Sierra Pacific Monument & Westchester Hung Windows: Specs, Testing Data & Idaho Fit

Wood Windows Inc is not an authorized Sierra Pacific dealer. We service, repair, and replace Sierra Pacific windows and doors throughout the Treasure Valley.

Specifications & Testing Data

Wood Windows Inc is not an authorized Sierra Pacific dealer. We service, repair, and replace Sierra Pacific windows and doors throughout the Treasure Valley. If your home has Sierra Pacific single or double hung windows, this page explains which version you likely have and what to expect from it.

What Monument and Westchester Actually Are

Sierra Pacific builds its aluminum-clad wood hung windows in three tiers, and homeowners rarely know which one they own. Monument is the top of the stack: a single or double hung designed for architectural, historic, and light-commercial work. It has no jambliners at all, inside or out, so the view through the opening is framed entirely in wood, and the bottom sash side-loads out of the frame for cleaning rather than tilting. It came in full-radius and arched configurations, with dual sash locks standard and hardware in six finishes, and was offered clad or with an all-wood exterior. Westchester is the residential hung beneath it, with a concealed jambliner, a fixed top sash on the single hung and two tilt-in sashes on the double hung, clad in 0.055-inch extruded aluminum. The third tier is the H3 double hung, which uses the company's aluminum-vinyl-wood Fusion Technology frame.

Sierra Pacific also sells Transcend sash kits, replacement double hung sashes sized to an existing opening and installed from the room side without touching frame or trim, clad in the same 0.055-inch aluminum. The Monument Horizontal Slider, a two- or three-lite gliding window on a 4-9/16-inch jamb, is now listed as obsolete on the company's site.

All of it shares the same materials story: CoreGuard Plus-treated wood in eight species (pine standard), powder-coated extruded cladding in 50 colors across four collections, Cardinal Low-E glass on a no-metal TrueWarm foam spacer, and factory Ultra Stain or Ultra Coat interior finishes on newer production.

The Numbers That Matter

Sierra Pacific does not publish a single U-factor for Monument on its product pages; thermal and structural data live in the per-product Architectural Design Manual and in the NFRC directory. As a class, clad-wood double hungs with dual-pane Low-E and a foam spacer land in the high 0.20s U-factor, and triple glazing brings them into the low 0.20s. Hung windows test a step worse than casements of identical construction because a sliding sash cannot compress its weatherstrip. If your label is gone, the CPD number etched in the glass spacer will pull the exact rating from the NFRC search.

Structurally, Monument was engineered for light-commercial loads, which is why it turns up on schools, civic buildings, and larger custom homes. Westchester carries standard residential ratings. Verify per unit before assuming a same-size replacement will match.

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

Monument's natural habitat here is the North End and East End of Boise, Nampa's older historic blocks, and Caldwell's downtown residential streets, where design review or an owner's taste demanded a true double hung with wood showing on every surface. It also went into 2000s-era custom homes on the bench and in the foothills whose designers preferred hung windows over casements for a traditional elevation. Westchester is more common in semi-custom production homes of the same period.

What ages on them is predictable. Balances weaken and a sash drifts down or will not hold open. Meeting-rail and sill weatherstrip flattens, and winter air leakage climbs; that is the Idaho-specific weakness of any hung window, since our 50-degree daily swings work the sash up and down the jamb thousands of times a year. Insulated glass seals fail on south and west exposures somewhere in the 12-to-20-year range. The powder coat generally lasts, though dark colors chalk sooner on unshaded walls.

Where Monument is not the right target for like-for-like replacement is a house where the owner is tired of the hung format itself. A casement of the same construction seals better and tests better, and on a rear elevation with no design review we will say so. Where a historic district requires a hung profile, Monument's replacement should be another real clad-wood or all-wood double hung, not a vinyl insert.

Repair or Replace — Our Path

Balances, sash locks, tilt latches, and weatherstrip are replaceable on Westchester and H3 hungs and, with more labor, on Monument. Fogged glass goes back in as a matched insulated glass unit. When frames are twisted, rotted at the sill, or the owner wants a whole-house energy upgrade, we quote from the clad-wood and all-wood hungs we carry: the Andersen 400 Series tilt-wash double hung for the most common match, the Marvin Ultimate double hung for extruded cladding and species choices nearest Monument, and the Kolbe Heritage Series when a historic board wants all wood outside as well as in.

Warranty and Service, Locally

Under Sierra Pacific's residential wood/clad warranty for products made since May 2017, dual insulated glass is covered 20 years, triple glass 10, parts 10, labor 2, wood deterioration 20, and AAMA 2605 finish 30 years against cracking and checking, transferable to subsequent owners. Warranty claims go to Sierra Pacific at 800-824-7744. For everything else, including out-of-warranty glass, balances, and full replacement, our Garden City crews handle the work with employee installers only, as we have for 46 years.

Sash dropping or glass fogging on a Sierra Pacific double hung? Request a quote on this page or call (208) 376-2200.

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