New Construction vs Retrofit Windows – Which One’s Better?

When you’re standing in your living room looking at windows that fog up every winter or feeling that cold draft seeping through the frames, the question isn’t whether you need new windows – it’s which type will actually solve your problems without breaking your budget.

The window industry loves throwing around terms like “New Construction” vs “Retrofit Windows” but what do these actually mean for your home? After helping Middle Georgia homeowners navigate this decision for two decades, I can tell you that choosing the wrong type costs people thousands of dollars and years of frustration.

Let me break down everything you need to know to make the right choice for your specific situation.

Key Takeaways

• Retrofit windows and replacement windows are the same thing. The terms are interchangeable.
• Retrofit windows install inside your existing frame without exterior siding work. New construction windows replace the full frame and require exterior access.
• The three types of retrofit windows are flush fin (Z-bar), block frame, and pocket/insert. The right type depends on your exterior material and frame condition.
• Do not install retrofit windows over damaged frames. Rot, water damage, and structural compromise require full new construction replacement.
• Retrofit installation costs 30 to 50% less than new construction in most projects, but that gap narrows significantly when new construction is paired with siding replacement.
• Both window types can achieve excellent energy efficiency when installed correctly. Glass quality and installation workmanship matter more than installation type alone.
• Look for NFRC-rated products, heat-welded frame joints, stainless steel hardware, and multi-chamber frame construction in either window type.
• At The Window Source of Middle Georgia, we assess your existing frames before recommending a window type. The right answer for your home depends on what your frames look like today, not on which product costs more or less at the showroom.

What Are Retrofit Windows?

Retrofit windows are new window units designed to fit inside your existing window frame. The frame stays in the wall exactly where it is. Only the old sash, glass, and hardware get removed. The new window slides into the existing opening and attaches to the original wood frame using screws, caulk, and weatherstripping.

This process is also called a pocket installation or an insert installation, depending on the manufacturer.

Here is the term confusion that trips people up: retrofit windows and replacement windows are the same thing. The two terms describe the same product and the same installation method. Different regions and manufacturers use different words, but they refer to identical windows. Some companies in the Southeast call them replacement windows. Others in the West call them retrofit windows. When you shop around and get quotes, you may hear both terms for the exact same product.

New construction windows are a completely different product. They come with a nailing fin, also called a mounting flange, that wraps around the exterior perimeter of the frame. This fin nails directly to the wall studs before exterior siding goes on. The window becomes part of the home’s structure, not just an insert into an existing opening.

This structural difference is what drives every other variation between the two options, including cost, installation time, energy performance, and long-term durability.

Understanding the Fundamental Difference

The difference between new construction and retrofit windows isn’t just about price – it’s about how they attach to your home and what problems they can actually solve.

New Construction Windows come with a nailing fin (also called a mounting flange) that extends around the exterior perimeter of the frame. This fin gets nailed directly to the wall sheathing before siding installation. Think of it as the window’s permanent connection to your home’s structure.

Retrofit Windows (also called replacement windows or insert windows) are designed to fit inside your existing window frame. They don’t have nailing fins because they’re not meant to attach to the wall structure – they attach to the existing wooden frame that’s already there.

This structural difference affects everything from installation complexity to long-term performance, and understanding it helps you avoid the most common mistake homeowners make: choosing retrofit when they actually need new construction, or vice versa.

Types of Retrofit Windows

Not all retrofit windows install the same way. The right type for your home depends on what material your existing exterior is made from and what condition your current frames are in.

Flush Fin (Z-bar) Windows

Flush fin windows are designed for homes with stucco, masonry, or brick exteriors. They include a large exterior flange that laps over the existing frame and covers the edge where the old window meets the wall. This flange hides any gaps or irregularities at the perimeter, which is especially useful when removing an old aluminum window from a stucco wall. Stucco almost never matches perfectly after a window removal, so the Z-bar flange covers the transition cleanly without requiring a full stucco patch.

Block Frame Windows

Block frame windows use the existing wood frame as their mounting surface. There is no exterior flange. The new unit installs directly into the wood frame opening and relies entirely on the condition of that original frame. This type works best for homes with vinyl or wood siding where the frame is fully visible, accessible, and structurally sound. If the wood frame shows any rot, warping, or water damage, a block frame retrofit is not the right choice.

