Aluminum Single Hung Windows: Cost, Specs & Single vs. Double Hung

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Aluminum Single Hung Windows: What Makes Them Different?

An aluminum single hung window has two visible sash sections, but only the bottom sash is operable. The lower sash slides vertically while the upper sash remains fixed.

That simpler configuration can make a single               hung window attractive when the project needs:

• Lower initial cost
• A conventional vertical-window appearance
• Bottom-only ventilation
• Fewer operable components
• A straightforward replacement configuration

The trade-off is equally clear: you cannot ventilate through the upper portion of the opening, and a fixed upper sash may be harder to clean from inside depending on the product design.

For US projects, however, the decision should not be based on sash operation alone. A good specification also considers sash weight, balance hardware, glazing, thermal performance, air leakage, water penetration, structural performance and applicable NAFS classification.

The key principle is:

Choose a single hung window because its tested performance and operating requirements fit the project—not simply because it costs less than a double hung.

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Quick Summary: Single Hung at a Glance

Question	Single Hung Answer
What moves?	Bottom sash
What stays fixed?	Upper sash
Main advantage	Simpler operation and lower hardware complexity
Main limitation	No upper-sash ventilation
Upper-sash cleaning	Usually requires exterior access unless the product is specifically designed to tilt
Best for	Standard residential openings, replacement projects and budget-conscious applications
Key technical checks	Balance capacity, glazing weight, air/water performance and NAFS rating

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Why Choose a Single Hung Window?

The main advantage of a single hung system is simplicity.

Only one sash moves, so the balance system, operating hardware and moving interface are concentrated on the lower sash. That can make the product easier to specify and, in many applications, less expensive than a comparable double hung.

This does not mean every single hung window is automatically better sealed or more durable.

A fixed upper sash removes one operable interface, but actual air leakage depends on the seal design, meeting rail, fabrication and tested product configuration. For procurement, the correct approach is to compare the documented air-performance result rather than assume that fewer moving parts guarantee a lower leakage rate.

Single hung windows make particular sense when the upper part of the opening does not need to operate.

Common applications include:

• Bedrooms
• Living areas
• Ground-floor renovations
• Multifamily housing
• Standard replacement openings
• Projects where bottom-only ventilation is sufficient

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What Are You Giving Up Compared With Double Hung?

The single hung design is economical because it does less.

No Upper-Sash Ventilation

A double hung can open both the lower and upper sash. This allows the occupant to control the inlet and outlet areas of the opening.

With a single hung, the upper sash remains fixed.

That matters in rooms where ventilation strategy depends on opening the upper part of the window.

More Limited Cleaning Access

Some modern single hung products provide tilt-in or removable sash features, but this is not universal.

In a conventional configuration, the fixed upper sash requires exterior access for cleaning.

That is usually straightforward on a ground floor but becomes more relevant on upper floors and multifamily buildings.

Less Flexible Ventilation Control

A double hung can open from:

• Bottom
• Top
• Both simultaneously

A single hung provides only the lower opening.

The correct choice therefore depends on whether additional ventilation control justifies the higher system complexity and cost.

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How an Aluminum Single Hung Window Works

Fixed Upper Sash

The upper section is retained within the frame and does not move.

Its fixed configuration can simplify the frame and reduce the number of operable interfaces that must be maintained.

Moving Lower Sash

The lower sash moves vertically in the jamb channels.

Depending on the system, it may use:

• Block-and-tackle balances
• Constant-force balances
• Spiral balances
• Other manufacturer-specific counterbalance systems

The Balance System

The balance offsets the weight of the moving sash.

This is one of the most important components to specify because the balance must be compatible with the actual sash weight.

That weight changes with:

• Window size
• Glass thickness
• Double or triple glazing
• Laminated glass
• Acoustic glass
• Grid or decorative components

A balance that is too weak may allow the sash to drop or become difficult to operate.

