Business Details
31 Years
experience
Emergency
services
Your Trusted Denver Window Replacement Experts
303 Windows has been a trusted name in window replacement and installation services since 1995. As a family-owned business based in Denver, Colorado, we specialize in providing high-quality vinyl windows and doors tailored to meet the unique demands of Colorado's climate. Our commitment to excellence is reflected in our use of top-tier products from brands like Anlin, ensuring durability, energy efficiency, and aesthetic appeal. With over 30 years of experience, we have built a reputation for delivering professional installations, personalized service, and long-lasting solutions that enhance homeowners' comfort and property value. Our team prioritizes clear communication, transparency, and customer satisfaction, offering free estimates and standing by our work with confidence.We understand the importance of trust in home improvement projects, which is why we treat every client and their home with the respect and care we would extend to our own family. Our expertise in navigating insurance claims for window damage further demonstrates our dedication to making the process stress-free for our clients. By focusing on innovation and staying ahead of industry trends, we ensure our customers receive cutting-edge solutions that combine functionality with modern design. Our local presence and deep community ties reinforce our commitment to serving Denver and the Front Range with integrity and pride.
Services
Vinyl Window Installation
Window Replacement
Patio Door Installation
French Door Replacement
Energy-Efficient Windows
Custom Window Solutions
Insurance Claim Assistance
Window Repair
Door Replacement
Free Estimates
Details
- Year established: 1995
Highlights and features
- We have over 30 years of experience in window replacement tailored to Colorado's climate.
- Our team provides expert installation with attention to detail and energy efficiency.
- We offer free estimates and transparent pricing with no hidden fees.
- Our locally-owned business understands the unique needs of Denver homeowners.
- We stand by our work with a lifetime warranty on Anlin products.
What people say
Professionalism, Punctuality, Quality
Outstanding customer service
Energy-efficient results
Expert installation team
Competitive pricing
Services
Vinyl Window Installation
Our vinyl window installation service delivers durable, energy-efficient solutions designed to withstand Colorado's climate. Using premium Anlin products, we ensure precise fitting and professional installation that enhances home insulation, reduces energy costs, and improves curb appeal. Each project includes removal of old windows, proper disposal, and meticulous attention to detail for seamless integration with your home's architecture.
Window Replacement
We specialize in replacing outdated or damaged windows with modern, high-performance vinyl options. Our process includes a comprehensive consultation, custom measurements, and installation of windows that improve thermal efficiency, noise reduction, and security. We handle everything from single replacements to full-home upgrades with minimal disruption to your daily life.
Patio Door Installation
Upgrade your home with energy-efficient vinyl patio doors that combine style and functionality. We install sliding and French doors with features like Low-E glass and weatherstripping to maximize energy savings. Our team ensures proper fitting and finishing touches, including trim and sealing, for a polished, secure installation.
Energy-Efficient Windows
Our energy-efficient windows feature advanced glazing, insulated frames, and weatherstripping to minimize heat transfer. Designed to meet ENERGY STAR standards, these windows reduce utility bills while maintaining indoor comfort. We help homeowners select options that align with their aesthetic preferences and sustainability goals.
Insurance Claim Assistance
We simplify the insurance claims process for window damage caused by hail, fire, or theft. Our team works directly with your insurer to document losses, provide detailed estimates, and ensure timely approvals. This service alleviates stress, allowing you to focus on restoring your home with confidence.
People
Jay Lillien
Owner
Jay Lillien founded 303 Windows in 1995 and has led the company's transition to specialize in window replacement. With decades of industry experience, he prioritizes customer satisfaction, transparent communication, and quality craftsmanship. Jay's hands-on approach ensures every project meets the company's high standards.
Questions
What types of windows do you install?
We install vinyl replacement windows including double-hung, casement, awning, bay, and picture windows from Anlin.
Do you offer energy-efficient options?
