Energy Upgrade California™ provides up to $4,500 in incentives to single-family homeowners for making select, energy-efficient upgrades with this “whole house” approach.
Before you buy new windows, see if you qualify for the Energy Savings Assistance Program. If you qualify, you may receive windows and other energy-efficient appliances and services for free.
Learning how your home uses energy is the first step to saving. Start saving today by using our Home Energy Survey to understand your energy use.
Keep it clean: If choosing new windows or sash replacements, consider ease of cleaning. Some window sashes allow you to tilt the surface completely so you can easily clean the outside pane.
This chart gives you a good understanding of the basic terminology used when discussing energy-efficient windows. Generally, if you're replacing an existing window, you should at least upgrade to efficient double pane windows and consider features like gas filling and low-e coating. Look for window systems with a combined low U-factor (0.35 or less for California’s climate) and a low solar heat gain coefficient (0.3 or less for California)
| Feature | Description | Rating Range |
|---|---|---|
| U-factor | How well the window prevents heat from escaping. The lower the U-value, the better its insulating characteristics. Consult the ENERGY STAR® website to find the recommended value for your climate. | 0.2-1.2; lower is better |
| Solar heat gain coefficient | How well a window blocks heat from the sun. Lower values signify a window that transmits less solar heat. Consult the ENERGY STAR® website to find the recommended value for your climate. | 0-1; lower is better |
| Visible transmittance | The amount of light permitted through the product. A higher number means more light comes through. | 0-1; higher is better |
| Air leakage | The amount of air movement, in cubic feet, passing through the cracks in the window assembly (cfm/ft). A lower number signifies a tighter window. | Look for 0.01-0.06 |
| Feature | Description | Rating Range |
|---|---|---|
| Multiple glazing (panes) | Window assemblies with more than one pane of glass to help prevent heat loss/gain. Look for double and triple paned windows. | Double or triple pane |
| Gas filling | Multiple glazing assemblies often have a gas filling in the space between panes to boost insulating properties and inhibit heat flow. Argon and Krypton are more efficient than other gasses. | Argon or Krypton |
| Low-emittance coating (low-E) | A microscopically thin, invisible metallic coating, usually on the inside layers of the glass panes. Low-e coatings help prevent heat flow by reflecting invisible, long-wave infrared radiation, thereby lowering the U-factor of the window. | |
| Insulating spacer | An insulating material used as a spacer in the assembly to help prevent condensation. Traditional aluminum spacers aren't ideal. |
| Feature | Description | Rating Range |
|---|---|---|
| Solid steel and aluminum | Least efficient type of frames because they're poor insulators that expand and contract more with weather changes. Choose other types of materials if possible. | $10-$15/square foot |
| Wood | Very good insulator with minimal expansion and contraction, yet require more maintenance and can get moisture damage. Some wood components are treated with preservatives or covered in metal or vinyl to decrease maintenance. | $20-$30/square foot |
| Vinyl | Very good insulator with little maintenance. Can be damaged by the sun and elements, leading to peeling, warping and discoloration. Expands and contracts like metal components with weather changes. Sometimes made with a fiberglass core. | $15-$20/square foot |
| Fiberglass | Very good insulator with minimal expansion. | $20-$30/square foot |
Minnesota Department of Commerce Windows and Doors fact sheet, pp. 2–4
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