Resources for the Homeowner is a collage of resources, links, and other useful information for the homeowner.
Efficient Window Collaborative
- How to Choose Energy Efficient Windows
Window Ratings - Windows, Doors, Skylights
NFRC Assists You In Making Energy Efficient Window Choices
Hoffer Glass - Your Locally Owned NFRC Window Distributor
Energy Efficient Windows for Interior Alaska - Types and U Values
Energy Efficient Windows for Interior Alaska - Cold Climate Housing
The H Window
The H Window - Security Features
The H Window - Mini Blinds
Kolbe Teutonic Series Tilt-Turn Window
WHAT IS CONDENSATION?
As our fall days begin to get
colder and shorter, you may start to notice your windows sweating. This is condensation. When levels of
humidity in your home are too high relative to the cold temperatures outside condensation occurs. Signs
of condensation generally show first on windows because the glass is a colder, more visible surface.
With our bitter cold temperatures in Alaska many people notice condensation on their windows during the
winter months. Don't worry, this is normal. When you see condensation on your windows it actually
indicates that your new windows are highly effective in insulating your home. You new energy efficient
windows are designed to keep the warm in and the cold out. With this you must realize that moisture in
your home does not have the opportunity to escape and you home becomes more humid during the colder months
when windows and doors remain closed.
RECOMMENDED HUMIDITY LEVELS
-20° or colder
Not more than 15%
-20° to -10°
Not more than 20%
10° to 0°
Not more than 25%
0° to 10°
Not more than 30%
10° to 20°
Not more than 35%
20° to 40°
Not more than 40%
HOW TO CONTROL HUMIDITY
There are many things that you can do to keep your home's humidity level normal.
1. Know that the only way to stop condensation is to eliminate moisture in the air.
2. Regularly ventilate your house by airing out rooms daily, always use exhaust fans and vents when cooking, washing, and showering. Also, use them more frequently and for longer periods of time than you normally do.
3. If possible, open a window each day to let some fresh air in.
4. Store firewood outside.
5. Maintain your furnace and have it serviced regularly.
6. Turn on ceiling fans to circulate air.
7. Place plants in sunrooms or less-used rooms.
8. Waterproof basements using vapor barriers and/or waterproof floors, and moisture-sealing paints.
9. Use a dehumidifier.
If the problem persists you might want to contact a heating contractor about your excessive humidity.
WHAT CAUSES CONDENSATION?
Too much humidity in a home causes condensation on windows. There are many sources of humidity in homes such as; showers, dishwashers, washers and dryers, woodstoves, plants, pets, and people. Newly built homes are much more air tight and energy efficient than ever before. Because of this the warm air inside is being trapped (saving energy) and less outside air is brought inside (increasing humidity). Another reason newer homes may have increased humidity is because building supplies such as lumber, or plaster can release moisture for the first few years. Many older homes that did not have condensation before may notice it after replacing windows. This is because your new windows are much more airtight than the old windows. Because older windows are not as efficient they would allow air exchange, letting heat out and cold air in, which would dry out the moisture in the air. To measure your humidity levels you may purchase a humidity gauge, or a hygrometer at any hardware store. Too much humidity in a home can cause serious problems such as mildew, warping, paint failure, and deteriorating insulation.
GLOSSARY OF TERMS
Air leakage (Al) - Air leakage rating indicate the amount of air leaking in and out of a building through closed windows, doors, or skylights in the presence of a specific pressure difference. These rating are expressed in units of cubic feet per minute per square foot of a frame are (cfm/sq ft). The lower a window’s air-leakage rating, the better its airtightness.
Fenestration - The placement of window openings in a building wall, one of the important elements in controlling the exterior appearance of a building. Also, a window, door, or skylight and its associated interior or exterior elements, such as shades or blinds.
Gas fill - A gas other than air, usually argon or krypton, placed between window or skylight glazing panes to reduce the u-factor by suppressing conduction and convection.
Insulating glass - Two or more pieces of glass spaced apart and hermetically sealed to form a single glazed unit with one or more air spaces in between. Also called double glazing.
Low emittance (low-E) coating - Microscopically thin, virtually invisible, metal or metallic oxide layers deposited on a window or skylight glazing surface primarily to reduce the U-factor by suppressing radiative heat flow. Low-E coating are typically highly transparent to visible light but can reflect heat from infrared radiation.
National Fenestration Rating Council (NFRC) - A nonprofit, public/private organization created by the window, door, and skylight industry. It is composed of manufacturers, suppliers, builders, architects and designers, specifiers, code officials, utilities, and government agencies. The NFRC has developed a window energy rating system based on whole product performance.
Reflective coatings - Coatings on window glass that reflect radiation striking the surface of the glass.
Solar heat gain coefficient (SHGC) - The fraction of solar radiation admitted through a window or skylight, both directly transmitted, and absorbed and subsequently released inward. The solar hear gain coefficient has replaced the shading coeffient as the standard indicator of a window’s shading ability. It is expressed as a number between 0 and 1. The lower a window’s solar heat gain, the less solar heat it transmits, and the greater its shading ability. SHGC can be expressed in terms of the glass alone or can refer to the entire window assembly.
U-factor (U-value) - A measure of the rate of non-solar heat loss or gain trough a materials or assembly. It is expressed in units of Btu/hr-sq ft- f (W/sq m- C). Values are normally given for NFRC/ASHRAE winter conditions of 0 f (18 c ) outdoor temperature, 70 f (21 C) indoor temperature, 15 mph wind, and no solar load. The U-factor may be expressed for the glass alone or the entire window, which includes the effect of the frame and the spacer materials. The lower the u-factor, the greater a window’s resistance to heat flow and the better its insulating value.
Visible transmittance (VT) - The percentage or fraction of the visible (380 to 720 nanometers) weighted by the sensitivity of the eye, that is transmitted through the glazing.