Pocket or Insert Windows

Pocket windows are the most common retrofit type in wood-frame homes. They replace the sash unit while keeping both the interior and exterior trim intact. This is the lowest-disruption option available. Installation happens almost entirely from inside the home, takes one to two hours per window, and leaves your interior walls, paint, and molding untouched.

When New Construction Windows Make Sense

Your existing frames are damaged: If your current window frames show rot, water infiltration, mold, or structural compromise, retrofit windows will not solve the underlying problem. Installing a new insert into a rotted frame is like putting new tires on a car with a bent axle. The frame damage continues to worsen underneath the new window, and you will end up paying twice: once for the retrofit that did not work, and again for the full frame replacement you needed from the start.

Signs of frame damage to look for: soft or spongy wood when you press on the frame, visible dark staining or discoloration around the corners, paint that bubbles or peels near the frame edge, and drafts that come from the frame itself rather than the glass.

You want to change the window size or location: Retrofit windows are constrained by the existing opening. If you want larger windows for more natural light, a different window style in a new location, or an entirely different opening shape, new construction installation is the only viable path. The rough opening in the wall gets modified to match whatever size and style you choose.

You are already replacing siding: When siding replacement is already on your project list, new construction windows become a significantly better value. Both projects require exterior wall access at the same time. Combining them eliminates the duplication of labor, avoids having to disturb new siding later for a window replacement, and allows proper flashing integration between the window system and the new siding. The effective cost difference between retrofit and new construction shrinks considerably when you factor in this shared labor.

You want the highest long-term energy performance: New construction installation allows for complete air sealing around the entire window perimeter, from the rough opening all the way to the exterior weather barrier. The nailing fin, when correctly flashed and sealed, creates a continuous thermal barrier that retrofit installation simply cannot replicate because the original frame material remains in the wall.

When Retrofit Windows Are the Smart Choice

Your existing frames are structurally sound: When your current frames are square, plumb, rot-free, and have no history of water infiltration, retrofit windows deliver excellent performance at a lower cost. The original frame becomes part of the new window system. Its structural integrity supports the new unit and keeps the installation solid for years.

You need minimal disruption: Retrofit installation happens primarily from inside your home. There is no exterior siding removal, no flashing replacement, no landscaping disruption, and no patching of exterior wall materials. This makes retrofitting the right choice for homes with expensive exterior finishes like premium stucco, stone veneer, or custom siding that would be difficult or costly to match if disturbed.

You have a historic home or want to preserve original trim: Many older homes in Middle Georgia have unique window profiles, historic trim details, or architectural proportions that homeowners want to keep. Retrofit windows maintain the original frame dimensions and preserve the exterior appearance of the home. Full new construction replacement would alter the visual character of the window opening permanently.

Budget is a primary factor: Retrofit windows cost significantly less than new construction replacement when total project cost is compared. Labor savings alone can be substantial because there is no exterior construction work involved. For homeowners who need to replace multiple windows on a fixed budget, retrofit installation stretches the dollar further without sacrificing glass quality or thermal performance.

You want it done fast: A retrofit installation typically takes one to two hours per window. Most homes finish in a single day. New construction installation takes three to four hours per window due to the exterior work involved, and a full home project can stretch to three to five days. For occupied homes, that difference in schedule matters.

Decision Framework: How to Choose the Right Option

Answer these four questions to identify which type fits your situation.

Question 1: What condition are your existing frames in?

If your frames are solid, plumb, and show no signs of rot or water damage, retrofit windows are a viable choice. If your frames have any rot, structural damage, or history of persistent water infiltration, you need new construction replacement regardless of cost.

Question 2: Do you need to change window size or location?

If the answer is yes, new construction windows are your only option. Retrofit windows cannot modify the rough opening in the wall.

Question 3: Are you replacing siding within the next few years?

If yes, new construction windows installed during the siding project save money and deliver better integration than installing retrofit windows now and disrupting them later for siding work.

Question 4: What is your primary goal?

If your primary goal is cost efficiency and minimal disruption with good performance, retrofit windows are the right answer. If your primary goal is maximum long-term energy performance, complete frame renewal, or preparing the home for resale with a full-system replacement story, new construction windows deliver better results.

Problems with Retrofit Windows (What Can Go Wrong)

Retrofit windows work well when the right conditions are present. But there are real limitations and failure points that every homeowner should understand before committing.

