Glass and Glazing Efficiency: What You Need to Know

10/09/2020

How do you achieve optimal efficiency in windows? This seemingly simple question has a much more complicated answer. Glass Magazine’s April 2020 Issue (page 48) discusses this topic at length.
Below are some key takeaways.

How to Determine Performance

Know the Numbers

When choosing windows, glass is an important factor, however, the windows’ glazing and frame combination is arguably more important when it comes to performance.

In order to determine efficiency values, you need to look at the window as a whole, not just the glass. Choosing the right window glazing is important, but it needs to match the frame capabilities to ensure the performance metric. If only the glass meets the performance goals, the windows may, or may not, meet the required specification.

Consider the Application

It’s also important to consider the application of your windows. Storefront and curtain walls perform differently – they need to meet different structural, water, and air performance requirements. When choosing efficient windows, consider thermal performance targets. Typically, curtain walls afford more options than storefronts do – this is a consideration to be made when choosing materials.

Keep Design in Mind

One challenge when choosing materials is when the desired efficiency is at odds with the design of the building. Glass Magazine highlights how this struggle often plays out:

In recent years, this has been the case with trends toward ultra-clear, less reflective glasses that can create challenges with solar heat and glare. “This is a big hurdle when it comes to glass performance,” says Viracon’s Schmidt. “It’s important to work with glass suppliers to find a compromise.”

When such conflicts arrive, the designer and builder need to determine how much each is willing to give on appearance/performance to find an ideal solution.

Additional Considerations

Connection Points

Once you’ve selected your materials, how the building comes together is critical when it comes to efficiency and thermal performance. Performance needs to carry over into each of the connection points as well. Glass Magazine suggests that project teams model the interfaces to avoid any problems.

The Building as a Whole

When it comes to performance, it must carry throughout the entire building to have any real impact. Additionally, the window coverings inside the building can impact performance overall. Will the building be using sunshades or blinds? These questions are important to consider during the build phase as well.

Occupant Education

Finally, it’s important that occupants of the building understand how best to use their windows to achieve efficiency and optimal thermal performance. This can be further mitigated with automated systems for HVAC, shading, and lighting. For best results, building managers and occupants should understand how the automated systems work and their settings.

Achieving optimal efficiency requires consideration of a variety of factors.
Not sure which is right for your project? Call to discuss options or contact us for a quote.