Single-Hung vs Double Hung Hurricane Windows for Florida Homes

Single-hung and double hung hurricane windows share the same basic frame, but differ in how many sashes are operable. In a single-hung unit, the top sash is permanently fixed to the frame, and only the bottom sash travels vertically. In a double-hung unit, both the upper and lower sashes slide independently along separate tracks. PGT notes that standard double-hung windows in a typical bedroom measure 2 to 3 feet wide and 4 to 6 feet tall, and can be installed in pairs or triples for larger openings. Because the upper sash in a double-hung moves, it adds a second weatherseal, a second set of balance springs, and slightly more frame hardware, all of which contribute to the modest price premium PGT mentions. Understanding these mechanical differences is the first step toward choosing the right style for each opening in your home. For a broader look at all operating styles available in impact-rated products, see our guide to the types of impact windows on the market today.

2 Miami-Dade NOAs (Notice of Acceptances) covering these exact models are currently active, which matters in HVHZ counties like Miami-Dade and Broward. The PGT WinGuard Vinyl SH5500 single-hung carries NOA 25-0520.01, rated for large and small missile impact, expiring July 30, 2030. Its maximum O/X size reaches 52-1/8 × 84 inches, with a custom sash option up to 54 × 91-3/4 inches. The embedded sash tilts in for interior cleaning, and an optional window opening control device certified to ASTM F2090 is available. The PGT WinGuard Vinyl DH5560 double-hung holds NOA 25-0710.04, also large and small missile rated, expiring September 17, 2030. Its equal-lite X/X maximum size is 54 × 84 inches, both sashes tilt in for cleaning. Both styles are available in Florida-approved impact lines, such as PGT's SH5500 single hung and DH5560 double hung. To learn more about the full PGT product lineup we carry, visit our PGT Custom Windows & Doors brand page.

Energy performance is where the 2 operating styles diverge most clearly on paper. The DH5560 product sheet lists 2 laminated insulating glass (LIG) options using 7/8-inch laminated glass: Energy Shield at U-value 0.35 / SHGC 0.29, and SolarControl LowE2 at U-value 0.35 / SHGC 0.19. PGT does not publish equivalent glass-performance tables for the SH5500 in the same product sheet format, so a direct numerical comparison between the two models is not possible from available data. What PGT does state broadly is that single-hung windows are 'often more energy-efficient', attributed to the simpler weatherseal path around one fixed sash. South Florida homeowners aiming to reduce solar heat gain (SHGC) in west-facing rooms should ask their installer to confirm which glass package is available for the specific size ordered. The Florida Building Code sets minimum fenestration (window and door energy) requirements that all replacement windows must meet, regardless of operating style.

Beyond PGT, South Florida homeowners have other approved single-hung and double hung hurricane windows to choose from. Eco Window Systems is based in Medley, FL. The company holds Florida Product Approval FL47213 for its Eco-Novo Series 175 single-hung window. That approval was evaluated December 19, 2024. It covers a maximum load of +70/-70 psf. It also covers large and small missile impact. The window complies with the 2023 Florida Building Code inside and outside the HVHZ. Testing includes TAS 201/202/203, ASTM E283 (air), E331 (water), and F588 (forced entry). Our detailed Eco Novo impact windows review covers that product in depth. Custom Window Systems (CWS) also offers impact-rated single-hung windows under its Hurricane Guard lineup. Those are available in vinyl and aluminum. For a head-to-head look at frame materials, read our vinyl vs aluminum windows guide. It explains the trade-offs in Florida's salt-air climate. Always verify that the specific model ordered carries a current Florida Product Approval or Miami-Dade NOA. Do this before your permit is submitted. You can search active contractor licenses and approvals through the Florida DBPR contractor lookup.

Florida Residential Code R310.2 sets 4 minimums for emergency escape and rescue openings: a net clear opening of at least 5.7 square feet (5 square feet at grade floor), a net clear height of at least 24 inches, a net clear width of at least 20 inches, and a bottom of clear opening no more than 44 inches above the finished floor. All 4 conditions must be met simultaneously from normal operation, no tools, no keys, no special knowledge required under R310.1.1. When replacing an existing egress window, Florida Existing Building Code 702.5 gives contractors a practical path: the replacement is exempt from hitting the R310.2 minimums if it is the manufacturer's largest standard size that fits the existing rough opening and it matches the original operating style or uses one with equal or greater opening area. This means installing a double hung hurricane window to replace an existing double-hung is always straightforward. Replacing a double-hung with a single-hung requires confirming the single-hung's net clear opening still satisfies R310.2, or qualifying under the 702.5 exemption with the largest fitting size. Our impact windows installation team confirms egress compliance on every bedroom opening before submitting permits.

Florida Existing Building Code 702.4 triggers a fall-protection requirement on operable window replacements in one- or two-family homes. It applies when 3 conditions are all true. First, the bottom of the clear opening sits less than 24 inches above the finished floor. Second, the opening passes a 4-inch sphere test, meaning a child could fit through. Third, the window is more than 72 inches above grade. When all 3 conditions apply, the contractor must install a window opening control or fall prevention device. That device must comply with ASTM F2090. R310.1.1 explicitly permits ASTM F2090 devices on egress windows. Adding fall protection does not disqualify a window from serving as emergency egress. The device must be releasable from the inside without tools. Both the PGT SH5500 and DH5560 offer an optional window opening control device certified to ASTM F2090. This detail matters most in second-floor bedrooms in Miami, Fort Lauderdale, and similar urban markets. Sill heights in those areas are often low by design. For a deeper dive into impact code compliance across HVHZ counties, read our Florida building code impact window requirements overview.