Compare premium fiberglass, vinyl, composite, wood-clad and aluminum-clad replacement windows from Marvin, Pella, Andersen, ProVia and Simonton.
GS Exterior Experts helps Colorado homeowners select the right window material, style, glass package and installation method for their homes. From the initial measurements through flashing, sealing and finish work, our team manages the complete window replacement process.
Based in Littleton and serving homeowners throughout South Metro communities and the Front Range, GS Exterior Experts has worked on Colorado homes since 1999.
1999
Serving Colorado since 1999
Over 25 years on Front Range homes
5★
Google-rated reputation
Trusted by Littleton homeowners
5
Multiple premium window brands
Marvin · Pella · Andersen · ProVia · Simonton
In-House
Professional installation
Measurement through flashing and finish work
Littleton
Where our crews are based
Serving Littleton, CO & Surrounding Areas
A better way to choose windows
Frame material, glass package, window style, exterior exposure,
opening condition and installation method all affect how a finished window looks and performs.
GS Exterior Experts gives homeowners access to multiple window manufacturers rather than pushing every project toward one product.
We help you compare the differences between Marvin, Pella, Andersen, ProVia and Simonton based on your home, design preferences, performance goals and budget.
Whether you are replacing aging aluminum windows, upgrading builder-grade vinyl windows or completing a full exterior renovation, our team will help you develop a window package that fits the project.
Fiberglass, vinyl, composite, wood or clad — each behaves differently in Colorado sun.
Glass packages and climate considerations, by façade and exposure.
Casement, double-hung, slider, picture,
bay and specialty shapes.
Insert into the existing frame, or full-frame down to the rough opening.
Good, better and premium approaches — including how many openings you take on at once. See what drives window cost.
The lineup
Different window manufacturers serve different needs. Some homeowners prioritize fiberglass construction and dark exterior colors. Others want natural wood interiors, narrow vinyl frames, architectural customization or a more budget-conscious replacement option. Our team helps you compare the available brands without assuming that one manufacturer is automatically right for every home.
Marvin is an excellent option for homeowners seeking premium fiberglass, wood-interior or aluminum-clad window products — including narrow sightlines and dark exterior finishes.
Essential
Ultrex fiberglass interior and exterior
Elevate
Wood interior with Ultrex fiberglass exterior
Ultimate
Architectural wood interiors with exterior cladding
Fiberglass · Wood · Aluminum-clad
Pella covers a wide range of materials, interior finishes and price points, which makes it a practical starting point when a homeowner wants to weigh several directions side by side.
Impervia
Fiberglass frames and sashes
Lifestyle
Wood interiors with a protected exterior
250 Series
Vinyl replacement windows
Fiberglass · Vinyl · Wood
Andersen spans composite frames through architectural wood-interior products, with a deep set of exterior colors and patio-door options to coordinate with.
100 Series
Fibrex composite frames
400 Series
Generally wood interior with a protected exterior
E-Series
Wood interior with aluminum-clad exterior
Fibrex composite · Wood · Aluminum-clad
A practical choice when windows and doors are being replaced in the same project, with a range of energy-efficiency configurations.
Endure
Vinyl replacement
Aspect
Vinyl replacement
Aeris
Wood-clad
Vinyl · Wood-clad
A streamlined vinyl profile that works well for full-home replacement where low maintenance and value lead the decision.
DaylightMax
Slim vinyl profile, maximized glass area
Vinyl
Product lines, styles, colors, glass packages and configurations vary by manufacturer, opening size and project location. GS Exterior Experts will confirm availability and specifications before products are ordered.
Side by side
Often a strong fit for
Common material options
Premium renovations, fiberglass construction, wood interiors, architectural projects
Fiberglass, wood and aluminum-clad
Homeowners seeking a broad selection of materials, features and price points
Fiberglass, vinyl and wood
Composite windows, traditional wood interiors and customized architectural designs
Fibrex composite, wood and aluminum- clad
Energy-efficient replacement projects and coordinated window-and-door packages
Vinyl and wood-clad
Value-focused, low-maintenance vinyl window replacement
Vinyl
There is no single window brand that is best for every project. The right choice depends on the condition of your existing openings, your preferred frame material, the architecture of your home, desired interior and exterior colors, glass-performance goals and total budget. During your consultation, we can help you compare product lines side by side and narrow the options to the windows that make the most sense for your property.
