion, age, height, weight, disability,
political beliefs, sexual orientation, marital status, family status or veteran status.
Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in
cooperation with the U.S. Department of Agriculture. Thomas G. Coon, Director,
MSU Extension, East Lansing,MI 48824. This information is for educational
purposes only. Reference to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not mentioned.
This file was generated from data base 02 on 02/04/08.
Data base 02 was last revised on 06/24/03.
For more information about this data base or its contents please contact
strausc@msu.edu .