If your windows are drafty, foggy, or original to a house built before 1990, you've probably wondered what it would cost to replace them. The answer depends on more variables than most homeowners realize, and quotes can vary by 50 percent or more for the same house depending on the contractor, the materials, and what's included.
Here's what window replacement actually costs in Delaware in 2026, what changes the price, and how to get a quote you can trust.
Average Window Replacement Costs in Delaware (2026)
For installed windows in Wilmington, expect these per-window ranges:
| Window type | Per window installed | Whole house (20 windows) | |---|---|---| | Vinyl double-hung (standard) | $600 to $1,000 | $12,000 to $20,000 | | Vinyl casement or slider | $700 to $1,200 | $14,000 to $24,000 | | Fiberglass | $1,000 to $1,800 | $20,000 to $36,000 | | Aluminum-clad wood | $1,400 to $2,500 | $28,000 to $50,000 | | Bay or bow windows | $2,500 to $5,000 each | varies |
Most Wilmington homes end up with vinyl double-hung windows. They look traditional, perform well in Delaware's climate, and hit a price point most homeowners can finance comfortably. For higher-end neighborhoods or historic districts, fiberglass or aluminum-clad wood are usually the right call.
What Affects Your Quote
Window Size and Type
Larger windows cost more. So do specialty shapes (arched, octagonal, custom) and operating styles. A standard 32 by 54 inch double-hung is the cheapest baseline. Anything larger or more complex adds 20 to 100 percent.
Frame Material
The big four:
- Vinyl: cheapest, low maintenance, good thermal performance. Can warp under extreme heat in dark colors.
- Fiberglass: strong, stable, narrower frames (more glass), holds paint well. More expensive than vinyl.
- Aluminum-clad wood: premium look, real wood interior, durable cladding outside. Most expensive.
- All wood: rare in new windows, requires the most maintenance.
For Delaware's mix of humid summers and cold winters, vinyl and fiberglass perform especially well. All-aluminum frames are not recommended in our climate. They conduct cold and form condensation easily.
Glass Package
The glass itself is one of the biggest cost drivers. Standard double-pane glass with low-E coating and argon gas is the baseline. Upgrades include triple-pane glass (better thermal and acoustic performance, $100 to $200 more per window), specialty low-E coatings tuned for our climate, laminated glass for security or sound reduction, and decorative grids.
For Wilmington homes, double-pane low-E with argon is the right baseline. Triple-pane is worthwhile only for homes near busy roads or in unusually cold microclimates.
Installation Type
Two main approaches:
- Insert (pocket) installation: new window slides into existing frame. Faster, cheaper, less disruptive. Loses about 1 inch of glass area per side. Best when existing frames are sound.
- Full-frame replacement: removes the entire existing window, frame, and trim. More expensive and time-consuming, but lets you address rotted framing, upgrade insulation, and install windows of different sizes. Required when frames are damaged.
A reputable contractor inspects your existing frames and recommends the right approach. Be wary of any contractor who quotes one approach without inspecting first.
Number of Windows
Most contractors offer per-window discounts as job size grows. A whole-house replacement of 20 windows usually prices out 10 to 15 percent below the same windows ordered five at a time.
Hidden Costs to Watch For
Quotes that look cheap often leave things out. Make sure yours includes:
- Removal and disposal of old windows
- Permits (Delaware requires them for full window replacement projects)
- Interior trim repair and painting
- Exterior trim, sealing, and flashing
- Manufacturer warranty registration
- A written workmanship warranty
Trim work is the line item most often forgotten. After old windows come out, the casing inside and outside may need patching, painting, or replacement. Some contractors include this. Some bill it separately at the end.
Energy Savings: What's Realistic
New windows are often pitched as a way to "cut your energy bills in half." For most Delaware homes, that's exaggerated.
Realistic savings for replacing old single-pane or worn double-pane windows with modern Energy Star windows: 10 to 20 percent on heating and cooling. For a typical $200 per month combined bill, that's $20 to $40 per month, or $240 to $480 a year.
That's real money over 20 years, but it doesn't pay back $20,000 in window costs through energy savings alone. The real value of new windows is comfort (no drafts, more even temperatures), curb appeal, lower maintenance, and resale value.
Resale Value
According to Remodeling magazine's Cost vs. Value report, vinyl window replacement returns 65 to 75 percent at resale, and fiberglass returns slightly more. New windows are highly visible to buyers and frequently called out by inspectors. Replacing old windows before listing usually pays back through faster sales and stronger offers.
How to Get an Honest Quote
Window quotes vary widely. To compare apples to apples, ask each contractor for the exact brand and model of window proposed, the glass package details (panes, gas, coatings), the frame color (interior and exterior), the installation type (insert vs full-frame), itemized labor and materials, and warranty terms in writing.
Watch for "lifetime warranties" with fine print that limits actual coverage. Read the warranty document, not the marketing.
Ready for Real Numbers on Your Windows?
At TB Home Improvements, we provide free, itemized window quotes for Wilmington-area homeowners. We measure every opening, inspect frames for damage, and walk you through every spec before you commit.