What Are Glass Block Windows – Worth it?

Glass block windows are a common fixture in basements and bathrooms. They’re secure, energy efficient, and offer privacy, even without a window treatment.

Glass block windows

While these windows peaked in popularity during the 1980s, they’re making a comeback. You can find them in various designs, patterns, thicknesses, and privacy levels.

If you’re unsure if these windows are right for you, here’s what to consider.

What is a Glass Block Window?

Glass block windows are large panels of smaller thick, glass blocks. The typical glass width is 2″, 3″, or 4″.

While privacy level varies by manufacturer, you’ll often see these three types:

  • Wavy – Wavy is the typical pattern on basement windows, offering maximum privacy.
  • Clear – If you want to see straight through, clear is the design for you. (These don’t offer privacy.)
  • Ice – Windows with an ice treatment appear to have a frosty look.

Aside from privacy levels, you can also find modern glass block windows in numerous designs.

Do Glass Block Windows Open?

Glass block windows can either be fully fixed (meaning they don’t open) or have a small section that extends outwardly for ventilation.

These windows don’t open like a standard window, which is why they’re more energy efficient and secure.

How Much Do Glass Block Windows Cost?

You can find smaller glass block windows inexpensively. For example, a 31″ x 23.25″ glass block window starts at only $100. Depending on size and brand, larger varieties cost as much as $1,000.

The installation cost for a glass block window will be slightly more than standard vinyl windows since the process differs. Installation starts at $60 but can go as high as several hundred, depending on the size and complexity.

What are the Pros and Cons of Glass Block Windows?

Glass block windows are a top option for privacy, but they have a fair share of fallbacks. Here’s what you should know:


  • Inexpensive – Glass block windows are cheaper than most other window types.
  • Offer privacy – These are a good solution if you want to let natural light in your home without giving the neighbors a show.
  • Secure – Since glass block windows are fixed or only have one small ventilation window, they’re safer and hard to break into.
  • Energy efficient – Modern glass block windows are as energy efficient as thermal pane windows and airtight.


  • Heavy – Large glass block windows can be heavy, so you must ensure your wall can support the weight before installation.
  • Low ventilation – Glass block windows have zero to little ventilation, so if you’re someone who wants to feel a breeze, these aren’t for you.
  • Need to be resealed – Over time, the seal around the glass block can wear down, allowing air or moisture to leak.

Glass Block vs. Vinyl Basement Windows: Which is Better?

Picking a window for the basement is no easy feat. You want something secure, energy-efficient, and that fits in your budget. And both options can work.

You can purchase glass block and vinyl windows for about the same price. The benefit of a vinyl sliding window is that it opens for ventilation. The advantage of glass block is a tighter seal, privacy, and added security.

Another factor to consider is aesthetics. Right now, glass block windows are making a comeback, but that comeback could be short-lived. A simple vinyl sliding window will always be in style.

Glass Block vs. Acrylic Block Windows: What’s the Difference?

If you search a home improvement website, you’ll see some windows labeled as glass block and others as acrylic block.

So, what’s the difference?

Acrylic blocks are made of acrylic resin. They feature 2-3 panes of acrylic and are 70% lighter than glass. Some manufacturers claim they are also 33% more energy efficient.

Right now, the most common places you’ll find acrylic glass windows are in bathrooms, as room dividers or shower surrounds. But, you can also find them in exterior window options.

What are the Best Alternatives to Glass Block Windows?

Not sure if glass block is right for you? Or do you want to replace your glass block windows with something new?

These are the best alternatives to glass block windows:

Awning Window

If you want to replace a glass block basement or bathroom window, you can find awning windows in comparable sizes. Awning windows have a hinge at the top and a crank at the bottom that opens them up and outward.

When you shut awning windows, they are among the most secure and airtight.

Horizontal Sliding Window

Another option is the horizontal sliding window. These windows can fit into tight spaces and are operable. You can pick from aluminum, vinyl, fiberglass, and wood-framed sliding windows.

Fixed Vinyl Window

If you love that your current window doesn’t open, replace it with a fixed vinyl window. A fixed vinyl window won’t open either, which provides the security and energy efficiency of glass block.

Acrylic Block Windows

Do you want to keep the look of the glass block but switch it for something lightweight? Go with an acrylic block window. You’ll reap the benefits of a glass block window but gain more energy efficiency.

Where Can You Buy Glass Block Windows?

You can purchase glass block windows at all major home improvement stores, including Lowes, Home Depot, and Menards. You can also find local specialty stores that carry them.

Some top window manufacturers like Pella and Andersen do not carry glass block windows.

How Long Do Glass Block Windows Last?

Glass block windows will last 15-30 years, depending on the manufacturer. But it’s possible for the seal around the window to deteriorate before then and need touching up.

Frequently Asked Questions (FAQ)FAQ

Will glass block windows increase my home’s value?

Glass block windows do not increase a home’s value in a direct way. But replacing an old window with a new glass block window can increase your home’s energy efficiency and security, which adds value.

How do you clean glass block windows?

Clean a glass block window by spraying glass cleaner on it and wiping it clean with a lint-free cloth. Next, go outside to clean the window’s exterior. If it has stuck-on dirt, start by hosing it off. Then, clean it with your glass cleaner and cloth.

Are there glass block egress windows for the basement?

While not common, you can find glass block egress windows. These windows are large enough for emergency exits and are on a hinge so that they easily open.

Are glass block windows waterproof?

A properly installed, well-maintained glass block window is waterproof. These windows are an excellent option if you live in a flood zone.

Why are glass block windows popular for the basement?

A glass block window prevents passersby from seeing inside while letting natural light into the basement. These windows are also waterproof and secure, making them a good choice.

Final Thoughts

Glass block windows make great additions to the basement and bathroom. You can find them in many unique sizes, offering privacy without blocking natural light. They are secure, waterproof, and energy efficient.

The most significant disadvantage to glass block windows is that they don’t open or open very little. And, some people just don’t like the look. The best alternatives to these windows include awning, horizontal sliding, fixed vinyl, and acrylic block windows.