Remember
Windows do not cause condensation.
Excess interior humidity is the source.
Windows don’t
manufacture water!
Everything you need to know about
condensation.
Diagnosis:
It is difficult to completely eliminate moisture on
existing windows. Inefficient windows (e.g., single pane with aluminum frames) or high moisture with inadequate ventilation
can result in condensation, frost, or pools of water on windows and sills. Moisture in the air condenses when it touches a
cold surface. (The same effect causes a glass of ice tea to "sweat" on a hot humid day.) Continued excess moisture
can lead to mold, mildew, and deterioration of your windows and sills.
Of course windows don’t manufacture water. If you were out in the desert,
you’d want a canteen, not a window.
But people seem to believe that windows manufacture water. They call up window contractors and say.
“my windows are all wet, and it’s the fault of the windows. I never had condensation before.”
Well, not quite.
Water on windows is condensation and it can be a problem and it has a solution. But it’s
not a window problem and the solution doesn’t come from the window.
What causes window
condensation? What can you, the homeowner, do about it? More and more homeowners
are concerned about growing condensation problems... and they are growing. There are several explanations for
this last remark. For the most part, the problems can be traced to “progress”.
For example, the “tight” construction of newer homes...increasing use of modern labor saving appliances...certain
building materials...smaller homes...more gas furnaces...more showers.
A little fog on the
corners of your glass shouldn’t bother you. And it probably doesn’t. But
“problem” condensation, fog or frost that covers whole windows, definitely bothers you. And
it should. The visible effects are just the tip of the iceberg. What is happening
elsewhere in your home? Take your attic. Excess moisture may be freezing in the
insulation where it will later melt and damage your plaster. Or perhaps it’s forcing its way out
through your siding, where it will form blisters under the exterior, or it may be promoting mildew in your home.
The
culprit is too much water vapor. Not the window, not the insulation, not the paint. The
only answer is to get rid of excess water vapor. Water vapor, or humidity, is one of the invisible
components of air. This humidity tries to flow toward drier air, since this air has a lower vapor
pressure. In other words, the higher vapor pressure in moister air forces the moisture to areas which are
drier.
In cold weather, the air outside is generally drier than within a warm house. What happens, then,
is that the moisture is forced to the outdoors. The most obvious indication of this is condensation on
your windows: the moisture comes in contact with the cold surface of the glass. It therefore
condenses to form either frost or water (depending on whether the temperature of the glass surface is below or above 32°.
The “tight” construction of modern homes traps the moisture in many ways. Certain varnishes,
tiles, plastics and acrylics—which are increasingly used in construction—do not allow moisture penetration.
Thus the moisture created by kitchens, laundries, bathing and human bodies (as well as cat, dog and other pet bodies)
can’t flow easily to the outside. Insulation and construction materials that are designed to keep
cold air outside also keep moisture inside, further increasing the moisture level in your home.
In simplest terms,
condensation is simply moisture build-up on a material that is below the dew point temperature of the surrounding air. If
the glass goes below that temp - you have condensation. If it doesn't then you don't.
How to further decrease the chance of condensation occurring on the interior
of your window
Want more from your windows?
Ask
for ENERGY STAR.
Energy
Star rated energy efficient windows will further cut down the creation of moisture on the glass by raising the interior
glass surface temperature in wintertime. However, if a home continues to have excess
humidity, new windows will not eliminate the humidity; only diminish the possibility of condensation occurring on the glass.
ENERGY STAR qualified windows, doors, and skylights save you energy and money,
increase the comfort of your home, and protect your valuable possessions from sun damage. They are also better for the environment
because lowering your energy use means less air pollution from power plants.
·
Save money and energy. Replacing single-paned windows with ENERGY STAR qualified windows or
choosing ENERGY STAR over the typical clear-glass double-paned alternative can save a significant amount of money on your
energy bill.
· Say
goodbye to winter drafts,reduce the risk of sweating and lower the inside temperature of the glass in the summer sun.
Thanks to a host of new technologies including Super Spacer, ENERGY STAR qualified
windows, doors, and skylights keep your home cooler in the summer and warmer in the winter, making you more comfortable year round.
·
Protect your home's interior. Many ENERGY STAR qualified windows, doors, and skylights
act like sunscreen for your house, protecting your photographs, artwork, furniture,
carpets, and wood floors from sun damage.
· Buy
with confidence. Every ENERGY STAR qualified window, door, and skylight is independently
certified to perform at levels that meet or exceed strict energy efficiency
guidelines set by the U.S. Department of Energy.
·
Ask for ENERGY STAR. To purchase the most efficient window for your home, ask for products
that are ENERGY STAR qualified in your Climate Zone. To learn more, see the window purchasing
tips on the following website:www.energystar.gov.
· Seal
and insulate with Home Sealing. Sealing your home's envelope is one of
the most cost-effective ways to lower your home's energy bills and improve your comfort.
What's in a pane
- or two?
All energy efficient windows have at least two panes, but
not all double-paned windows are energy efficient. Twenty years ago, double-paned meant energy efficient; today, advanced
technologies have enabled the development of triple glazed windows that are much more efficient than traditional clear-glass
double-paned windows. For maximum energy savings, count on ENERGY STAR.