Four frame materials, four different answers for a New York building. Sightline, energy, size, Landmarks, lifespan, cost — and which we install where.
Aluminum when the openings are large, the look is slim and modern, or the facade is exposed. uPVC when the job is a rental or a multifamily program and cost per opening decides. Wood or clad wood when the building is landmarked or the house is traditional. Fiberglass when you want the stability of clad wood at a lower price and a factory finish is fine. The material moves the price more than the operating type does, so choose it first.
| Feature | Aluminum (thermally broken) | uPVC | Wood / Clad Wood | Fiberglass |
|---|---|---|---|---|
| Sightline / frame width | Slimmest | Widest | Middle | Middle |
| Thermal performance | Good with thermal break; best with triple glass | Best per dollar | Very good | Very good |
| Maximum lite size | Largest | Smallest | Medium | Medium |
| Finish | Powder coat, any RAL; anodised | White, a few laminates | Paint or stain inside; clad or paint outside | Factory paint |
| Maintenance | None | None | Wood needs paint; clad needs none | None |
| Landmarks (LPC) street facade | Rarely, except steel-look | Rarely | The usual approval | Sometimes, if profile matches |
| Lifespan | 40+ years | 25–35 years | 50+ years maintained | 40+ years |
| Movement with temperature | Low | Higher; long units can bow | Low | Lowest |
| Where we install it | Facades, new construction, custom houses, large lites | Rentals, multifamily programs, budgets | Landmark districts, brownstones, houses | Houses where clad wood is over budget |
| Systems we carry | Cortizo, Reynaers, Alutech, Everest, Alumil, Kleidco, Kawneer | Aluplast | Pella, Marvin, Andersen | Pella and Marvin fiberglass lines |
| Relative cost | High | Lowest | Highest | Middle-high |
Aluminum is strong for its weight, which is why it makes the thinnest frames and the largest lites — the Reynaers SlimLine 38 arches on Ocean Parkway show a 33-millimetre fixed-frame sightline carrying triple glazing. Its weakness is that it conducts heat, so every aluminum window worth buying is thermally broken: a polyamide strut separates the inside and outside halves of the profile. Without the break, aluminum is cold and condenses; with it, a good European system meets any New York energy code and can carry triple glass. See aluminum windows.
It is the material for facades and new construction — The Anable in LIC, 2535 Frederick Douglass in Harlem — and for custom houses that want big glass. It takes any RAL colour. It is not usually approved on a landmarked street facade, because it did not exist when the buildings were built; steel-look aluminum is the exception on some industrial buildings.
Rigid PVC profile, steel-reinforced, multi-chambered. The chambers make it the best thermal performer per dollar, and it needs no maintenance. It is also the widest frame of the four and the most limited in size and colour: white is standard, a few foil laminates are available, and a long sash can bow in summer sun if it is under-reinforced. It is the right answer for a rental or a multifamily program, where cost per opening across a hundred units decides and nobody is judging sightlines — The Elston in the Bronx, twenty-five units of Aluplast tilt-and-turn. See uPVC windows.
Wood is the original material of every New York window before 1950, which is why it is what the Landmarks Preservation Commission expects on a historic street facade. Solid wood inside and out needs paint every few years; clad wood — aluminum or fiberglass skin outside, wood inside — needs none and is what we install in most landmark work: Pella on Hoyt Street, Marvin Ultimate on East 70th. Wood insulates well, is stable, and can be profiled to match an original exactly. It is the most expensive of the four and the one that lasts longest maintained. See wood and clad windows.
Pultruded fiberglass frames — Pella and Marvin both make lines — expand and contract at almost the same rate as glass, which makes the seals last and the frames the most dimensionally stable of the four. They insulate nearly as well as uPVC, take a factory paint finish, and sit between uPVC and clad wood in price. They are a good answer for a house where clad wood is over budget and uPVC is too heavy-framed. They are less common in our work than the other three; ask if you want them priced.
Landmarked brownstone or townhouse, street facade: clad wood, matched to the original. Rear facade: whatever the owner wants, often aluminum for the big openings. Rental or affordable multifamily: uPVC, floor by floor. Condo or co-op with a board spec: whatever the spec says, usually aluminum or clad wood. New construction and facades: aluminum. Custom house with large lites and slim frames: aluminum; traditional custom house: clad wood or fiberglass. Oceanfront: aluminum with marine-grade finish, or fiberglass. See window replacement in NYC for how each job runs.
uPVC and fiberglass frames insulate best per dollar; thermally broken aluminum matches them only with a good thermal break and, usually, triple glass. But the glass matters more than the frame: a Low-E argon unit in any of the four beats clear glass in the best frame.
Not if they are thermally broken. Old aluminum windows without a thermal break conduct heat straight through and condense; every aluminum system we install has a polyamide break and meets the energy code.
Wood or clad wood matched to the original on street facades in historic districts. Aluminum and uPVC are rarely approved on the street side; they are common at the rear.
Wood, maintained, then aluminum and fiberglass at 40-plus years, then uPVC at 25 to 35. Hardware and seals usually need attention before any of the frames do.
uPVC, then fiberglass, then aluminum, then clad wood, like for like. The material moves the price more than the operating type. We quote from a survey rather than publish per-window prices.
Aluminum Windows uPVC Windows Wood & Clad Windows Casement vs Double-Hung vs Tilt-and-Turn Window Replacement NYC
About this page. Written by Alex GC Inc. d/b/a Alex Glass Construction and reviewed before publication by Aleksandr Chernovolenko, Managing Partner, with our design and estimating lead and a field foreman. Our foremen hold the NYC DOB Site Safety Training supervisor card and our crews the 40-hour worker card; we are certified to fabricate, install and service Alutech and Everest aluminum systems. Facts are drawn from our own projects, manufacturer test data and the applicable codes; where we are giving an opinion, we say so. Last reviewed September 2026. Credentials
Send a photo of the building and tell us what it is — landmark, rental, co-op, house. We will tell you which material fits, which the approvals allow, and quote it.
