Cold Glass and Comfort: Why You Feel Cold Near Old Windows

Your thermostat says 70°F, but you're uncomfortable near the windows. According to ASHRAE research, you're not imagining it—poor-performing windows create real comfort problems beyond just air leaks.

Radiant Heat Loss

According to the Lawrence Berkeley National Laboratory, your body constantly radiates infrared heat—that's how thermal cameras see you. When you're near a cold surface (like a cold window), your body radiates heat toward that surface faster than normal.

This radiant heat loss makes you feel cold even when the air temperature is comfortable.

Interior Glass Temperatures

According to LBNL testing, interior glass surface temperatures vary dramatically:

| Window Type | Exterior: 20°F | Interior Glass Temp |
|-------------|----------------|---------------------|
| Single-pane | → | 32°F |
| Old double-pane | → | 42°F |
| Low-E double | → | 54°F |
| Triple-pane | → | 62°F |

The difference between 32°F glass and 62°F glass is the difference between feeling cold and feeling comfortable.

The "Cold 70" Effect

According to ASHRAE comfort research, most people feel comfortable at 70°F with normal interior surfaces. But if walls, floors, or windows are significantly colder, you need higher air temperature to compensate—sometimes 75°F or more.

This means old windows force you to heat your home to higher temperatures for the same comfort.

Beyond Energy Bills

According to the U.S. Department of Energy, discomfort from cold windows causes:

• Avoiding certain rooms in winter
• Cranking thermostats higher
• Using space heaters (expensive and potentially dangerous)
• Rearranging furniture away from windows

The Modern Window Difference

According to LBNL, high-performance windows eliminate cold glass:

• Interior surface stays within 5-10°F of room temperature
• You can sit comfortably next to the window
• No radiant heat loss pulling warmth from your body
• Thermostat setting can be lower while feeling warmer

The Bottom Line

If you avoid sitting near windows in winter, that's a sign your windows are significantly affecting your comfort. Modern windows solve this problem—making your entire room usable year-round.

*For all replacement signs, see: [Signs Your Windows Need Replacing](/guides/signs-windows-need-replacing)*