Slim-frame aluminum window detail against a minimalist interior wall

Material thesis

Why aluminum

Premium windows and doors come in five materials: aluminum, vinyl, wood, fiberglass, and steel. Each has a place. Thermally-broken aluminum is the working premium tier: slim enough for modern sightlines, structurally strong enough for large glass, and finished in a way that does not need maintenance. Sourced direct, it lands below the brand-name aluminum lines for the same spec.

The cert stack

Crateworks aluminum windows and doors carry the full cert stack disclosed on every quote. The IDs below are the same ones cited on the product pages and in the architect resources.

  • NFRC certified
  • Miami-Dade NOA
  • Energy Star
  • CSA A440-22
  • AAMA 2605
  • STC 56
  • Hurricane impact

Crateworks holds NFRC certifications across casement, tilt-turn, fixed-picture, awning, sliding, bifold, entry, swing, and arc-top configurations. Cert IDs disclosed on quote.

Miami-Dade NOA #25-0911.01 — HVHZ Large + Small Missile Impact, expires 2030-12-24.

US Energy Star registered FXC-M-3, valid through 2029-07-20.

CSA A440-22 cold-climate certified #80224506. U = 0.236 to 0.387 depending on configuration.

AAMA 2605 PVDF coating, 20-year finish warranty.

STC 56 acoustic per ASTM E90.

Hurricane impact tested, cert #QCT25-7593.01.

Material comparison

CrateworksAluminumThermally-broken
BudgetVinylPVC
PremiumWoodOften clad
Mid-premiumFiberglassComposite
LuxurySteelItalian-anchored
01Sightline
Slim. Carries large glass on a narrow frame because aluminum is structurally strong.Thick. Vinyl needs bulk to hold its shape, so frames are wider, glass area smaller.Medium to thick. Wood needs section depth for strength, and grain visibility shifts the read of the frame.Medium. Stiffer than vinyl, slimmer profiles possible, but not as thin as aluminum or steel.Narrowest. Steel is the structural king of slim sightlines.
02Upkeep
None. Baked-on finish on metal that does not rust, warp, or rot.None mechanically, but UV degrades the finish over time. Color is dyed into the plastic, so it fades unevenly.Ongoing. Stain, paint, or clad to keep weather out. Interior face is decorative.Low. Finish holds well but can be repainted.Finish-dependent. Steel rusts when the coating fails. Coastal and humid climates require attention.
03Lifespan
Multi-decade. Frame outlasts the IGU. Replace glass without replacing frame.15 to 25 years before frame degradation shows. Replacement, not repair.Long if maintained. Failure starts at joints and exposed end-grain.Multi-decade. Stable across temperature swings.Multi-decade if finish is maintained. Patina is sometimes desirable, sometimes not.
04Cost
Direct-source premium tier; below brand-name aluminum (Marvin, Andersen) for equivalent spec.Cheapest entry. The mainstream replacement-window category in the US.Premium-to-luxury. Most expensive when clad (aluminum exterior, wood interior).Mid to premium. Above vinyl, below clad-wood and steel.Luxury tier. Italian steel casements anchor the top of the market.
05Best for
Slim modern sightlines, large openings, coastal and humid climates, custom shapes.Budget-driven projects on rectangular openings where sightlines do not matter.Traditional architecture, projects that want the warmth of a wood interior, historic restoration.Cold-climate budget-conscious premium, where vinyl is too thick but clad-wood is too expensive.Heritage architecture, the very thinnest sightline, the prestige story.

Premium without the brand tax

A premium window passes through several margin layers between the source and your project: importer, distributor, dealer, showroom. On premium aluminum that markup is roughly 30 to 50 percent of the retail price. Crateworks operates source-direct, so the same quality-tier aluminum, the same IGU options, and the same hardware land at a price that does not include the showroom overhead.

The brand tax is real value on the day a dealer comes to replace a failed unit; the rest of the time it is overhead.

We trade dealer service for documented turnaround and direct supplier coordination. If you are weighing this against established brands, the comparison page for Marvin, Andersen, and Western Window Systems lay out the tradeoffs without disparagement. For the steel-vs-aluminum question, see Crateworks vs Pinky's.

Where aluminum wins, where it doesn't

Aluminum wins on slim sightlines, large openings, coastal and humid climates, custom shapes, and price-to-spec ratio. It does not win on the absolute thinnest sightline, where Italian steel casements hold the top position, and it does not win on the warm interior face of a wood-clad frame for a traditional library or a heritage parlor. The right material depends on the room and the architecture, not on a single answer.

Common questions

A thermal break is an insulating barrier set inside the aluminum frame that physically separates the outdoor metal from the indoor metal. Aluminum conducts heat well, so a plain aluminum frame performs poorly thermally. A thermal break stops that transfer, which is why thermally-broken aluminum is comparable to wood and fiberglass on energy and how it qualifies for code in modern climates.
Steel sits above aluminum on the prestige ladder, anchored by Italian steel casement systems that hit the absolute thinnest sightline. Aluminum is the working premium tier: thinner than vinyl, wood, or fiberglass, structurally sound for large glass, maintenance-free, and at direct-source pricing it lands below the brand-name aluminum incumbents for equivalent spec. For most premium-grade residential and trade work, aluminum is the right tool. Steel is the right tool when prestige or absolute sightline narrowness matters more than maintenance and price.
A typical premium window passes through multiple layers before it reaches a project: the supplier, an importer, a dealer, and a showroom. Each stage carries margin. Sourcing direct removes the dealer and showroom margins, which is roughly 30 to 50 percent of the retail price on premium aluminum. Crateworks operates with that margin removed, so the same spec at the same quality tier costs less by the time it reaches your opening.
Crateworks sources the same grade of thermally-broken aluminum as the premium aluminum lines from established brands. The aluminum, the IGU options, the hardware, and the engineering are all comparable. Where the brand-name lines have a longer track record, established dealer service infrastructure, and a familiar warranty story, Crateworks competes on price and on direct sourcing access. See the comparison pages for Marvin, Andersen, and Western Window Systems for the specific tradeoffs.
Yes, when it is thermally-broken and paired with a high-performance IGU. The thermal break is what makes the frame perform in cold weather, and the glass package carries the rest. A thermally-broken aluminum window with a triple-pane low-E IGU meets IECC climate zone 4 to 6 prescriptive U-factor requirements. For climate zones 7 and 8, the IGU spec and the frame depth need to step up; we confirm what we can document before order.
The brand tax is the cost added to a window between the source and your project by the dealer network, the marketing budget, the showroom rents, and the sales commissions that the brand needs to operate. None of it changes the product. The brand tax is real value on the day a unit fails and a local dealer comes to replace it, and it is purely overhead on the day you order. Crateworks runs without it, and we make replacement work through documented turnaround instead of a dealer.

Specify your project

See the spec for your project.

Send the opening schedule. We return a package quote with the aluminum profile, the IGU spec, finish tier, and lead time.

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