Yes, all our vinyl windows feature energy-saving technology like Low-E glass and insulated frames to reduce utility bills.
How long does window replacement take?
Most full-home replacements are completed in 1-2 days, depending on project scope and weather conditions.
Do you work with insurance companies?
Yes, we assist with insurance claims for storm, hail, and accidental window damage to streamline the process for homeowners.
What areas do you serve?
We serve Denver and surrounding Front Range communities in Colorado.
Do you offer warranties?
Yes, we provide a lifetime warranty on Anlin windows and stand behind our installation workmanship.
Videos
Reviews (6)
Blaise Singer
Jun 25, 2022
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Wow! I am so impressed! I love my new windows! Jay is honest, responsive and professional. He is very knowledgeable and has great ideas. Jay and his installers, Rich and Mike, were very respectful to me and my home. They did what they said they would do. The install was fast and they kept my home clean during the process. I was very nervous and hesitant about the whole process, but I'm so glad I used 303 Windows. I couldn't be happier!
A. W.
Mar 16, 2022
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We worked with Jay replacing over 40 outdated Viking windows in our house with Amerimax Craftsman windows, advice and insights he provided were very helpful. He gave us a number of references which all commented very positively on their related projects. The at times difficult measurement and install was looked after by John and his team of professional and courteous installers and worked out very well. Follow-up work on our end after the install was completed was minimal. Jay followed up on manufacturing issues when the manufacturer was simply not responsive and also addressed incorrectly delivered window panes and exterior caulking issues, the latter representing the main challenge we had so far.
Unfortunately Jay does not seem to be available/interested in smaller projects, we are planning to install three new windows in locations that don't have windows today, despite contacting 303 windows multiple times we never heard back.
Unfortunately Jay does not seem to be available/interested in smaller projects, we are planning to install three new windows in locations that don't have windows today, despite contacting 303 windows multiple times we never heard back.
Jay J.
Jan 12, 2022
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My experience with Jay, the owner, was fantastic from the minute I talked to him on the phone. He was on time, professional and listened to want we wanted to do with our windows. He had several windows and took the time to explain the differences between the windows. No pressure. It was an easy choice to have Jay install the new windows. When the windows arrived, he called and set up a time for installation.
His crew was very professional, answered my questions and took the time to make sure the work area was spotless before they left. The new windows look fantastic! If you need new windows, don't waste your time calling anyone else.
His crew was very professional, answered my questions and took the time to make sure the work area was spotless before they left. The new windows look fantastic! If you need new windows, don't waste your time calling anyone else.
Nancy Dilatush
Dec 22, 2021
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I would highly recommend 303 Windows because of service, price and Jay's vision. When I asked for a quote, it was for 4 bedroom windows, very straight forward. Jay saw the large picture window and sliding glass door in my living room and he made a suggestion. Needless to say, I took his advice and the large picture window looks better than I imagined it could. I'm very happy with the windows, the installation (installer was great) and Jay's vision!
Donna Lefferdo
Oct 28, 2021
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I used 303 Windows to replace some of my old inefficient windows in my house and install their white vinyl windows. Jay Lillien came out to do an estimate. I'm amazed at how affordable these windows are compared to other companies. He was very helpful and knowledgeable of the style to fit my house and design. The installation team was very professional and did a beautiful job. I'm so pleased that I'm having them finish the rest of the windows in the house! These windows are so energy efficient and attractive. I love my new kitchen view, family room view and the rain glass in the bathroom.
Dave Irish
Aug 25, 2021
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Last year I had 20 windows and a patio door replaced by 303Windows. Jay was great in arranging everything and his experienced crew did it in one day leaving no trace behind but fantastic new windows. I waited to review them until I had a whole year of use. My Xcel bills are way down, the home is much more comfortable, and the noise reduction was dramatic. The price was a fraction of the large corporate window replacement companies that you see adds for every 30 seconds. Don't waste your time and money and just go ahead with 303Windows!
