Can Window Performance Be Measured for Sound?

Yes.

Two ratings you may encounter are:

• STC
• OITC

They are related, but they emphasize different sound ranges.

What Is STC?

STC stands for:

Sound Transmission Class.

It is widely used to describe resistance to airborne sound and places more emphasis on frequencies such as speech.

What Is OITC?

OITC stands for:

Outdoor-Indoor Transmission Class.

It places more emphasis on lower-frequency exterior sounds such as:

• Traffic
• Aircraft
• Construction

Which Number Is Better?

For both ratings:

Higher generally means greater sound-control performance.

But compare like with like.

Do not compare one product’s STC directly with another product’s OITC.

What Improves Sound Control?

Pella identifies factors including:

• Multiple panes
• Different glass thicknesses
• Air spaces
• Good weatherstripping
• Proper installation

“Triple Pane” Does Not Tell the Entire Acoustic Story.

Envirotech Exteriors can help homeowners evaluate window performance based on the actual problem—traffic, neighbours, aircraft, or general exterior noise.