Reduced glass surface area: Because the new retrofit unit sits inside the existing frame, the visible glass pane is slightly smaller than the original window. The frame of the new unit overlaps the inner edge of the old frame, which reduces the total viewable glass area. For most homeowners this difference is minor. For those who are specifically trying to maximize light, it is worth knowing before installation day.

Improper shimming causes misaligned sashes: If the installer does not shim the new unit correctly within the existing frame opening, the sashes can bind, drag, or refuse to lock properly. This is an installation quality issue, not a product defect, but it happens often enough with less experienced contractors that it deserves mention. A properly shimmed retrofit window should open, close, and latch with the same ease as a new construction window.

Wrong sealant leads to water infiltration: Retrofit installation depends on the correct sealant products applied at the perimeter between the new unit and the existing frame. Using the wrong type of caulk, applying it incorrectly, or skipping it in certain areas creates pathways for water to enter the wall cavity. Over time, this causes exactly the kind of frame rot and moisture damage that retrofit windows are supposed to avoid. Always verify that your installer uses a sealant rated for window installation and applies it continuously around the full perimeter.

Retrofit cannot fix leaks that come from the old frame: If the source of your current window’s draft or water leak is the original frame itself, a retrofit window will not solve the problem. The new unit improves the glass and sash performance but leaves the frame condition exactly as it was. Any air leaks, gap deterioration, or compromised flashing in the original frame continue to affect your home’s thermal envelope after the retrofit is complete.

Not ideal for older homes with multiple existing issues: Homes with casings, jamb extensions, or brick moulds that show cracking, rot, or deterioration are poor candidates for retrofit installation. All perimeter frame components must be structurally sound and weather-tight for a retrofit to perform correctly. An older home with multiple frame issues often needs full-frame replacement even when the visible surface looks acceptable.

Installation Process: What Actually Happens

Retrofit Window Installation (Step by Step)

1. The installer inspects the existing frame for rot, plumb, and square before ordering windows.
2. Old sash units, hardware, and weatherstripping get removed from the existing frame.
3. The new window unit is measured, shimmed, and placed into the existing opening.
4. The unit is secured with screws through the frame sides into the original wood.
5. Insulation or backer rod fills any gaps around the perimeter.
6. Sealant is applied continuously around the interior and exterior perimeter.
7. New interior trim and stops are installed to cover the frame transition.

Total time per window: 1 to 2 hours. Most homes complete in one day.

New Construction Window Installation (Step by Step)

1. The existing window and frame are fully removed down to the rough opening in the wall.
2. Exterior siding and trim around the opening are cut back to expose the wall sheathing.
3. New flashing tape and water-resistant barrier material are applied to the rough opening.
4. The new window unit is placed in the opening with the nailing fin against the sheathing.
5. The fin is nailed directly into the wall framing studs around the full perimeter.
6. Exterior flashing tape seals the fin-to-sheathing joint on all four sides.
7. Insulation fills the cavity between the window frame and the rough opening framing.
8. Exterior trim, siding, and casing are reinstalled or replaced to finish the wall.
9. Interior drywall return and trim are finished to match the existing wall.

Total time per window: 3 to 4 hours. Most homes take 3 to 5 days for a full project.

Can You Install New Construction Windows in an Existing Home?

Yes. New construction windows are not limited to newly built homes. They can be installed in an existing home during a renovation or remodel project.

The key distinction is what the installation requires. In a new build, the walls are open and the studs are exposed before siding goes on. Installing the window is straightforward because there is nothing to remove first.

In an existing home, the installer must cut back and remove the exterior siding, casing, and any trim around the opening to expose the wall studs. The old window and frame come out completely. Then the new construction window goes in exactly as it would in a fresh build, with the nailing fin secured to the exposed studs before exterior materials are reinstalled.

This additional demolition and exterior finishing work is why new construction windows cost significantly more as a standalone replacement project in an existing home. When paired with a siding replacement project, the cost premium shrinks because the exterior work is already happening anyway.

Energy Efficiency: Which Type Performs Better?

Both retrofit and new construction windows can achieve excellent energy efficiency. The determining factor is installation quality, not installation type alone.

New construction windows have a structural advantage in energy performance because they allow for complete air sealing from the rough opening outward. The nailing fin creates a base for a continuous weather barrier when properly flashed. Foam insulation can fill the entire cavity between the frame and the rough opening framing. This level of thermal isolation is not possible with retrofit installation because the original frame material stays in the wall.

