Diligent Window Supply


Diligent Window Supply offers single-source supply and installation for residential and commercial contractors across the Baltimore area. Open Monday – Friday (7:00am – 4:00pm).

Contact Us
Contact Us


About Diligent Window Supply

Welcome to Our Wholesale Windows & Doors Company in Baltimore, Maryland. At Diligent Window Supply, we take pride in being the go-to wholesale supplier of windows and doors for both residential and commercial contractors in the vibrant city of Baltimore, Maryland. With years of experience under our belt, we have honed our expertise to deliver top-notch products and services that cater to the unique needs of our clients.

Baltimore is a city rich in history and character, with diverse neighborhoods and districts that each tell their own unique story. We understand the importance of preserving the architectural heritage of this city, and that’s why we specialize in providing Historic Windows that perfectly complement the distinct charm of Baltimore’s various districts. Whether it’s a historic rowhouse in Fell’s Point or an elegant building in Mount Vernon, our windows seamlessly blend modern functionality with timeless aesthetics.


Available Products

Experience an array of window and door sizes, proudly presented by Diligent Window Supply in partnership with Slocomb Windows & Doors. View Products

With the steadfast support of Diligent Window Supply, our reputation and core business have flourished, now spanning eight surrounding states. View Products

For more than five decades, Trimline has been a stalwart provider of top-tier custom windows. View Products

Guardian, in partnership with Diligent Window Supply, stands as a premier manufacturer of top-tier entry and security door products. View Products

Why Diligent Window Supply is Your Ideal Partner

Choosing Diligent Window Supply means gaining more than just access to top-quality windows and doors. It entails forging a collaborative partnership with a team deeply committed to exceeding your expectations. Here’s what distinguishes us:

Whether you’re a seasoned contractor seeking premium window and door solutions or an aficionado of historical preservation aiming to safeguard the architectural heritage of your Baltimore property, Diligent Window Supply is here to fulfill your needs.

Our dedicated team of professionals upholds the highest standards of professionalism at every turn. From initial consultation through to final installation, expect transparent communication, meticulous attention to detail, and a seamless, stress-free experience.

We shoulder the responsibility of being your wholesale supplier with the utmost seriousness. Our products are meticulously curated to meet uncompromising standards of quality and longevity. With Diligent Window Supply, durability is never in question.

Exceptional service forms the cornerstone of our philosophy. Our customer-centric approach ensures that your unique needs and preferences take center stage. We’re here to transform your vision into reality.

By choosing Diligent Window Supply, you’re embracing a commitment to elevating quality benchmarks. Our unwavering dedication to premium materials and skilled craftsmanship guarantees that every product we deliver is a masterpiece in its own right.

Clear Insights

Window Products

Innovative Window Technologies for Smart Homes

In the era of smart homes, windows have evolved beyond simple panes of glass to become integral components of intelligent living spaces. At Diligent Window ...
Read More →
Window Products

Understanding Window Ratings: What Do Energy Star and NFRC Labels Mean?

When it comes to choosing the right windows for your home, understanding window ratings is crucial. Among the most significant ratings you’ll encounter are the ...
Read More →
Window Products

Top 5 Signs It’s Time to Replace Your Windows

Windows are essential for your home's comfort and energy efficiency. They allow natural light to flood your space, provide ventilation, and offer beautiful views of ...
Read More →