What is Low-E Glass, and How Does It Make Windows Energy Efficient?

While many windows may look the same to the naked eye, not all window glass is created equally. Homes with windows installed prior to 1990 likely don’t have Low-E glass, making them less energy efficient and due for replacement. But what exactly is Low-E glass, and why has it become a highly sought feature in most modern windows?

Low-E Glass vs. Regular Glass

Low-E glass, also known as low-emissivity glass, contains a microscopic coating that reflects heat and UV light. While regular glass allows heat and cold to permeate, resulting in hot rooms in the summer and cold rooms in the winter, Low-E glass reflects heat away from the home in the summer and helps keep heat inside in the winter.  

The nearly invisible insulative coating on Low-E glass helps reduce the load on heating and cooling systems and offers significant energy savings.

In addition, Low-E glass provides better protection against fading for household items like artwork, furniture, and flooring by reducing the amount of UV light that passes through it.

Unlike tinted glass, Low-E coatings do not make the room darker and allow natural light to pass through.

Benefits of Low-E Glass:

• Increased home comfort
• Lower energy bills
• UV protection and glare reduction
• Durable and long-lasting
• Allows natural light to pass through
• Increased home value

Feature	Low-E Glass	Regular Glass
Comfort	More consistent room temperatures	Fluctuating temperatures and drafts
Energy Efficiency	High: Reflects heat leading to lower energy costs	Low: Heat passes through freely, causing systems to work harder
UV Protection	High: Blocks most UV rays helping protect furniture and floors from fading	Low: Allows significant UV transmission
Cost	Higher cost: offset by long-term savings and increased home value	Lower cost: less energy efficient with no notable increase in resale value

Types of Low-E Glass

There are two types of Low-E glass coatings: hard-coat (pyrolytic) and soft-coat (sputtered)

1. Hard-coat Low-E glass: Also known as pyrolytic Low-E glass, hard-coat Low-E glass is produced by baking the coating onto the glass at high temperatures. This process makes the coating extremely durable.
2. Soft-coat Low-E glass: Also known as sputtered Lowe-E glass, soft-coat Lowe-E glass is applied in multiple thin layers. This process makes the coating more delicate but offers better heat protection.

Climate is the largest determinant when it comes to choosing between the two. Hard-coat Low-E glass is generally better in harsher or colder climates, with soft-coat Low-E glass offering better energy efficiency in warmer climates.

A window replacement expert, like the ones at Energy Exteriors NW, can help you determine which coating type best suits your needs.

Is Low-E Glass Worth It?

Yes. While initially higher cost, investing in Low-E glass windows offers long-term savings through lower energy bills, reduced fading of household items, and increased resale value.

You’ll enjoy added comfort in your home without restricting natural light.

If you’re ready to improve both the performance and appearance of the windows in your home, contact Energy Exteriors NW.