Andersen 100 Series: Specs, Testing Data & Idaho Fit

Specifications & Testing Data

What the 100 Series Actually Is

Let's get the headline out of the way: the Andersen 100 Series is the window Wood Windows Inc sells more of than anything else — more than any Marvin, Milgard, or even Andersen's own 400 Series. After 46 years of putting windows into Treasure Valley homes, that is not a small statement, and it comes down to the material.

The 100 Series is built entirely from Fibrex, Andersen's proprietary composite. By weight it is about 40% wood fiber — mostly reclaimed sawdust from Andersen's own wood-window plants — locked inside 60% thermoplastic polymer. Every wood cell is filled and encased, so the material takes the strength and thermal stability of wood without the rot, and the low maintenance of vinyl without the softness. Andersen's published claim is twice the strength of vinyl; the practical result is a frame that stays rigid under a sash, holds a weathertight seal, and does not creep in heat.

In Andersen's lineup the 100 Series sits at the entry point, below the 200 Series and 400 Series (both wood core with vinyl cladding) and well below the A-Series and E-Series architectural lines. Do not read "entry" as "builder grade." Read it as the line Andersen designed to beat vinyl at vinyl's own game.

The Numbers That Matter

Andersen publishes NFRC total-unit ratings by product type and glass package, and the 100 Series data (2024-25 guide, revised October 2025) is worth reading closely:

Values are U-factor / SHGC, no grilles. Full-divided-light grilles add roughly 0.01–0.02 to U-factor.

Two takeaways. First, HeatLock — a room-side coating that reflects heat back into the house — is the single biggest lever on this line, worth 0.04 of U-factor for a small upcharge. We order it on nearly every 100 Series job in Idaho. Second, ENERGY STAR Version 7.0 moved the Northern-zone U-factor line down to 0.22, so standard dual-pane 100 Series units certify in the North-Central zone but not Northern. Andersen has since added an "Enhanced" Low-E package to the casement and picture tables that tests as low as 0.15–0.19; availability and lead time in our market vary, so ask us before you count on it.

Structurally, the single-hung is Hallmark certified to Class LC-PG30 (DP +30/-30) at a tested size of 143.5 by 71.5 inches — a very wide test unit, which means typical residential sizes have headroom. Air infiltration meets the 0.2 CFM/sq ft code ceiling. Exterior colors run to five, including Black and Dark Bronze; interiors come in four.

Where It Fits in Idaho — and Where It Doesn't

The 100 Series is the default window in new Treasure Valley subdivisions for good reason: a black or dark bronze exterior with a white interior is the look production builders and their buyers want, and vinyl cannot deliver dark exteriors without warranty headaches. On replacement work it shines in the 1990s–2010s housing stock across the valley, where original vinyl or aluminum sliders are failing and the homeowner wants a visible upgrade without a custom-window budget. HOAs that prohibit "vinyl windows" on street-facing elevations generally accept Fibrex, which has settled more than one architectural-review argument for us.

Where we steer people elsewhere: if you want stained wood interiors, this is not your window — go to the 400 Series. Historic North End and East End homes under design review usually need the deeper profiles of clad-wood. Very large fixed glass and unusual shapes push past the 100 Series size chart into the A-Series or E-Series. And on a strict budget for a rental or a flip, a Milgard vinyl unit hits code with less money out the door, and we will quote it alongside the 100 Series without a sales pitch.

Warranty and Service, Locally

Andersen backs the 100 Series with its Owner-to-Owner limited warranty — 20 years on glass, 10 years on non-glass components — transferable to the next owner without paperwork. Fibrex itself carries Andersen's promise that it will not flake, blister, peel, or corrode, and that is borne out by the oldest Fibrex units we service, which look the way they did on delivery day.

Warranty service on any Andersen product we sell is handled by Wood Windows employees working out of our Garden City shop, not a third-party service network. If a balance or a lock ever fails, the crew that installed your windows is the crew that comes back.

Want a line-by-line quote with the exact NFRC label values for your openings, or a side-by-side against the 400 Series or Milgard? Use the form on this page or call (208) 376-2200.

Last reviewed 2026-09-10 by Wood Windows Inc — (208) 376-2200