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Two names.
One company.
Built from the ground up.

In 2009, the Schwartz brothers and the ATI group acquired ABC Window Co., a Southern California manufacturer with roots dating back to 1971. Bringing the two names under one roof strengthened a business philosophy that was already clear: manufacture with care, deliver with consistency, and stand behind the work long after it leaves the floor.

We make the window.
We sell the window.
We stand behind it.

With five manufacturing facilities, our own installation crews, and dedicated service teams, ATI Windows/ABC Window Systems manages the process from production to jobsite with hands-on control from start to finish.

No distributor in the middle means a clearer process, more direct value, and fewer layers between the people who make the product and the people who use it.

For builders, contractors, and homeowners, the result is straightforward: competitive pricing, dependable lead times, and consistent quality for projects of every size.

Founders

They run it like
their name is
on every window.

Stephen Schwartz, CEO, and Daniel Schwartz, Chairman

Stephen Schwartz

CEO

Stephen Schwartz brings decades of building industry experience to ATI Windows/ABC Window Systems as a general contractor, developer, and building products manufacturer.

As CEO, Stephen leads a business built on fundamentals — manufacturing well, serving customers directly, and delivering on schedule. When not at the office, you’ll find him travelling with his family.

Daniel Schwartz

Chairman

Daniel Schwartz brings 40 years experience in the building industry across homebuilding, manufacturing, product development, and business growth. His financial perspective guides ATI Windows/ABC Window Systems with discipline, long-term thinking, and a clear view of where the industry is headed.

As Chairman, Daniel works with the products, processes, and ideas that strengthen the company for builders, contractors, and homeowners. Outside of work, he enjoys spending time with his grandchildren.

Milestones

Where we’ve built, and when.

1971

ABC Window Co. is founded

“Whitey” Hegwer opens ABC Window Co. in Ontario, California, building aluminum windows for the Southern California market.

1992

The Schwartz brothers start Aluminum Technology Inc.

Stephen and Daniel Schwartz found Aluminum Technology Inc. to manufacture aluminum windows.

1998

Vinyl joins the line — and a new name

Aluminum Technology Inc. begins manufacturing vinyl windows alongside aluminum, and changes its name to ATI Windows.

2000

ATI expands into Nevada — Las Vegas

ATI opens in Las Vegas, bringing in-house manufacturing and its own crews to a fast-growing market.

2009

ATI acquires ABC

During the Great Recession, ATI buys ABC’s manufacturing assets — uniting the two companies under one roof.

2018

Expansion to Arizona — Phoenix

A Phoenix facility brings local manufacturing and service to Arizona builders, putting our product closer to where it’s installed.

2020

Ennion formed to make aluminum doors

Ennion and Ennion.com are formed to produce and sell our thermal-break aluminum doors and windows and specialty glass products.

2025

North to Fairfield, Northern California

Our newest location extends coverage up the state, with the same products and the same standards builders have counted on for decades.

How we work

It's a simple philosophy. Build it right. Sell it direct. Stand behind it.

No middleman

We manufacture what we sell. No distributors, no extra markups — just direct-from-manufacturer value and a single point of accountability.

Our own crews

Installation and service teams across California, Nevada, and Arizona mean the people who stand behind the work are the people who do it.

American-made, built to last

Energy-efficient windows and doors, made here at home and backed by more than fifty years of doing this the right way.

Start a project. Talk to a person.

Sales sales@atiwindows.com
Main (909) 946-3697
Hours Mon – Fri · 7:00 AM – 3:30 PM