A balance that is incorrectly matched can also increase operating force and accelerate hardware wear.

Procurement rule:

Specify the balance against actual sash weight and the manufacturer’s tested configuration—not nominal window dimensions alone.

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Meeting Rail and Weather Sealing

The meeting rail is where the upper and lower sash sections meet.

This area needs coordinated:

• Weatherstripping
• Interlocks
• Latches
• Drainage
• Sash alignment

Because the lower sash moves against the fixed upper section, the meeting rail must maintain alignment during repeated operation.

For a US project, request the tested air and water performance for the complete window rather than assuming that the meeting rail geometry alone guarantees performance.

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Thermal Performance: U-Factor Depends on the Complete Window

An aluminum frame can be thermally improved with a thermal break, but a thermal-break label by itself does not guarantee a specific U-factor.

Whole-window energy performance depends on:

• Frame geometry
• Thermal-break design
• Glass
• Low-E coating
• Gas fill
• Spacer
• Window size
• Configuration

For US products, NFRC-certified ratings allow buyers to verify product-level U-Factor, SHGC and VT rather than relying on generic frame claims. The NFRC Certified Products Directory allows searches by these product-performance values and configuration characteristics.

Request: the NFRC rating or applicable certification for the exact window and glazing configuration being purchased.

Do not use a generic “U-factor around 1.8 W/m²K” as a universal specification for all aluminum single hung windows.

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US Performance Standards: NAFS, Air, Water and Structural Testing

For US projects, do not evaluate a window by material alone.

The current North American Fenestration Standard is AAMA/WDMA/CSA 101/I.S.2/A440-26 (NAFS-26), published in June 2026. It is a performance-based, material-neutral specification covering windows, doors and skylights and is used as a basis for product certification in North America.

For a project specification, verify the applicable:

• NAFS product classification
• Design pressure
• Air-leakage performance
• Water-penetration performance
• Structural performance
• Product size and tested configuration

The exact requirements depend on the building code, project location, exposure and window configuration.

ASTM test methods may be used within the applicable fenestration testing and certification framework. For example, ASTM E331 evaluates water penetration under a specified static pressure difference, but the resulting performance is tied to the tested assembly and test conditions.

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What Does an Aluminum Single Hung Window Cost?

Cost depends heavily on:

• Window size
• Frame system
• Thermal-break construction
• Glass package
• Finish
• Hardware
• Certification
• Replacement or new construction
• Installation conditions

As a 2026 consumer-market benchmark, HomeAdvisor lists single-hung windows at about $100–$400 for the window alone, while aluminum windows overall are listed around $75–$400 per unit. HomeAdvisor also reports labor costs commonly ranging from approximately $100–$400 per window, depending on the project. These figures are market reference ranges rather than a quotation for a custom architectural aluminum system.

The same source shows that double-hung windows generally cost more because both sashes operate and the system requires additional hardware.

For project procurement, therefore, compare total specification, not just the window-unit price.

A lower single hung quotation may reflect:

• Non-thermal framing
• Basic glazing
• Lower-cost finish
• Simpler hardware
• Reduced testing documentation
• Standard rather than custom dimensions

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Single Hung vs Double Hung Windows

Factor	Single Hung	Double Hung
Moving sashes	Bottom only	Upper + lower
Ventilation	Lower opening	Upper, lower or both
Hardware complexity	Lower	Higher
Initial cost	Usually lower	Usually higher
Upper-sash cleaning	Usually exterior access	Many designs allow interior cleaning
Ventilation control	Basic	More flexible
Maintenance	Fewer operable components	More operating components
Best use	Cost-conscious standard openings	Ventilation flexibility and upper-floor cleaning

There is no universal winner.

Choose a single hung when the upper opening does not need to operate and project cost or simplicity is important.

Choose a double hung when upper-sash ventilation or easier cleaning of both sash faces provides enough value to justify the added system complexity.

