Business Details
31 Years
experience
Emergency
services
Premium Vinyl Window Replacement in Denver
303 Windows has been a trusted provider of window and door replacement services in the Denver metro area since 1995. Originally established as Centennial Home Improvements, Inc., the company transitioned to specialize exclusively in vinyl window and patio door solutions to meet growing demand for energy-efficient home improvements. Our team combines decades of hands-on experience with partnerships with top manufacturers like Anlin to deliver durable, cost-effective products tailored to Colorados climate. We prioritize clear communication, personalized service, and meticulous installation processes, ensuring every project aligns with our commitment to quality and customer satisfaction.With a focus on energy efficiency, longevity, and aesthetic appeal, we help homeowners enhance their properties value and comfort. Our locally-owned business takes pride in serving Denver and Front Range communities, offering free estimates and lifetime warranties on select products. By maintaining a family-owned ethos, we foster lasting relationships with clients and emphasize transparency, reliability, and community impact in every interaction.
Services
Vinyl Window Installation
Window Replacement
Patio Door Installation
Energy-Efficient Windows
Custom Window Solutions
Details
- Year established: 1995
Highlights and features
- 30 years of specialized expertise in Denvers climate challenges
- ENERGY STAR-certified products for maximum energy efficiency
- Lifetime warranties on select Anlin vinyl windows and doors
- Locally-owned with a focus on community relationships
- Free estimates and transparent pricing with no hidden fees
Associations and certifications
- ENERGY STAR
- National Fenestration Rating Council (NFRC)
- American Architectural Manufacturers Association (AAMA)
What people say
Professional team
Punctual service
High-quality results
Energy-efficient upgrades
Lifetime warranties
Services
Vinyl Window Installation
Our vinyl window installations enhance energy efficiency and curb appeal using Anlin products with Low-E glass and thermal insulation. We handle full-frame replacements, ensuring proper sealing and durability against Colorados weather. The process includes professional measurement, removal of old windows, and precise installation with trim and weatherstripping for long-term performance.
Patio Door Installation
We install energy-efficient vinyl patio doors, including sliding and French doors, designed to improve insulation and aesthetics. Our team ensures proper fitting, tracks, and weatherstripping for smooth operation and security. Upgrades include retractable screens and pet panels, tailored to your homes design and functional needs.
Energy-Efficient Upgrades
Our energy-efficient windows and doors reduce heating and cooling costs with advanced glazing systems and triple-fin weatherstripping. Anlins ENERGY STAR-rated products meet strict efficiency standards, helping homeowners save money while maintaining comfort and reducing environmental impact through superior thermal performance.
Insurance Claim Assistance
We streamline insurance claims for hail, fire, and storm damage, providing documentation and direct communication with providers. Our team replaces damaged windows and doors promptly, ensuring compliance with policy requirements and minimizing out-of-pocket costs for homeowners.
Custom Window Solutions
We offer custom vinyl window designs to match unique architectural styles, including geometric shapes and color options. Our process involves personalized consultations, precise measurements, and collaboration with homeowners to create solutions that enhance natural light, security, and aesthetic appeal for both new and existing homes.
Questions
What types of windows do you install?
We specialize in Anlin vinyl windows, including double-hung, casement, awning, bay, and picture windows designed for energy efficiency.
Do you offer door replacement services?
Yes, we install vinyl patio doors, including sliding, French, and sliding French doors with energy-saving features.
Are your windows energy-efficient?
All Anlin windows we install are ENERGY STAR certified, featuring Low-E glass and thermal insulation to reduce energy costs.
How long do vinyl windows last?
Vinyl windows typically last 20–30 years, with Anlin’s products offering durability against Colorado’s weather extremes.
Do you work with insurance claims?
Yes, we assist with insurance claims for hail, fire, and storm damage, handling documentation and communication with providers.
What areas do you serve?
We serve Denver and surrounding Front Range communities, specializing in local climate-specific installations.
Videos
Reviews (7)
Nancy Dilatush
Dec 22, 2021
Report
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
Report
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. Im 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. Im so pleased that Im 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
Andria White
Aug 23, 2021
Report
I recently had windows installed by 303 Windows I was extremely impressed! I purchased the windows from Jay who answered all my questions he was very knowledgeable, professional with a fun personality! The quality of windows was great. The installers were efficient, polite and neat! I love my new windows Id highly recommend 303 Windows!
Dave Irish
Aug 04, 2021
Report
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. Dont waste your time and money and just go ahead with 303Windows!
David S.
Jul 29, 2021
Report
I highly recommend 303 Windows and owner Jay Lillien. In early 2021, We had Jay and his team at 303 windows replace all windows in our home in Littleton with Amerimax replacement windows (manufactured in Loveland). We are very pleased with the results. We are exceptionally pleased with the professionalism, friendliness, responsiveness and workmanship of the crew, who swapped out all 27 or so windows over two days, and cleaned up all debris. We had a couple minor problems with the windows (a long narrow eyebrow window cracked during a difficult installation, and a few windows had minor manufacturing
Diana Barlow
Jul 08, 2021
Report
WOW - I sincerely want to thank Jay and his crew for a job very well done. Our windows were a particularly difficult size (as in HUGE) and had multiple issues (bowing in the wind for example - as well as WAY too much heat coming through.) There were window replacement companies we interviewed that would not take the job. There were others that did not listen to our concerns. Jay agreed to take on the job, listened to our concerns, and called into the window manufacturer to obtain advice when needed, without speculating when he wasn't sure of the best solution. We REALLY appreciated that kind of
Teri S.
Jun 15, 2021
Report
Positive:Professionalism,Punctuality,Quality,Responsiveness
We got bids from other window replacement companies. Not only did 303Windows have the best price but owner Jays sales approach was low pressure and honest. I prefer working with a small business with a responsive owner. We had all our windows replaced in 2 days by a professional hard-working team. I highly recommend them.
Service:Window installation
We got bids from other window replacement companies. Not only did 303Windows have the best price but owner Jays sales approach was low pressure and honest. I prefer working with a small business with a responsive owner. We had all our windows replaced in 2 days by a professional hard-working team. I highly recommend them.
Service:Window installation
