If your energy bills are rising and your rooms feel drafty, your windows could be the culprit. Many homes and businesses in Washington DC still use outdated, inefficient glass that leaks heat in winter and traps it in summer.

In this post, we’ll show you how to recognize energy-efficient window glass, what to look for when upgrading, and why it matters in the DMV climate.

 Signs Your Glass Isn’t Energy Efficient

Here are common signs that your window glass may need an upgrade:

• Drafts near windows even when they’re closed

• High heating or cooling costs

• Condensation between panes (for double-pane windows)

•  Poor noise insulation from outside

• Cold glass surface in winter / hot in summer

If you’re experiencing any of these, your windows are likely not energy efficient.

 What Makes a Window Energy Efficient?

Not all windows are created equal. Here’s what makes a difference in energy performance:

• Double or Triple Pane Glass: Multiple panes with insulating gas reduce heat transfer.

• Low-E Coating: A thin, invisible layer that reflects heat while allowing natural light.

• Argon or Krypton Gas Fills: These gases insulate better than air between panes.

• Thermally Broken Frames: Especially important in metal frames to prevent heat loss.

Look for the ENERGY STAR® label when selecting replacement windows in the DC area.