Window Selector: Find Windows That Fit Your Climate and Noise Level
Five quick steps take you from your ZIP code to three window systems from different brands, each checked against ENERGY STAR for your area, with estimated yearly savings.
The GlassBase Window Selector is a free online tool for US homeowners that turns a ZIP code, window type and size, orientation, shading and outdoor noise level into up to three window systems from different brands, each with estimated U-factor, SHGC, visible transmittance and estimated sound insulation (Rw), a check against the ENERGY STAR Version 7.0 criteria for that ZIP's climate zone, and estimated yearly energy savings compared with a standard double-pane window.
GlassBase does not sell, manufacture or install windows. Performance values are calculated estimates, not NFRC certified ratings.
- 1Location
- 2Window
- 3Orientation
- 4Noise
- 5Results
Location & climate
Enter your ZIP code to look up your ENERGY STAR climate zone.
Window type & size
Pick the product, how it opens, the frame material and the size.
Opening
Frame material
Orientation & shading
Which way does the window face? Is it shaded?
Shading (optional)
Noise & room
Pick the noise outside and the room the window is for.
Outdoor noise level
Room
Window systems for your answers
Questions about choosing windows
What kind of windows should I get for my climate?
ENERGY STAR splits the US into four climate zones, and each sets its own U-factor and SHGC limits. In the Northern zone a low U-factor matters most. The South-Central and Southern zones cap SHGC at 0.23 to limit solar heat. The Window Selector looks up your zone from your ZIP code and checks every system against that zone's limits.
What U-factor and SHGC do I need for my ZIP code?
ENERGY STAR Version 7.0 sets these limits for windows:
| Zone | U-factor | SHGC |
|---|---|---|
| Northern | ≤ 0.22; 0.23–0.24 with SHGC ≥ 0.35; 0.25–0.26 with SHGC ≥ 0.40 | ≥ 0.17; ≥ 0.35 with U 0.23–0.24; ≥ 0.40 with U 0.25–0.26 |
| North-Central | ≤ 0.25 | ≤ 0.40 |
| South-Central | ≤ 0.28 | ≤ 0.23 |
| Southern | ≤ 0.32 | ≤ 0.23 |
Windows must also have air leakage of 0.3 cfm/ft² or less. Your local energy code can differ, so check with your building department.
How do I know if a window meets ENERGY STAR where I live?
Look for the ENERGY STAR label that names your climate zone; it sits next to the NFRC label on the glass. ENERGY STAR's Climate Zone Finder looks zones up by state and county, and its Product Finder lists certified product lines. The Window Selector compares estimated values with the criteria; its check is not a certification.
What sound rating do I need to block traffic noise in a bedroom?
The Window Selector uses Rw, the weighted sound reduction index (ISO 717-1), because that is the value our glass and frame data holds. Your target is the outdoor level you pick minus a quieter indoor level for the room, with the bedroom strictest: 70 dB of busy-street noise in a bedroom needs Rw 40 or more. A window's Rw here is an estimate: the glass unit's value, or the frame's if that is lower. It is not a tested rating for that exact window, and the selector does not convert Rw into other ratings. Ask the manufacturer for the tested value before you buy.
How much will I save per year with new windows?
It depends on your climate, your energy prices and the windows you replace. The selector estimates savings against a standard double-pane window, using hourly typical-year (TMY3) weather from the station nearest your ZIP code and EIA state energy prices. Each result shows the savings per year and over 30 years for all the windows you entered, at today's energy prices: the yearly figure times 30, with no price change assumed.
Should south-facing windows have a high or low SHGC?
It depends on your climate, the direction the window faces, and the balance between heating and cooling. A higher SHGC lets in more of the sun's heat. In winter, that heat lowers your heating bill. In summer, your air conditioner has to remove it. Which effect is larger depends on how much sun reaches the window in each season, how long your heating and cooling seasons are, and how efficient your heating and cooling equipment is. So the SHGC that saves the most can change from one ZIP code and direction to another. The Window Selector estimates both effects for your ZIP code and the direction you choose, assuming a heat pump for heating and an air conditioner for cooling, and ranks windows by their estimated yearly savings.