TL;DR: Old Castle Glass Company was a large glass manufacturer that has gone through major corporate changes. If you are searching for their products or warranties in South Florida, you need to understand what brand now carries that business forward, how it affects impact-window shopping, and what really determines whether a window protects your home and lowers your insurance bill.
What Happened to Old Castle Glass Company
Old Castle Glass Company operated for decades as one of North America's largest glass fabricators and distributors. The company supplied flat glass, insulated glass units (IGUs, meaning two panes sealed together with an air or gas gap), and specialty architectural glass to window manufacturers across the country.
In what was publicly reported as a 2016 transaction, CRH plc, the Irish building-materials conglomerate that owned Oldcastle, sold the glass division to Vitro S.A.B. de C.V., a Mexican glass manufacturer, which rebranded the operation as Vitro Architectural Glass. Readers researching warranty chain-of-title should verify the transaction details directly with Vitro, as primary documentation may differ from published reports. The Oldcastle and Old Castle Glass Company names you see in search results today largely refer to that legacy operation. Vitro now holds the manufacturing footprint and the product lines that were associated with Oldcastle glass. Vitro has generally stated it honors Oldcastle glass warranty obligations, but homeowners should verify directly with Vitro for their specific product.
This matters to Florida homeowners because Oldcastle glass was used as a component inside finished windows and doors made by many brands. The glass itself is not the same thing as a complete, code-approved impact window. Understanding that distinction saves you time and money.
Why It Matters for South Florida Impact Window Buyers
Glass is a component, not a finished product
When you buy hurricane impact windows in Palm Beach or Broward County, you are buying a complete assembly: the frame (aluminum or vinyl), the glazing (the glass unit), the interlayer (a film, usually PVB or SGP, that holds shards together on impact), and the hardware. The glass inside that assembly may have been sourced from a large manufacturer like Vitro/Old Castle Glass Company, but the Florida Product Approval belongs to the window manufacturer, not the glass supplier.
Florida Product Approval (NOA, or Notice of Acceptance in Miami-Dade) certifies the entire window system as tested. Broward and Palm Beach counties require windows to carry valid product approvals before installation. Knowing who made the raw glass tells you almost nothing about whether the finished window meets current Florida Building Code requirements.
Insurance discounts hinge on the whole system, not the glass brand
Homeowners in Palm Beach and Broward counties can qualify for significant windstorm premium reductions by installing impact-rated openings. Under Florida's Uniform Mitigation Verification Inspection form (OIR-B1-1802), the inspector looks at the opening protection type, the product approval number, and the installation method. No line on that form asks who manufactured the raw glass.
The discount range varies by insurer and home. Depending on the carrier, policy, and inspection result, fully protected homes (all openings rated) may qualify for windstorm premium reductions compared to homes with no opening protection, but the amount is not guaranteed and will differ based on your specific insurer, coverage, and inspection outcome. That is where the real financial return on impact windows comes from, and it depends on a properly installed, code-approved system, not on a specific glass brand name.
Energy performance is about the whole IGU, not the brand alone
South Florida buyers often want energy efficient windows to cut cooling costs. The metrics that matter are the Solar Heat Gain Coefficient (SHGC, how much solar energy passes through) and U-factor (how well the window insulates). Florida's Energy Code sets SHGC requirements for residential applications in climate zones 1 and 2, which covers all of Palm Beach and Broward; however, the specific maximum SHGC can vary by code cycle, fenestration area ratio, and other factors. Verify the current adopted code requirements with your contractor or the Florida Building Commission before purchasing.
Vitro (the successor to Old Castle Glass Company) does manufacture low-emissivity coated glass (low-e, a thin metallic coating that reflects heat) that can meet or exceed those targets. But any reputable impact-window manufacturer sources glass that meets Florida's energy code as a baseline. The brand of glass is less important than confirming the window's SHGC and U-factor on the NFRC label (a standardized energy rating sticker).
Replacing older single-pane or clear-glass windows with code-compliant impact IGUs can reduce cooling energy use for the glazed area by a meaningful amount. The U.S. Department of Energy notes that heat gain and loss through windows can account for a significant share of home heating and cooling energy use, and that energy-efficient windows can reduce that load, though actual savings depend on window area, orientation, your current HVAC system, and other home-specific factors. Those savings are not a guarantee for your specific home.
What about existing Oldcastle glass warranties?
If you already have windows in your home that contain Oldcastle-branded glass, Vitro has generally stated it honors Oldcastle glass warranty obligations, but homeowners should verify directly with Vitro Architectural Glass for their specific product. For seal failures (fogging between panes), coating defects, or breakage covered under a manufacturer warranty, your point of contact is now Vitro Architectural Glass. The finished-window manufacturer's warranty for the frame and hardware remains with that manufacturer separately.
If you are buying a resale home in West Palm Beach, Boca Raton, or Fort Lauderdale and the listing mentions Oldcastle glass windows, treat it the same as any other window: verify the Florida Product Approval number, check the installation date against the current code cycle, and confirm whether any warranty is transferable.
Ready for hurricane-rated impact windows? Request a free estimate
What We Don't Know Yet
A few things remain genuinely uncertain for South Florida buyers researching Old Castle Glass Company:
Long-term warranty administration. Large corporate rebrands sometimes create gaps in warranty service. Vitro has generally honored Oldcastle obligations, but processes can change. If you have an active claim or anticipate needing one, document your product information now.