Retrofit windows can match new construction thermal performance in homes where the original frame is in excellent condition and is well-insulated already. A properly installed retrofit window in a sound frame can reduce energy costs by 15 to 25% compared to single-pane or compromised windows. The glass technology matters most: low-E coatings, argon gas fills, and warm-edge spacer systems are available in retrofit window products at the same quality level as new construction options.

The energy performance gap between the two types is most significant in older homes where the original frame insulation is minimal or degraded. In those situations, new construction installation addresses the full thermal envelope, while retrofit installation only improves the glass and sash portion of it.

Performance Comparison: Real-World Results

Energy Efficiency: New construction windows typically achieve better energy performance because they allow for complete air sealing and insulation. The continuous thermal barrier created by proper new construction installation often results in measurably lower heating and cooling costs.

Retrofit windows can achieve good energy efficiency when installed in quality existing frames, but they’re limited by the original window’s thermal performance characteristics. Air leaks around the original frame remain problematic.

Water Protection: New construction installation with proper flashing provides superior water protection. The nailing fin, when correctly flashed, creates multiple barriers against water infiltration.

Retrofit installation relies on the existing frame’s water resistance. If the original flashing or frame seal has deteriorated, retrofit windows won’t solve water infiltration problems.

Structural Integration: New construction windows become part of your home’s structural system through the nailing fin attachment. This creates better long-term stability and reduces the risk of frame movement or settling issues.

Retrofit windows depend on the existing frame’s structural integrity. Over time, this can lead to operational problems if the original frame shifts or settles.

Cost Comparison: New Construction vs Retrofit Windows

Do New Windows Increase Home Value?

Yes, window replacement increases home value in most markets. The type of installation affects how much.

New construction windows tend to offer stronger resale appeal because buyers and home inspectors can verify that the entire window system, including the frame, flashing, and structural connection, was replaced. A complete system replacement reads as a more thorough improvement than an insert. In competitive real estate markets, this distinction can affect buyer perception and appraisal results.

Retrofit windows still improve home value through better energy efficiency ratings, improved curb appeal, and the removal of obviously worn or damaged windows. For sellers who need to update windows before listing without a large capital outlay, retrofit replacement is a cost-effective way to improve the home’s appeal and pass an inspection without a full structural window project.

Energy-efficient windows certified by ENERGY STAR add value in either installation type. In Middle Georgia’s mixed climate with hot summers and cool winters, windows with low-E coatings and argon gas fills reduce both cooling and heating loads, which translates directly to lower monthly utility costs that buyers factor into purchase decisions.

Pros and Cons of Retrofit Windows

Pros:

• Lower total installed cost (30 to 50% less than new construction on average)
• Minimal disruption to your home during installation
• Installed primarily from inside, no exterior access required
• Preserves existing exterior trim, siding, and architectural details
• Faster installation timeline (one to two days for most homes)
• Reduces construction waste compared to full-frame replacement
• Wide range of styles, glass types, and frame materials available
• Excellent energy efficiency when installed in sound existing frames

Cons:

• Slightly reduced glass surface area because the unit sits inside the existing frame
• Cannot fix problems that originate in the old frame itself
• Performance depends entirely on the condition of the original frame
• Not suitable for homes with rotted, warped, or water-damaged frames
• Cannot change window size or location
• Improper installation causes misaligned sashes and water infiltration
• Not ideal for older homes with deteriorated casings or jamb extensions

Pros and Cons of New Construction Windows

Pros:

• Complete frame replacement addresses all underlying structural issues
• Superior air sealing and insulation around the full window perimeter
• Allows size changes, style changes, and new window locations
• Better long-term structural integration with the home
• Ideal when paired with siding replacement projects
• Greater appeal to buyers and appraisers in resale situations
• Addresses frame rot, water damage, and insulation deficiencies permanently

Cons:

• Higher total installed cost (50 to 100% more than retrofit on average)
• Requires exterior work including siding removal, flashing, and trim replacement
• Longer installation timeline (three to five days for most homes)
• More disruption to daily routine and home access
• Exterior materials may not match perfectly after reinstallation on older homes
• Overkill for homes with structurally sound existing frames

The Environmental Angle: Which Option Is More Sustainable?

