Replacement Windows — Window Design Group





Serving Thousand Oaks · Westlake Village · Burbank · Santa Clarita · Simi Valley · LA & Ventura Counties
☎ (800) 577-0643
Milgard Authorized Dealer · AMI Premium

Decades of installing Milgard in Southern California.

Vinyl, wood and aluminum-clad replacement windows from Milgard and AMI. Tuscany Series, Style Line, Trinsic, Aluminum, Ultra fiberglass. Three generations of family install crews — factory-trained, never subcontracted. Two-window minimum on every job.

Replacement Windows installation
A Tuscany Series install in Westlake Village — Milgard's most-installed premium vinyl, insulated E-glass.
Premium brands we hand-pick and install
MilgardAMI

Order your windows and window coverings today.
40% off premium · $0 DOWN · 0% interest for up to 84 months · through EnerBank

What We Install

Replacement Windows, in every configuration we trust to last.

Milgard Tuscany Series

Premium Vinyl Replacement

Our most-installed Milgard line. Energy-efficient insulated glass, durable extruded vinyl frames, the Tuscany you have seen across Conejo Valley. Backed by Milgard Full Lifetime Warranty for original homeowners — parts AND labor.

Milgard Style Line · Trinsic

Contemporary & Architectural

Style Line for clean modern profiles; Trinsic for architectural builds with unobstructed views and slim sightlines. Factory-finished colors, no painting, no upkeep.

Milgard Ultra · Aluminum

Fiberglass & Aluminum-Clad

Ultra Series fiberglass for extreme durability and energy performance. Aluminum lines for narrower frame profiles. Both for homeowners who want the strongest possible long-term ROI.

AMI Premium

American Made Windows

AMI replacement windows engineered for SoCal climate — double-pane insulated E-glass with substantially better energy performance than single-pane originals. Real impact on cooling bills.

How We Work

Three steps. Same family team. Every install our name on it.

01

Free In-Home Consultation

A family team member visits, measures every opening, walks through options. No high-pressure sales. About an hour.

02

Hand-Picked Order & Build

We order direct from our manufacturers (no middlemen) and our family workshop preps the install. 2-5 weeks depending on product.

03

Family Crew Install

Our in-house crew installs every product. We clean up. We come back 6 months later to check.

Real Google Reviews

★★★★★  5.0 from 11 verified Google reviews.

Recent customer stories from our installs across Southern California — names, dates, and words preserved exactly as posted.

S
Sheena M
Mar 2026 · Google
★★★★★
"Had 32 windows replaced, 32 shutters added, a new front door, a new French door, and blew out our back wall and added a 24 foot stacking door with electric shades. It's beautiful, the process was seamless, and I'm a happy customer."
C
Cinthya Perez
Apr 2026 · Google
★★★★★
"I could not recommend them more. They were professional and did quality work. And they made sure that commitments were kept."
A
Avery Hatch
Apr 2026 · Google
★★★★★
"I am so happy with the outcome of the windows installation. Beautiful work. Talented crew and a reasonable price"
E
el simmonons
Apr 2026 · Google
★★★★★
"Definitely recommend for any windows installation in Los Angeles. Love the new windows. Great price and reliable service! We are grateful."
S
Sydney Bati
Apr 2026 · Google
★★★★★
"So happy with the results of the window installation by Window Design Group this week! Very professional and hard working team"
G
Gina Calzada
Apr 2026 · Google
★★★★★
"Recommendations for any window repair services! An amazing work and very professional"
D
David Rojas
Mar 2026 · Google
★★★★★
"Our new windows are STUNNING!! Their team was easy to work with and gave us a great price."
J
Jennie Do
Mar 2026 · Google
★★★★★
"The team from WDG were top notch from start to finish. Friendly, respectful, professional. Beautiful windows, modern style"
Y
Yitzy Flam
Mar 2026 · Google
★★★★★
"Window Design Group installed 6 Milgard Tuscany windows and one slider in our home. Pricing was reasonable. Installation went smoothly."
T
Talia
Apr 2026 · Google
★★★★★
"Very good experience with the windows replacement"
C
Chali
Apr 2026 · Google
★★★★★
"Thank you for the help. Great work, and lovely design"

"They quoted us, installed the replacement windows the next month, came back six months later to check everything. I have recommended them to four neighbors since."

Sarah K. · Westlake Village · 2024
Frequently Asked

Common replacement windows questions, answered.

How much do replacement windows cost in Southern California?

Cost depends on style, material, and size. Our vinyl replacement windows start at competitive prices — and we are currently running 40% off premium windows plus 0% financing for up to 84 months. Free in-home estimates, no hidden fees, no surprises.

How long does a typical window installation take?

Most window replacements are completed in a single day by our factory-trained install crews. For whole-home jobs (10+ windows), expect 1-2 days. We give you an exact timeline at the free consultation.

What types of replacement windows do you offer?

Full Milgard lineup — Tuscany Series, Style Line, Trinsic, Ultra fiberglass, and Aluminum — plus AMI. Double-hung, slider, casement, picture, bay, and garden window styles. Vinyl, wood, aluminum-clad, fiberglass.

Do you have a minimum number of windows?

Yes — two-window minimum on every job. We do not do single-window swaps; the consultation, measurement and install economics only work at 2+ windows.

Do you install windows yourself or use subcontractors?

Every install is done by our own factory-trained Milgard-authorized crews. Never subcontracted. Three generations of in-house family installers.

What kind of warranty do you offer?

Lifetime workmanship warranty from us, plus Milgard Full Lifetime Warranty for original homeowners covering parts AND labor as long as you own the home. BBB A+ Accredited, CSLB licensed.

Will new windows really cut my energy bill?

Yes — modern insulated E-glass has about significantly better energy performance of single-pane originals. Difference shows up immediately in summer cooling costs across LA Basin, Conejo Valley, and Inland Empire.

Real WDG Project

Before · After. Same room. Same family team.

Drag the slider to reveal what new Milgard windows do for a Southern California home — natural light, cleaner sightlines, energy performance you can feel in the first power bill.

After: New Milgard windows installed

Before: Original windows
Before
After

A Westlake Village whole-home Milgard Tuscany Series install — photographed by our team.


Start your replacement windows project

A real number. A real visit. No pressure to decide that day.

Tell us how to reach you. One of the family team will call to schedule a free in-home consultation — usually within the same business day.

Ready when you are

Bring us into your home. We will bring fifty years of craft.

One visit. Real measurements. Real numbers — for windows, doors, shutters or shades. No pressure to decide that day.

Family Team · 50 Combined Years