Paradise CA Real Estate -Cal Green Building - Speaking Of Window Energy Efficiency - Paradise CA Homes
It has been said that a home loses 25% of it's heat through the windows. Windows should be viewed as a package really. That package is made of:
- The glazing; glass- including the coatings, gas and dual glazed spacer materials
- The frame; commonly - including wood, vinyl, aluminum or combinations of these materials
- The installation; vapor barrier, sealers and caulks
You have probably heard for sometime about the merits of Low-E glass coatings. In California you will find most Low-E glass units manufactured with one single outer layer of glass with the coating. This is to provide the greatest protection from heat and solar gain. Low E is also known for it's protection from UV, radiation and furniture fading.
In colder climates Low E coatings are said to have fewer advantages.
Photo: Butte Canyon Near Paradise Ca
Common glazing treatments
Low E II - Low E II features a double metallic coating on the inside glass surface to reflect or absorb the sun's warmth and reduce damaging UV rays. Offers enhanced U-factor and Solar Heat Gain Coefficient.
LoE--366-- Glass - Featuring three metallic layers of silver, this glass rejects solar heat and features a lower Solar Heat Gain Coefficient than Low E II. Recommended for warm climates where cooling costs are high and also for areas where intense exposure to the sun is an issue.
Argon Gas - An inert/ heavier than air gas. Primary benefit found in areas of the Country with extreme cold. Not believed to be as effective in warmer climates. Actual efficiency gained with Argon gas are believed to be in the 1 to 2% range. However numerous manufacturers are adopting the Argon gas filled units as a means to achieving Energy Credit Qualifications.
Triple Glaze - Features two layers of Low E glass with a clear center pane for a lower U-factor. Typically a feature found in colder climates.
Energy Star: Ratings or requirements differ by location nationwide. This is due to the distinct climate needs for your area.
Green Building: Programs differ, but generally "true" green programs require participants to exceed the minimum code or Energy Star rating for a particular area by 20%. One manufacturer states producing a window that exceeds Energy Star ratings by almost 50%.
The Language Of Window Efficiency
Understanding these common terms will help you select the right windows and doors.
U-factor - Most important number for cold northern climates. Rate of heat loss and how well a window insulates. The lower the number, the better a window is at keeping heat inside a building. The U-factor is key in the winter months, and important to consider in choosing a window.
Solar Heat Gain Coefficient (SHGC) - Most important number for hot/sunny southern climates. How well a product blocks heat from the sun. The lower the number, the better the performance.
R-value - Not used in measuring window performance. This measures resistance to heat loss. Many people are familiar with the R-value because of its use. It is generally accepted if a dual glazed window had an R-value prescribed it would be in the R 2- 3 range. That's quite low when you consider ceilings insulated today in the R30 to 38 range.
California Windows Simplified
- Purchase the lowest SHGC rating possible.
- Purchase the best Low E product possible.
- Frame materials will likely be a product of aesthetics and pricing.
- Argon gas etc. may become the product of ratings and rebates.
- U values are not at the top of our energy savings/payback list.
- When building Cal-Green review program guidelines to achieve program goals.
Phone: 530-370-1818 Email: steve@chainrealestate.net
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