Retrofit windows generate less construction waste than new construction replacement. Because the original frame stays in the wall, there is no demolition of wood framing, no siding removal and disposal, and no trim material that goes to the landfill. For homeowners who want to minimize the environmental impact of their renovation, retrofit installation is the greener choice.

Modern retrofit window products are built with low-E glass, insulated multi-chamber vinyl frames, and warm-edge spacer technology that reduces heat transfer at the glass edge. These features lower the home’s heating and cooling energy use over the window’s lifespan, reducing the carbon footprint of the home beyond just the installation event itself.

New construction windows are not inherently less sustainable, but the full-frame replacement process generates more waste and requires more raw materials. When frame replacement is necessary, the long-term energy performance of the new installation often offsets the environmental cost of the construction work over the window’s expected lifespan.

Quality Markers to Look for in Either Type

Regardless of whether you choose retrofit or new construction installation, these quality factors separate high-performing windows from builder-grade products that fail early.

The NFRC Label

The National Fenestration Rating Council (NFRC) label is the only independent energy performance rating system for windows in the United States. Look for NFRC-certified products and compare U-factor (heat transfer) and Solar Heat Gain Coefficient (SHGC) ratings between options. In Middle Georgia’s climate, a lower U-factor reduces winter heat loss and a moderate SHGC rating balances summer solar gain against winter passive solar benefit.

Heat-Welded Frame Joints

High-quality windows have heat-welded frame corners where the vinyl or fiberglass is fused together under heat and pressure. Lower-quality windows use mechanical fasteners, screws, or adhesive brackets to join the corners. Heat-welded joints are significantly more airtight, more durable, and more water-resistant over the window’s lifespan.

Stainless Steel Hardware

All locking mechanisms, hinges, operators, and balance systems should use stainless steel or corrosion-resistant components. Painted zinc or cheap plated hardware corrodes in humid climates and fails within a few years. Middle Georgia’s humidity makes this especially important.

Color-Matched Components

All visible frame components, including the sash, frame, screen frame, and hardware, should match in color and finish. Mismatched colors are a sign of mixed-quality components and indicate that the window was assembled with lower-grade parts in some areas.

Multi-Chamber Frame Construction

High-quality vinyl frames have multiple internal air chambers that slow heat transfer through the frame itself. Single-chamber frames conduct heat and cold more readily. For both retrofit and new construction windows, look for frames with at least three chambers in the main frame members.

Common Mistakes That Cost Thousands

Choosing Retrofit for Damaged Frames: Installing retrofit windows in frames with rot, air leaks, or structural problems doesn’t solve the underlying issues. Homeowners end up spending money twice – once for retrofit windows that don’t perform well, then again for proper new construction replacement.

Selecting New Construction When Retrofit Would Work: Some contractors push new construction replacement because it’s more profitable, even when retrofit would adequately address the homeowner’s needs. This unnecessary expense can add thousands to your project cost.

Ignoring Exterior Integration: New construction windows require proper exterior finishing work. Skimping on flashing, sealant, or trim work compromises the entire installation and can lead to expensive water damage.

Misunderstanding Warranty Coverage: Window warranties often depend on proper installation type. Installing new construction windows without nailing fins, or retrofitting windows in inappropriate applications, can void manufacturer warranties.

Climate Considerations for Your Decision

Your local climate affects which option provides better long-term performance.

Cold Climate Performance: In areas with significant heating demands, the superior air sealing possible with new construction installation often provides measurably better comfort and energy savings. The thermal bridging reduction achieved through comprehensive installation justifies the higher cost.

Hot Climate Considerations: In cooling-dominated climates, both options can perform well if properly installed. The decision often comes down to existing frame condition and budget considerations rather than energy performance differences.

Moisture Management: High-humidity climates require excellent water protection. New construction installation with proper flashing typically provides better long-term moisture management, especially important in areas prone to wind-driven rain.

Quality Factors That Matter Regardless of Type

Frame Materials: Both new construction and retrofit windows benefit from quality frame materials. Vinyl frames with multiple chambers provide good insulation. Fiberglass frames offer superior durability and dimensional stability. Wood frames provide excellent insulation but require more maintenance.

Glass Technology: Low-E coatings, argon gas fills, and proper spacer systems improve performance in both window types. Don’t sacrifice glass quality to save money on frame choice.

