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Reviewed by Alexander Hamilton Li, Architect & General Contractor · CSLB #1078806 · Updated July 2026
Single hung windows are the most common window type in Bay Area homes built before 1990, featuring a fixed upper sash and a movable lower sash that slides vertically for ventilation. Modern single hung replacements from Milgard and Andersen use dual-pane Low-E glass with argon gas fill, achieving U-factors as low as 0.25 — exceeding California’s Title 24 energy requirements by 15–20%.
The fixed upper sash provides better air and water infiltration resistance than double hung designs, while the simpler mechanism keeps installed cost $75–$100 lower per window. Bay Area homeowners replacing original aluminum single hung windows from the 1960s–80s typically see a 15–25% reduction in heating and cooling costs, according to the Department of Energy’s ENERGY STAR program.
We install single hung windows in vinyl, fiberglass, and wood-clad frames with tilt-in sash for easy interior cleaning — no ladder required.
A typical single hung replacement takes 45–60 minutes per window once the crew is set up. We remove the existing sash and frame, inspect the rough opening for rot or water damage, install new flashing and a sill pan, set the replacement unit, foam-seal the jambs, and finish with interior casing and exterior aluminum trim. Most Bay Area homes with 8–15 windows are completed in two days with minimal interior disruption — furniture stays in place and we protect floors with drop cloths.
Single hung windows perform reliably across Bay Area microclimates. In fog belt neighborhoods like the Sunset, Parkside, and Daly City, the fixed upper sash eliminates a potential leak point that double hung designs expose. In warmer inland areas like Walnut Creek and Pleasanton, the Low-E coating and argon fill keep solar heat gain coefficient (SHGC) below 0.25, reducing cooling loads. Choose single hung when budget matters, when you want the simplest long-term maintenance, or when replacing original single hung windows in tract homes where the profile should stay consistent with the neighborhood.
How Do Single-Hung Windows Compare to Other Styles?
| Feature | Single-Hung | Double-Hung | Slider |
|---|---|---|---|
| Cost per window installed | ~$850 | ~$950 | ~$800 |
| Ventilation | Bottom sash only | Both sashes | Half the opening |
| Maintenance | Low (tilt-in lower sash) | Low (both tilt-in) | Low (remove panel) |
| Energy efficiency (U-factor) | 0.25 | 0.27 | 0.27 |
| Exterior clearance | None | None | None |
How Much Do Single-Hung Windows Cost?
Single-hung window installation in the Bay Area costs approximately $850 per window fully installed, including the window unit, labor, interior and exterior trim, and weathersealing (Hamilton Exteriors project data, 2024–2026). Material cost accounts for roughly $325 of that total. A whole-house replacement project with 15–20 single-hung windows typically costs $12,750 to $17,000, making single-hung the most affordable vertical-opening window style. Single-hung windows from brands like Milgard and Andersen include tilt-in lower sashes for interior cleaning and dual-pane Low-E glass with a U-factor of 0.25, exceeding California Title 24 energy requirements. The U.S. Department of Energy reports that ENERGY STAR-qualified windows save homeowners $125–$465 per year on energy bills. With fewer moving parts than double-hung alternatives, single-hung windows also have lower long-term maintenance requirements and fewer potential points of air infiltration.
Single-Hung vs Double-Hung: What's the Difference?
Single-hung windows have one operable (moving) sash at the bottom and a fixed sash at the top. Double-hung windows have two operable sashes, both of which can open and tilt inward for cleaning. This distinction affects ventilation, cleaning convenience, and price. Single-hung windows cost approximately $850 installed in the Bay Area versus $950 for double-hung — a $100 per-unit savings that totals $1,500–$2,000 across a typical 15–20 window project (Hamilton Exteriors project data, 2024–2026). Single-hung windows achieve a slightly better U-factor of 0.25 compared to 0.27 for double-hung, because the fixed upper sash has fewer air-infiltration pathways. However, double-hung windows offer convection ventilation (opening both top and bottom) and easier cleaning of the upper sash from inside the home. For second-story or hard-to-reach windows, double-hung's tilt-in upper sash is a meaningful practical advantage.
