Diamond glass block vented

Glass Block Windows

Most people don’t know that glass block windows have been in use for over a century. They first gained popularity during the Great Depression due to their inexpensive nature. Although glass block windows have the impression that they are antiques, many offices, houses, and other structures still use them today. They have seen a serious revival of popularity in the last couple years.

Many people install glass block windows for their aesthetic appeal. However, there are many benefits to choosing this type of windows over others. They are a great option for basement windows, as they are very resistant to break-ins and weather. They are also commonly used at the front of a house or on bathroom windows to let light in without sacrificing privacy. Finally, they can be used as an interior non-load bearing wall along foyers or in bathrooms. Their unique design feature can upgrade the style and functionality of many interior spaces. In fact, many people ask if they can still find glass block windows near me in many cities. 

Diamond glass block vented

How are Glass Blocks Made?

Glass blocks are sometimes called glass bricks. They are made by fusing two sections of glass into a single block with a hollow center. They are usually between 2” to 3” in depth, but can sometimes be deeper. They then get installed like building blocks. They do let light through, but do not have the same clarity as regular glass windows. 

The majority of glass blocks are found in square shapes, but they can be made into other shapes like hexagons. They can also be curved and used as end blocks depending on the design. Modern glass block windows are available in a wide variety of colors, patterns, textures, degrees of transparency, and sizes. Some of the most popular patterns are wavy, diamond, clarity, and ice. The wide array of options allows glass block windows to be customized to meet any project’s needs.

Installation Options

Glass block windows are usually installed in one of three different ways. The first and least expensive option is to simply stack the bricks on top of and next to each other with nothing in between. The second most popular way to install them is stacked with a layer of mortar and sand between them. This option provides a lot of security. However, the mortar could potentially crumble if the foundation settles. The most expensive, but also the most energy efficient option is to install them with vinyl spacers. This installation is 20% more energy efficient and more waterproof than the other installations. If you are in an area that deals with flooding, glass block windows installed with vinyl spacers could be a great investment.

If ventilation is a problem in your bathroom or basement, there are glass block window options with a vent installed in the middle. Like the blocks themselves, the vent is also airtight and secure. A set of windows with a center operable vent is just as secure and strong as one without, while still allowing for some air flow and ventilation.

Where to Install Glass Block Windows

  • Basements
  • Bathrooms
  • Room dividers
  • Skylights
  • Doorways

Benefits of Glass Block Windows

Glass block windows with vent

There are many different reasons a homeowner or landlord might choose to install glass block windows in their property.

Energy Efficiency

Most standard glass block window options are about as efficient as thermal-pane windows and twice as efficient as single-pane windows. Some modern glass block windows even meet Energy Star standards. In addition, some options are low-E, so they reduce the amount of heat lost through the glass. Installing the windows with mortar between the blocks eliminates much of the risk for air leakage. This also has the added benefit of enhancing heat control and minimizing noise and dust. This can help significantly lower your utility costs every month. The hollow centers of the windows’ design help them generate thermal insulation values similar to double-pane windows.

In addition, glass blocks also have the advantage of being highly sustainable. It is recyclable and can be produced from recycled materials. 


The various patterns, textures, and transparency options make these windows great for privacy. You can allow the majority of light into your space without sacrificing privacy. This makes these windows especially appealing for bathrooms and basements. Thanks to this design, you don’t have to worry about window treatments or other ways to block your view. They can also be installed in places where valuables are stored, like your basement, without showing off what is being stored there. They are also common in bathrooms to allow natural light in without compromising privacy. Glass blocks do not require you to choose between light or privacy, like a standard window with blinds or curtains would.



Many homeowners worry about their windows because of their security. The density and construction of modern glass block windows make them great for security. Due to their thickness, they are next to impossible to break through, unlike most other residential or commercial windows. In addition, even if someone were to break one of the blocks, that wouldn’t be nearly enough space to fit through.

Enhanced Curb Appeal

Glass block windows feature distinct patterns and designs, which are foolproof ways to boost your home’s aesthetic appeal. If you want to breathe new life into a seemingly dull room, these windows are the way to go. They can make a home appear more upscale. Installing glass block windows can make a wall or window appear more dramatic and well-designed.

Reduced Maintenance

Glass block windows are specifically designed to be stationary and installed directly in your walls. This means you won’t have to apply special coatings or any other window treatments seasonally just to make sure they keep your interior comfortable.

Greater Comfort

Energy efficient glass block windows can help improve and regulate the comfort of your space. They work to keep the interior temperature consistent throughout the year. With the addition of low-E glass, they can reflect heat away from your interior during summer while preventing heat from escaping during winter. Since they are also airtight, you won’t have to worry about air leaks and drafts.

How to Incorporate Glass Block Windows

glass block windows with vent installed

Many glass blocks in the 1980s had a cloudy effect on the glass. Modern glass block windows are available in many more styles. You should stay away from the cloudy pattern, otherwise you run the risk of the design looking outdated. 

In the past, entire walls could be constructed out of glass blocks. This can also look outdated. Installing them in smaller chunks gives a much more modern feel.

Remember that glass blocks give off a warm back lit glow. They should be surrounded with warm, matte surfaces instead of glossy ones.

Glass Block Windows Near Me

How do I find  glass block windows near me? Look no further than American Thermal Window. American Thermal Window has been a leader for Chicago window products for over 35 years. We are Chicago’s top-rated window and door company and serve all of Chicagoland. Our experienced and knowledgeable staff can assist you in your search for the right replacement windows. Whether you know exactly what you want or have not even started the search, we are here to help! We have multiple vendors, allowing us to find the perfect price and design for you.