Hardware Quality: Both window types depend on quality hardware for smooth operation and long-term reliability. Cheap hardware fails quickly and compromises security and energy efficiency.

Installation Quality: Even the best windows perform poorly with inadequate installation. Proper air sealing, insulation, and water management are crucial regardless of window type.

Professional Assessment: When to Get Expert Help

Structural Evaluation: If you’re unsure about existing frame conditions or structural requirements, professional assessment prevents costly mistakes. Experienced contractors can identify issues that aren’t obvious to homeowners.

Energy Modeling: For homes with high energy bills, professional energy assessment can quantify the benefits of different window options. This analysis helps justify higher upfront costs when energy savings support the investment.

Code Compliance: Local building codes may require specific installation methods or performance standards. Professional installers understand these requirements and ensure compliance.

The Bottom Line: Which Is Actually Better?

Neither new construction nor retrofit windows are universally “better” – the right choice depends on your specific situation, goals, and budget.

Choose new construction windows when you want maximum long-term performance, have frame problems to address, plan other exterior improvements, or prioritize energy efficiency above cost considerations.

Choose retrofit windows when your existing frames are in good condition, you need to minimize disruption and cost, or you want to preserve original architectural elements.

The most important factor isn’t which type you choose, but matching the right solution to your specific needs and ensuring quality installation regardless of the approach.

At The Window Source of Middle Georgia, we’ve seen the results of both approaches in Middle Georgia homes for decades. The homeowners who are happiest long-term are those who made informed decisions based on their actual needs rather than price alone. We help our customers understand exactly what each option provides and make recommendations based on their specific situation and goals.

Remember that windows are a long-term investment. Whether you choose new construction or retrofit, focus on quality products and professional installation. Both approaches can provide excellent results when properly matched to your home’s needs and installed by experienced professionals who understand the technical requirements for long-term performance. 

Frequently Asked Questions

What is a retrofit window?

A retrofit window is a new window unit designed to fit inside an existing window frame. The original frame stays in the wall. Only the glass, sash, and hardware get replaced. This type of installation is also called a replacement window, pocket installation, or insert window depending on the manufacturer and region.

Are retrofit windows the same as replacement windows?

Yes. Retrofit windows and replacement windows are the same product installed the same way. The terms are used interchangeably across the industry. Different brands and regions use different terminology, but both describe a window unit that installs inside an existing frame without removing the original frame from the wall.

Do you install retrofit windows from the inside or outside?

Retrofit windows are installed primarily from inside the home. The installer removes the old sash from inside, places the new unit into the existing opening, and secures it from the interior side. This is why retrofit installation causes minimal exterior disruption.

Can you put new construction windows in an existing home?

Yes. New construction windows can be installed in an existing home during a remodel. The installer must remove exterior siding and trim to expose the wall studs, remove the old window and frame completely, and then install the new window with its nailing fin secured to the exposed framing. This is more expensive as a standalone project but becomes more cost-effective when paired with siding replacement.

What are the main problems with retrofit windows?

The main problems are: reduced glass surface area because the unit sits inside the existing frame; inability to fix leaks or drafts that come from the original frame itself; potential for water infiltration if the wrong sealant is used; and misaligned sashes if the unit is not properly shimmed during installation.

Which window installation causes least disruption?

Retrofit window installation causes the least disruption. Work happens from inside the home, with no exterior siding removal, no structural modification, and no landscaping impact. Most homes finish in a single day.

Are new construction windows better than retrofit windows?

Neither is universally better. New construction windows are better when your frames are damaged, when you need to change window size, or when you are already doing exterior work. Retrofit windows are better when your frames are sound, your budget is a priority, and you want minimal disruption. The right choice depends entirely on your specific home’s condition and your project goals.

How much do retrofit windows cost compared to new construction?

Retrofit windows typically cost $300 to $700 per window installed. New construction windows typically cost $700 to $1,400 per window installed when exterior work is included. The cost gap shrinks significantly when new construction windows are installed alongside a siding replacement project.

What is a block frame window?

A block frame window is a type of retrofit window that uses the existing wood frame as its mounting surface with no exterior flange. It works best in homes with vinyl or wood siding where the existing frame is in good condition. It is one of three main retrofit window types, alongside flush fin (Z-bar) windows and standard pocket or insert windows.