Built for this climate
Colorado windows must perform through intense sunlight, changing temperatures, wind, snow and seasonal storms. A south- or west-facing window may need a different glass package than a shaded window on the north side of the same home — window size, elevation, surrounding trees, roof overhangs and interior comfort concerns should all be considered.
We help you evaluate available Low-E coatings, dual- or triple-pane glass, gas-filled insulating units and other performance options based on your home and budget.
Frame materials respond differently to sunlight and changing temperatures. Fiberglass and composite can be useful where dimensional stability and dark exterior finishes matter; vinyl is efficient and low-maintenance at a more accessible price point.
Even a premium window can
underperform when it is installed
incorrectly. Proper opening
preparation, flashing, sealing and integration with the surrounding siding are essential parts of a successful replacement.
Performance should be reviewed using the exact product configuration, not general marketing. We select products certified for the applicable climate zone and review NFRC ratings before ordering.
Glass package and configuration do more for comfort than any single spec on a brochure.
Frame materials
A popular choice for strength, dimensional stability, low maintenance and narrow profiles — used inside and out, as with Marvin Essential, or as a durable exterior paired with a wood interior, as with Marvin Elevate.
Rigid, dimensionally stable frames
Narrow profiles, more glass
Holds dark colors in strong sun
Lower maintenance over time
Examples
Marvin Essential · Marvin Elevate · Pella Impervia
Low-maintenance construction, good thermal performance and a wide range of price points — a
practical route to an efficient full-home upgrade without premium wood-interior costs.
Most accessible price point
Solid thermal performance
Very low maintenance
Works well for full-home replacement
Examples
Simonton DaylightMax · ProVia Endure · select Pella
Wood interiors provide warmth, depth and a traditional appearance suited to higher-end and architecturally detailed homes. Exterior cladding protects the wood from direct weather exposure — available cladding varies by collection and may include fiberglass, vinyl, composite or aluminum.
Natural interior appearance
Suited to architectural homes
Premium interior finishes
Exterior protection through cladding
Examples
Marvin Elevate · Pella Lifestyle · Andersen 400 Series
Composite windows combine multiple materials for a stable, low-maintenance frame. Andersen’s Fibrex material is used throughout its 100 Series — a narrow, modern alternative to traditional vinyl.
Stable frame, narrow profiles
Low maintenance
An alternative to traditional vinyl
Broad color availability
Examples
Andersen 100 Series (Fibrex composite)
Clean profiles, architectural flexibility and extensive exterior color options — often selected for contemporary homes, large openings and custom projects. Many aluminum-clad collections use natural wood on the interior.
Architectural flexibility
Clean, minimal profiles
Suited to large openings
Custom exterior colors
Examples
Marvin Ultimate · Andersen E-Series
Bring us the openings you are least happy with. We will tell you what changes with each material — and what does not.
Assessment
Some problems can be corrected without replacing every window. During the evaluation we inspect the existing units and help you determine whether full replacement is appropriate.
◆ Drafts around the frame or sash
◆ Difficult to open, close or lock
◆ Water staining around the opening
◆ Single-pane or aging aluminum windows
◆ Excessive outside noise
◆ Fog or moisture between glass panes
◆ Cracked, warped or rotted frames
◆ Failed seals or deteriorated caulking
◆ Rooms noticeably hotter or colder
◆ A style or color that no longer fits
Window styles
Hinged at the side and cranked outward for full-opening airflow. Good over sinks and in hard-to-reach spots.
Both sashes operate and tilt in for cleaning. The most common replacement style on Front Range homes.
Bottom sash raises, top stays fixed. A classic look at a lower price point per opening.