Product line continuity. Not every glass product sold under the Oldcastle name has a direct Vitro equivalent. Specialty glass types or regional product lines may have been discontinued. If a contractor quotes you a specific Oldcastle product by name, confirm it is still available under the Vitro catalog.
Future corporate changes. CRH and Vitro are both large companies with active acquisition histories. The brand name on the glass in your window could change again. This reinforces why the finished-window manufacturer's approval and your installer's workmanship warranty matter more than the glass supplier's name.
What to Do About It
If you are replacing windows or doors in Palm Beach or Broward County, here is a practical checklist based on what actually drives value and savings:
1. Focus on Florida Product Approval, not glass brand. Ask any contractor for the product approval number (NOA or FL number) before signing anything. You can verify it at the Florida Building Commission's product approval search tool or at the Miami-Dade NOA database. This confirms the whole system is code-compliant.
2. Get the mitigation inspection scheduled. After installation, hire a licensed wind mitigation inspector to complete form OIR-B1-1802 and submit it to your insurer. That form is what triggers your windstorm discount. Do not skip this step. The discount often pays back a meaningful share of the installation cost over time.
3. Check your SHGC and U-factor. For window replacement in South Florida, confirm your window's SHGC meets the current Florida Energy Code requirement for your application , verify the applicable maximum with your contractor or the Florida Building Commission, as requirements can vary by code cycle and fenestration ratio. Lower SHGC is better for cooling. This is the single biggest energy-performance variable you control at purchase.
4. Verify the installer's license and permits. In Florida, window and door replacement requires a permit in virtually every municipality. A licensed contractor pulls the permit, which triggers a building inspection that protects you legally. Window Guys of Florida is licensed and pulls permits on applicable jobs in Palm Beach and Broward counties.
5. Ask about financing and utility programs. Florida Power and Light and other utilities have periodically offered rebate programs for energy-efficient window upgrades. Check your utility's current website for active offers. For larger projects, many homeowners use PACE financing (Property Assessed Clean Energy), which attaches repayment to your property tax bill rather than requiring a credit-based loan. Rates and terms vary, so compare carefully.
6. Do not let the glass brand drive your decision. Whether the glass inside your new impact window was made by Vitro, Guardian, AGC, or another glass manufacturer, what matters is the complete window's ratings, the installer's workmanship, and the permit record. A properly installed, code-approved hurricane impact window from a reputable manufacturer protects your home and earns your insurance discount regardless of which glass plant produced the pane.
If you have impact doors to replace as well, including sliding glass doors or entry doors, the same logic applies. Each opening needs its own product approval and needs to appear on your mitigation inspection form.
Ready to get accurate numbers for your home? Request an estimate from Window Guys of Florida. We serve West Palm Beach, Boca Raton, Delray Beach, Fort Lauderdale, and surrounding communities with licensed installation experience in Palm Beach and Broward counties.
Ready for hurricane-rated impact windows?
Window Guys of Florida installs code-compliant, NOA-approved impact windows across Palm Beach and Broward. Licensed in Florida glass and glazing since 2005.
Frequently asked questions
Is Old Castle Glass Company still in business?
Old Castle Glass Company was sold to Vitro S.A.B. de C.V., a Mexican glass manufacturer, in a transaction publicly reported as closing in 2016, and was rebranded as Vitro Architectural Glass. The Old Castle Glass name is no longer used for new products, but Vitro continues to manufacture and distribute the glass lines that were previously sold under the Oldcastle brand.
Does the brand of glass inside an impact window affect Florida Product Approval?
No. Florida Product Approval, including Miami-Dade NOA, certifies the complete window assembly, not the individual glass component. The approval is held by the finished-window manufacturer and covers the frame, glass unit, interlayer, and hardware together as a tested system.
Will using Oldcastle or Vitro glass help me get a better insurance discount in South Florida?
The glass brand does not factor into your windstorm insurance discount. Discounts are based on the type of opening protection (impact-rated), the Florida Product Approval number, and verified installation on a wind mitigation inspection form. Depending on the carrier, policy, and inspection result, fully protected homes in Palm Beach and Broward counties may qualify for windstorm premium reductions, but the amount will vary and is not a guaranteed or typical outcome for every homeowner.
I have a home with Oldcastle windows. Who handles warranty claims now?
Vitro Architectural Glass has generally stated it honors the glass warranty obligations from the Oldcastle acquisition, but homeowners should verify directly with Vitro for their specific product. For frame and hardware warranties, you would still contact the finished-window manufacturer separately. Check your original documentation for product codes, which Vitro customer service can use to trace your specific glass product.
What glass specification should I prioritize when buying impact windows in South Florida?
Focus on Solar Heat Gain Coefficient (SHGC) and U-factor rather than the glass brand. Florida's energy code sets SHGC requirements for residential windows in climate zones 1 and 2, which includes all of Palm Beach and Broward counties, but the specific maximum can vary by code cycle, fenestration area ratio, and other factors , verify the current requirement with your contractor or the Florida Building Commission. Lower SHGC means less solar heat entering your home, which directly reduces cooling costs.
Do I need a permit to replace windows with impact glass in Palm Beach or Broward County?
Yes. Window and door replacement requires a building permit in virtually every municipality in both counties. A licensed contractor pulls the permit and the job receives a building inspection, which creates a legal record of the installation. Unpermitted work can create problems at resale and may affect insurance coverage.