Green Home

Windows

A worthwhile energy saving investment, new windows can make a huge difference.

Remember, with windows quality is important! Install the best you can afford. Energy- efficient windows will make the whole house quieter, save energy, and make it far less drafty.

Window frames come in wood, wood-clad, vinyl or metal. The glazing (glass used) has advanced since the single pane.

Double and triple-glazed, with air or other gases used in between panes, are the recommended norm now.

Low emissivity (Low e) treatments are also recommended. Low e is a reflective shield, an interior tinting, added to south and west facing windows. Low e windows reflect heat, making the home cooler.

Advantages to double glazing and low e are:

  • Improves insulation
  • Reduces heating and air conditioning bills
  • Reduces carbon dioxide emissions into the atmosphere by saving energy
  • Reduces condensation
  • Reduces cold spots and down drafts
  • Makes good use of the sun's heat
  • Durable

There is an energy-performance label on windows from the National Fenestration Rating Council (NFRC). Their rating system for windows rates four factors:

    • U-factor which measures how well a window prevents heat from escaping. Select windows with u—factors of less than 0.47 for all applications.
    • Solar Heat Gain Coefficient (SHGC) is a measure of the solar energy entering the building through the entire window. The lower the number the better.
    • Visible transmittance
    • Air leakage

(This rating is optional for manufacturers)

Sky lights can greatly reduce your need for electrical lighting, saving you money.
Factors considered for windows are also true for skylights.

Solar tubes (8 to 21 inch circular skylights) with a super reflective light shaft, are a relatively new product that channels large amounts of light through a small space with minimal heat gain or loss.

The US EPA Energy Star program covers windows and skylights.

We recommend you visit:

Efficient Windows Collaborative
Energy Star
National Fenestration Rating Council
Green Consumer Guide

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Spotlight on the Experts

Dennis Odin Johnson

Dennis Odin Johnson has been designing, manufacturing and building environmentally green homes and dome homes since 1971. His company, Natural Spaces Domes, is one of the leading manufacturers of geodesic dome homes in the world. During his 37 years of building domes, one of his major focuses has been educating and promoting the green aspect and environmental sustainability of dome homes as well … Read More »

Little Green Steps

To check if your windows are drafty, hold a lighter or candle and go around perimeter of window on a windy day. If the flame flickers a lot or goes out you have drafts! Check all your windows and frames- careful not to catch your drapes on fire!

 Claim a federal and/or state tax credit when installing energy efficient new windows. Check with the Energy Star program and local electricity provider.