Glides left or right along a track. Well suited to wide openings and basement egress.
Does not open, so it maximizes glass and view. Often paired with operable units on either side.
Hinged at the top and opens outward — useful for ventilation even during light rain.
Projects outward to add dimension, light and sometimes seating. Structural details matter here.
Arches, circles and angled shapes for gables and stair walls. Built to the opening.
Installation methods
Two different scopes of work. The condition of your existing frame usually decides which one is appropriate.
Existing frame retained
A new window is installed inside the existing window frame, leaving the surrounding trim in place.
May be appropriate when
› The original frame is structurally sound
› Existing flashing is sound
› There is no major water damage
› Preserving interior trim is a priority
Trade-off:
slightly reduced glass area, since the new frame sits inside the old one.
Down to the rough opening
The existing window is removed down to the rough opening, so the opening itself can be inspected and rebuilt correctly.
Useful when
› Deterioration or water intrusion exists
› Flashing requires correction
› Window size or style is changing
› Siding is being replaced at the same time
Benefit:
framing can be inspected, water management addressed, new flashing installed and the window integrated into the exterior system.
One exterior contractor
When the two scopes are coordinated, the window flashing can be integrated directly with the weather resistant barrier instead of worked around it — and the trim details get resolved once, by one crew.
◆ Flashing integrated with the weather-resistant barrier
◆ New trim coordinated with the new siding profile
◆ One contractor, one sequence, one point of accountability
What to expect
We look at every opening, the condition of the frames and how the exterior is put together.
Brands, materials, styles, colors and glass packages — side by side, with pricing context.
Final field measurements for every unit before anything is ordered.
Scheduling, interior protection and a walkthrough of how the days will run.
Old units out, openings prepared, new windows set, flashed and sealed.
Interior and exterior trim, caulking and paint-ready detailing.
We review the installation, demonstrate window operation and provide applicable product and warranty information.
Real projects
See how different window brands, frame materials and colors look on real Colorado homes.
The homeowners wanted narrower frames and a darker exterior without giving up the wood interior. Full-frame replacement let us correct the flashing at the same time.
Full-frame
Low-E, double-pane
View Project
Every opening in the house was replaced in one phase, with casements on the west elevation to handle afternoon sun and wind exposure.
Insert
Casement + picture
Low-E, double-pane
View Project
A value-focused full-home replacement where the goal was comfort and low maintenance across eighteen openings without changing the exterior look.
Insert
18 windows
Low-E, dual-pane
View Project
In their words
The installation crew did excellent work. The quality was top-notch, and they wrapped up each day with thorough cleanup — a small thing that makes a big difference. The teamwork among the crew was evident throughout.
— Lisa Lewis · Siding + window trim project
After recently meeting with four different siding companies, we hired GS Exterior Experts to install James Hardie siding and I couldn’t be happier with our decision. From start to finish, the experience was excellent.
— Michael DeJager · Exterior remodel
Budget
Two homes with the same number of windows can land far apart. These are the variables that move the number most.
Quantity of windows
Product collection
Size & window style
Colors & hardware
Insert vs. full-frame
Manufacturer
Frame material
Glass package
Opening condition
Trim & structural repairs
Littleton Colorado · from our Pricing Guide
Energy upgrade
+$180–$230
Triple-pane with insulating gas, per project
Bay window
+$5,000–$35,000
Depending on size and style
Full-frame installation, damaged framing, new interior trim, enlarged openings and custom shapes can also affect the scope. GS Exterior Experts provides a written proposal outlining the selected products and installation work, and financing options are available for qualified homeowners.
Get a starting range online, then request an in-home evaluation when you are ready for exact product and installation pricing.
Also available
Replacing your windows is a good time to evaluate entry doors, patio doors and sliding glass doors. Coordinating the products creates a more consistent exterior and can simplify installation when several openings are upgraded at once. We can help you compare exterior- door options from ProVia, Marvin, Pella and Andersen, depending on the project.