What Homeowners Say About Our Work
Real reviews from verified Northern California homeowners.
deborah maxey
in the last week
Great job and very professional the 1st photo is before and the other 2 is upon completion of work.
Eric W.
via Yelp
Hamilton Exteriors did an amazing job on my roof. The team was professional, and the quality of work was top-notch. Highly recommend!
Robert H.
via Angi
From the very first consultation, we knew we'd made the right choice. The team was knowledgeable and genuinely listened to our concerns about energy efficiency and design. We've already noticed a drop in our energy bills.
Laura G.
via Nextdoor
Hamilton Exteriors repaired extensive dry rot damage on our home's exterior. Their attention to detail and commitment to quality were evident throughout the project. Our home looks better than ever.
Frequently Asked Questions
Didn't find the answer to your question? Call Now (650) 977-3351
What areas do you serve?
We serve Northern California across three regions: the San Francisco Bay Area (six counties from Alameda to Santa Clara), Greater Sacramento (Sacramento out to Roseville, Folsom, and Davis), and the Central Valley (Stockton to Modesto). Our crews are based in Castro Valley. We handle permits and know the building codes for each jurisdiction, which matters because requirements and fees vary significantly between cities.
How does billing and financing work?
We offer $0-down financing with approved credit, 12-month same-as-cash plans, and extended terms up to 15 years for larger projects. You only pay for completed, inspected work — we never ask for full payment before the job is done. Your project manager will walk you through every option during your estimate appointment. We also accept checks, ACH, and all major credit cards.
Are you licensed and insured?
Yes. CSLB License #1078806 — verify it anytime at cslb.ca.gov. We carry $2M general liability, full workers’ comp, and are bonded per California law. We hold GAF Master Elite, Owens Corning Preferred, CertainTeed ShingleMaster, and James Hardie Elite Preferred certifications — each requires annual training and quality audits to maintain. We’re happy to provide proof of insurance before any work begins.
Do I need a permit for my exterior project?
Most exterior projects in Northern California require a building permit. Fees vary by city — Oakland runs $200–$600, Peninsula cities often more. We handle the entire permit process: application, plan submission, and scheduling inspections. Permit fees appear as a separate line item in your estimate so you’ll see every cost upfront. For homes in WUI fire zones (Berkeley Hills, Oakland Hills, parts of Marin), we ensure full compliance with local fire-rated material requirements.
What's the difference between single hung and double hung?
Single hung windows have one fixed sash (top) and one operable sash (bottom). Double hung windows have two independently operable sashes. Single hung costs less, seals tighter, and is simpler to maintain — ideal for most Bay Area applications.
How much do single hung replacement windows cost?
Single hung replacement windows cost $600–$1,200 per window installed in the Bay Area, depending on frame material (vinyl, fiberglass, or wood-clad) and glass options. Vinyl is most affordable; wood-clad matches historic home aesthetics.
How long does single hung window installation take?
Each window takes 45–60 minutes to install. A full-home replacement of 10–15 windows is typically completed in 1–2 days. We handle removal, rough opening inspection, flashing, foam-sealing, and interior/exterior trim — no subcontractors.
Do single hung windows meet California Title 24 energy requirements?
Yes. Our Milgard and Andersen single hung units with dual-pane Low-E glass and argon fill achieve U-factors of 0.25 and SHGC values below 0.25, exceeding Title 24 prescriptive requirements for all Bay Area climate zones (CZ 3, 4, and 12).
Should I choose single hung or casement windows for my Bay Area home?
Single hung costs $75–$100 less per window and suits traditional home styles. Casement windows seal tighter (U-factor 0.22 vs. 0.25) and capture more airflow but require exterior clearance. For fog belt homes prioritizing moisture resistance, casement edges ahead. For budget-conscious whole-home replacements, single hung delivers the best value.
Get Your Single Hung Windows Estimate
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21634 Redwood Rd Unit F, Castro Valley, CA 94546
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