Glass Block Windows: Pros, Cons, Cost, and More

Your home may be your castle, but adding glass block windows can make it look like one. Glass block windows aren’t just attractive; they’re also highly energy-efficient and offer great security. But, they’re not always the best choice in every room or budget. They’re expensive (both in terms of material and installation) and offer no ventilation. Yet, depending on your design preferences and placement, those cons may not outweigh the benefits.

Let’s examine the pros and cons of glass block windows to help you decide if they’re a clear winner for your next project.

What Are Glass Block Windows?

Glass block windows can usually be found in basements and bathrooms, but they can be installed pretty much anywhere. Instead of traditional windows, which are usually made of a single pane of transparent glass, glass block windows are made of multiple blocks of thick glass inset into a window frame. These thick glass blocks let light flood into the room without allowing anyone to see through them completely. So you get tons of both natural light and privacy.

Pros of Glass Block Windows

Glass block windows have a whole lot going for them, especially if you choose to install them in your basement, bathroom, or ground-floor windows.

Energy Efficiency

Glass block windows provide greater energy efficiency, with some factory-built glass block windows meeting federal ENERGY STAR® efficiency guidelines. To identify these highly efficient windows, just look for the ENERGY STAR® designation on the glass. 

Most standard glass block windows are about as efficient as thermal-pane windows, twice as efficient as single-pane, and are airtight. Some glass block windows also have low-E glass properties, meaning they are able to reduce the amount of heat lost through the window.

In addition, glass block windows are also noted for their remarkable ability to let light into even the darkest of spaces, saving on the energy costs associated with lighting basements and other dark areas.

You can also vent your glass block windows to allow for airflow, further increasing energy efficiency by reducing cooling costs.

Weather Resistance

Another benefit of a glass block window’s tight seal is that it’s also nearly 100% waterproof. This makes them a popular choice for basement egress windows or other areas at risk of flooding.

Keep in mind, though, that if your basement window is in a bedroom, your window must be able to open for exit. If that’s the case, opt for double-pane instead of glass blocks.

Aesthetic Appeal

Glass blocks aren't just great for exterior windows. They can also offer a dramatic, upscale look for shower doors, wet bars, garage windows, partition walls, and large exterior windows. You can choose from several designs, patterns, colors, and even customized etchings.

The most common glass block projects, though, are more practical in application, like basements and bathrooms. Installing glass block for exterior windows can greatly enhance the curb appeal of your home, offering a unique alternative to traditional glass panes.

Security

Glass block windows are especially useful for basements and first-floor windows because they are very hard to breach. They’re made of masonry, and that means they’re nearly impossible to remove. 

Privacy

Glass block windows let in light, but not prying eyes—making them a solid choice for areas like the bathroom, entryway, or closet. Even if someone stands directly next to glass block windows, they can only see the shape of a person or thing, rather than a clear picture like a traditional window.

Cons of Glass Block Windows

Installing glass block windows can enhance the privacy, style, and energy efficiency of any room. But while there are numerous benefits to glass block windows, there are also a few cons.

Cost

The cost of glass block windows is often slightly higher than that of traditional glass panes. You’ll pay anywhere from $500 to $1,000, including professional installation. Costs will vary, though, depending on the size of the job and your location.

Limited Ventilation

While some glass block windows offer small vents, it’s nothing compared to the ventilation of a traditional glass window. Part of the appeal of glass block is its waterproofing and tight seal, which means ventilation is extremely limited (if not completely nonexistent). 

If you’re installing glass block windows in a bathroom with high humidity, like your bathroom, make sure you install a fan to remove humidity since you can’t rely on a window. 

Heavy

Glass block is quite a bit heavier than a regular window, especially the more you need. For installation, you’ll need to add extra support to ensure a tight and safe fit. The size and shape make it harder to install glass block windows, but certainly not impossible. Just make sure you work with a professional who understands the materials’ unique needs. 

Maintenance

To keep enjoying the energy-saving benefits of glass block windows, there are some steps you need to take to maintain your windows. You’ll need to have your glass blocks resealed every few years, something that is generally not necessary for solid glass pane windows.

Complex Installation

To reap the rewards of glass block windows, it’s best to find a glass block installation company. That’s because glass block window installation can be trickier than with solid pane windows. In general, it’s better to have a pro preassemble the window and fit it into a pre-cut frame than to try to build up the window into the frame block by block.

So if you’re looking to install the window yourself—and especially if you’re trying to make a curved glass block wall—the unique challenges of glass block will definitely be a con for you.

Are Glass Block Windows Right for Your Home?

If you’re looking for an aesthetically appealing, highly secure, and energy-efficient window option, then glass block could be just the ticket. But if your preference is a low-maintenance, easy-to-install, and budget-friendly window, then a glass block window may not be the thing for you. Consider the pros and cons of glass block windows in comparison to your needs and wants to decide what’s right for your budget and home.