The difference
GS Exterior Experts is a Colorado exterior remodeling company serving homeowners since 1999, with a Littleton-based team working throughout Highlands Ranch and the Front Range. Unlike a single-manufacturer sales company, we help homeowners compare multiple window brands, materials and price points — and our broader exterior experience lets us evaluate how each window interacts with the siding, trim, flashing and wall assembly around the opening.
Compare Marvin, Pella, Andersen, ProVia and Simonton rather than being pushed toward whichever single brand a contractor carries.
Windows, siding, trim and related exterior work coordinated as one scope — including how the window ties into the wall assembly.
Sunlight, weather exposure, frame material behavior and glass packages considered wall by wall, not house by house.
Receive a defined product selection, project scope and installation plan before the work begins.
Opening preparation, flashing, sealing and trim detailing get the same attention as the window you picked.
Littleton-based, working on Colorado homes since 1999, with crews who know how Front Range homes are built.
Service area
GS Exterior Experts is based in Littleton and serves homeowners throughout Columbine and surrounding South Metro communities.
Littleton
Englewood
Centennial
Highlands Ranch
Lakewood
Morrison
Columbine
Sheridan
Golden
Ken Caryl
Littleton homeowners
Ranch and split-level specifics, local projects and neighborhood notes.
Highnland ranch homeowners
Single Family, Town Homes, city projects and permitting details.
Questions
There is no single brand that is best for every Colorado home. Marvin may be a strong fit for premium fiberglass and wood-interior projects. Pella provides a broad selection of materials and features. Andersen offers composite and wood products. ProVia provides customizable replacement-window options, while Simonton is often a practical choice for vinyl replacement. The right brand depends on the home, opening sizes, desired materials, design preferences and budget.
Fiberglass and vinyl serve different needs. Fiberglass generally provides greater frame rigidity and is often selected for narrow profiles, dark colors and premium projects. Vinyl offers low maintenance and strong overall value. Product quality, glass selection and installation are important regardless of frame material.
Insert replacement places a new window inside the existing frame. Full-frame replacement removes the original frame down to the rough opening. Insert replacement may work when the existing frame is sound. Full-frame replacement is generally more appropriate when there is damage, water intrusion, poor flashing or a planned change in window size or style.
The cost depends on the manufacturer, material, size, style, glass package, finish, installation method and condition of each opening. A basic vinyl replacement window and a custom wood-interior architectural window will have substantially different price points. An in-home evaluation is the most reliable way to develop an accurate project cost.
The installation schedule depends on the number of windows, installation method, finish work and weather. Your project proposal and preconstruction plan should identify the anticipated installation duration after the windows have been manufactured and delivered.
Yes. Coordinating windows and siding can provide better access to the wall assembly and allow the window flashing to be integrated with the new weather-resistant barrier and siding system. This approach may be especially useful during full exterior renovations.
Yes, black and other dark-colored window options are available from several manufacturers. Available interior and exterior color combinations vary by product line. Dark frames should be selected based on the manufacturer’s available finish system, the home’s exposure and any applicable HOA requirements.
Energy performance is influenced by the frame, glass, spacers, number of panes, coatings, gas fills, air leakage and installation. Homeowners should review the NFRC label and verify that the exact product configuration is appropriate for the applicable ENERGY STAR climate zone. Certification can vary by product, size and glass package.
GS Exterior Experts can coordinate select patio and exterior-door products with a window replacement project. Available manufacturers and products depend on the project requirements.
Manufacturer warranties vary by brand, product line, glass package and finish. Applicable warranty information should be included with the final product selection and project documentation.
Yes. GS Exterior Experts is based in Littleton and has a dedicated Littleton window replacement page for homeowners seeking more location-specific information.
Ready to compare?
Choosing between Marvin, Pella, Andersen, ProVia and Simonton does not have to be confusing. We will help you compare materials, styles, colors, glass packages and installation methods based on your home and project goals.
Contact our Littleton-based team to schedule a window evaluation and receive a written proposal for your replacement-window project.
