Window replacement in Hempstead runs – per window installed. Here’s what Long Island homeowners actually pay, what the energy savings math looks like, and red flags in quotes.
Someone sent me a window quote last spring. $28,000 for 11 windows in a 1,400-square-foot cape cod in Hempstead. “Premium energy-efficient installation,” it said. No breakdown. No materials list. Just a number with a signature line. She almost signed it. Window replacement in Nassau County doesn’t have to be that complicated or that expensive, but you do need to know what you’re actually buying.
Quick answer: In Hempstead and the surrounding Nassau County area, a typical double-hung vinyl window replacement runs $350 to $750 per window installed. A full house of 15 to 20 windows usually lands between $6,000 and $14,000 depending on size, style, and frame condition. Permits are required for most jobs. Energy savings are real but usually overstated by about 2x.
When your windows actually need to go
There’s a difference between windows that are uncomfortable and windows that are done. Uncomfortable windows can sometimes be fixed with weatherstripping, caulk, or glazing compound, all under $100. Done windows can’t. Here’s how to tell the difference.
- Fogging between panes — that’s a failed seal, the insulating gas is gone, no repair possible
- Frames that are soft, spongy, or rotting at the corners
- Windows that won’t stay open or won’t stay shut without a latch
- Visible daylight around the frame when you look from inside at dusk
- Condensation forming on the interior glass surface in winter — not exterior, interior is the problem sign
- Single-pane glass on a house built before the 1980s
Condensation on the outside of the glass is normal in summer and not a problem. But fog or moisture between the panes? That’s done. The seal failed and there’s no way to fix it without replacing the sash or the whole unit.
Double-hung vs. casement vs. picture window: what Long Island homes usually need
Most cape cods and colonials in Nassau County have double-hung windows, the kind where both sashes slide up and down. They’re common because they’re easy to clean from inside. Casements open on a hinge like a door. They seal better because the mechanism pulls the sash tight against the frame, but they cost 15 to 25% more. Picture windows don’t open at all. They’re for rooms where you want light and a view, not ventilation.
| Window Type | Cost Per Window Installed | Best For | Ventilation |
|---|---|---|---|
| Double-hung vinyl | $350 – $700 | Bedrooms, living rooms, most walls | Good (both sashes open) |
| Casement vinyl | $450 – $850 | Kitchens, bathrooms, narrow walls | Best (full opening) |
| Picture window | $300 – $900 | Living rooms, front facades | None |
| Slider | $350 – $700 | Basements, modern homes | Moderate (half opens) |
| Bay or bow | $1,500 – $4,000+ | Living rooms (major feature) | Depends on style |
Vinyl is the default for most Nassau County replacements. It doesn’t rot, doesn’t need painting, and holds up in the salt air near the water. Fiberglass is about 30 to 40% more expensive but better for large openings. Wood is a maintenance commitment most homeowners here don’t want.
What window replacement actually costs in Hempstead right now
The quote I mentioned at the top was 2.5x higher than it needed to be. Here’s what the numbers look like in Nassau County in 2025.
| Scope | Low End | High End | What Drives It |
|---|---|---|---|
| Single double-hung window | $350 | $700 | Size, frame condition, trim work |
| Single casement window | $450 | $850 | Same plus hardware |
| Whole house (15 windows) | $6,500 | $12,000 | Window count, style mix, any frame rot |
| Whole house (20+ windows) | $9,000 | $16,000 | Large home, mix of sizes |
| Bay window replacement | $2,500 | $5,500 | Structural work, custom sizing |
| Egress window (basement) | $800 | $2,200 | Permits, excavation, well installation |
Frame damage adds cost. If a contractor opens the wall and finds rotted framing or damaged sills, that’s another $150 to $600 per window. Get that spelled out in your contract as a possible line item before the job starts.
Energy savings: what’s real and what’s marketing
Window companies like to quote savings of 15 to 25% on heating and cooling bills. That’s technically possible if your current windows are single-pane and completely failed. Replacing decent older double-pane windows? You’re realistically looking at 7 to 12% savings. On a $3,000 annual energy bill, that’s $210 to $360 a year. At a project cost of $10,000, payback time is 28 to 47 years. The comfort improvement is real. The payback math usually isn’t.
Permit requirements in the Town of Hempstead
Window replacement in Nassau County requires a building permit if you’re changing the size or location of the opening. Like-for-like replacements (same size, same location) often don’t. Egress windows, new openings, and anything that touches structural elements always require permits. The Town of Hempstead Building Department handles permits for most of the township, and processing runs 2 to 6 weeks depending on backlog. Verify directly with the building department before work starts if you have any doubt about your specific job.
Red flags in window replacement quotes
A lot of window quotes are structured to make it impossible to compare them. Watch for these.
- No manufacturer name or model number — means materials can be swapped without you knowing
- “Premium” or “high-efficiency” without a U-factor or SHGC number (those are the actual specs that matter)
- Upfront deposits over 30% before any materials are ordered
- Prices that drop 40% if you sign today — a high-pressure close worth walking away from
- No explanation of how they handle frame rot found during installation
- Labor warranty under 2 years from the installer (manufacturer warranty doesn’t cover installation)
A good quote itemizes window type, size, manufacturer, U-factor, installation scope, and what happens if they find rot. Labor and materials should be listed separately. Anything that’s just one lump number with no breakdown deserves a follow-up question.
Selective Remodeling handles window replacement across Nassau County alongside home renovations in Hempstead and full exterior projects including fiber cement siding installation. When windows are part of a bigger exterior scope, it usually makes sense to combine crews and sequence the work together.
Window replacement in Hempstead isn’t mysterious once you know the numbers. Know your window types, get quotes that list materials by spec, and don’t let anyone sell you a 25% energy savings as the main reason to buy. Replace windows because yours are done. That’s a good enough reason.