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Aluminum Single Hung Window Sizing

There is no universal maximum size for every aluminum single hung system.

The practical limit depends on:

• Frame dimensions
• Sash dimensions
• Glass weight
• Balance capacity
• Wind pressure
• Profile reinforcement
• Hardware
• Tested configuration
• Installation conditions

For larger windows, the lower sash becomes heavier, increasing the load on the balance and jamb hardware.

Therefore, specify:

1. Rough opening width
2. Rough opening height
3. Frame dimensions
4. Glass make-up
5. Sash weight
6. Project location
7. Design pressure
8. Required NAFS classification

For replacement projects, the existing opening should also be checked for level, plumb, depth and drainage before the new frame is finalized.

See our aluminum replacement windows guide for additional retrofit considerations.

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Aluminum Single Hung Window Procurement Checklist

Before approving a supplier, request:

• Section drawing
• Aluminum alloy and temper
• Profile wall thickness
• Thermal-break details
• Sash weight
• Balance type and capacity
• Glass build-up
• Whole-window U-Factor
• SHGC where applicable
• Air-leakage performance
• Water-penetration performance
• NAFS classification
• Design pressure
• Finish specification
• Hardware specification
• Installation and drainage details
• Applicable test reports/certification

The key question is:

Does the documentation describe the same size, glazing, frame and hardware configuration that you are actually ordering?

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Frequently Asked Questions

What is an aluminum single hung window?

An aluminum single hung window has one operable sash—the bottom sash slides vertically while the upper sash remains fixed. It offers conventional vertical-window proportions with less operating hardware than a double hung system.

Is a single hung window cheaper than a double hung?

Generally, yes. A single hung has only one operating sash and therefore less operating hardware. Current consumer cost guides also show single-hung windows generally priced below comparable double-hung windows, although custom aluminum specifications can vary substantially.

Are single hung windows more energy efficient than double hung windows?

Not automatically. A single hung has fewer operable interfaces, but actual air leakage and thermal performance depend on the complete tested window system. Compare whole-window U-Factor and documented air-performance results instead of assuming one style is inherently more efficient.

Can a single hung window have a thermal break?

Yes. A thermally broken aluminum single hung can separate the interior and exterior frame sections with a low-conductivity barrier. The resulting U-Factor depends on the complete frame, glazing, spacer and window configuration.

Why won’t my single hung window stay up?

The balance system is a common cause. If the balance is worn, damaged or incorrectly matched to the sash weight, the lower sash may become difficult to operate or fail to remain in position.

Can the upper sash of a single hung window tilt in?

Some products are designed with removable or tilting upper-sash features, but this is not universal. Verify the actual product design before specifying a single hung window where interior upper-sash cleaning is required.

What NAFS rating does an aluminum single hung window need?

There is no single NAFS rating suitable for every project. The required classification depends on building type, location, exposure, design pressure and applicable code requirements. The 2026 NAFS edition is AAMA/WDMA/CSA 101/I.S.2/A440-26.

Are aluminum single hung windows good for replacement projects?

Yes, particularly when the existing opening and operating requirements are compatible with a vertically sliding lower sash. Before ordering, verify the rough opening, frame depth, drainage, glass specification, balance capacity and required performance.

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Bottom Line

An aluminum single hung window is a sensible choice when the project needs a conventional vertical window without paying for two operable sashes.

Its main advantages are simpler operation, lower hardware complexity and generally lower initial cost. Its main limitations are bottom-only ventilation and more limited upper-sash cleaning access.

For US projects, make the decision based on the complete specification:

sash weight + balance capacity + glazing + whole-window U-Factor + air/water performance + NAFS classification + design pressure + finish + installation.

For a project-specific quotation, send Starveil your rough opening dimensions, glass requirements, project location and required performance criteria. We can review the configuration, balance requirements, glazing and window specification before production.

Request an Aluminum Single Hung Window Specification Review →