Impact Window Condensation in South Florida: Causes, Fixes, and What It Means for Your Warranty
You paid good money for hurricane impact windows - and now they look foggy. Whether you're in a Boca Raton townhome, a Weston single-family house, or a Delray Beach condo, impact window condensation is one of the most common complaints homeowners bring to us. The good news: not all condensation is bad news. The less welcome news: some of it absolutely is.
This guide breaks down every type of condensation South Florida homeowners encounter, explains what causes each, walks through your fix options, and gives you a plain-language explanation of how manufacturer warranties handle moisture-related failures in Palm Beach County and Broward County.
Understanding Impact Window Glass in South Florida
Before diving into condensation specifics, it helps to understand what you're actually looking at when you peer at a foggy pane.
Most impact window glass used in South Florida is an insulated glass unit, commonly called an IGU. An IGU consists of two panes of glass separated by a spacer bar filled with desiccant material. The cavity between the panes is typically filled with argon or dry air, then sealed with two layers of sealant: a primary structural seal (usually butyl) and a secondary structural seal (usually silicone or polysulfide).
The laminated interlayer - the PVB or SGP film that makes the glass "impact-rated" - sits inside one or both panes of glass, not in the air gap. This distinction matters when diagnosing condensation because the laminate layer and the IGU seal are two separate systems.
Understanding this construction helps explain why South Florida's unique climate attacks impact windows in ways that homeowners in other states rarely encounter.
The Three Types of Impact Window Condensation
Not all foggy glass is created equal. There are three distinct locations where moisture can appear, and each has a very different cause, fix, and warranty implication.
Type 1: Condensation on the Interior Surface
This is moisture forming on the inside face of your impact window - the side facing your living room, bedroom, or kitchen. It typically appears during the summer cooling season, usually in the morning hours.
What causes it: Warm, humid interior air contacts the relatively cool glass surface. When the glass temperature drops below the dew point of the indoor air, water vapor condenses. This is exactly the same physics that fogs up your bathroom mirror after a shower.
Is it a problem? Generally not a window defect, no. Interior condensation most often points to:
- AC set too cold relative to indoor humidity levels
- Inadequate ventilation or exhaust in kitchens and bathrooms
- Oversized or improperly balanced HVAC systems
- New construction drying out (concrete, drywall, and framing lumber release substantial moisture for 12-18 months after installation)
South Florida reality check: Our average relative humidity runs between 75% and 85% during summer months. If your home is cooled to 68 degrees and indoor humidity hasn't been controlled, interior condensation is almost unavoidable on any glass surface, impact-rated or not.
Fix: Adjust your thermostat slightly upward (70-72 degrees is the commonly recommended sweet spot for South Florida comfort and humidity control), run bathroom exhaust fans during and after showers, and consider a whole-home dehumidifier if the problem persists. A certified energy auditor can identify specific problem areas in homes throughout West Palm Beach, Pembroke Pines, and Fort Lauderdale.
Warranty implication: Interior surface condensation caused by humidity and HVAC factors is almost never covered under a window warranty. This is considered an environmental or homeowner-side condition.
Type 2: Condensation on the Exterior Surface
This is moisture forming on the outside face of the window - the surface exposed to South Florida's outdoor environment.
What causes it: On clear, calm nights, glass radiates heat outward toward the sky faster than the ambient air warms it back up. When the glass surface temperature falls below the outdoor dew point, you get exterior condensation. This phenomenon is called radiative cooling and is more common on windows with high-performance low-E coatings because these coatings are so effective at limiting heat transfer.
Is it a problem? No. Counterintuitively, exterior condensation on your impact windows is actually a sign that your low-E glass is performing as designed. High-efficiency windows allow the glass to cool more rapidly at night because they prevent heat from bleeding back outward from the interior.
Homeowners in Coral Springs, Davie, and Boynton Beach often call concerned about exterior morning fogging, particularly after low-humidity cold fronts push through in November through February. This is completely normal behavior.
Fix: None required. Exterior condensation evaporates as the sun rises and outdoor temperatures climb. It does not damage the window in any way.
Warranty implication: Exterior surface condensation is not a defect and is not covered under any warranty because there is nothing wrong.
For a deeper look at how your glass coatings affect energy performance, see our guide on impact window energy efficiency including SHGC and U-Factor ratings for South Florida.
Type 3: Condensation Between the Panes (Seal Failure)
This is the serious one. Moisture trapped inside the IGU cavity - between the two panes of glass - indicates that the hermetic seal has been breached. This is commonly called "seal failure," "fogged glass," or "failed IGU."
What it looks like: A cloudy, hazy, or milky appearance that seems to be inside the glass rather than on the surface. You cannot wipe it away because the moisture is sealed inside. Over time, it may develop into mineral streaks, white hazing, or visible droplets inside the pane.
This is the type of impact window foggy glass situation that requires action.
What Causes Impact Window Seal Failure in South Florida?
Seal failure is unfortunately more common in South Florida than in cooler, less humid climates. Here's why:
Thermal Cycling Stress
South Florida's temperatures may not get as extreme as northern states, but our daily thermal cycling is relentless. A window in Pompano Beach or Greenacres can swing from 65 degrees at 7 AM to 95 degrees by 2 PM, then back down overnight. Over years, this expansion and contraction fatigues the sealant compounds at the perimeter of the IGU.
Each temperature swing causes the glass panes to expand and contract, working the seals slightly. Over thousands of cycles, even quality sealants can begin to fail.
UV Degradation
South Florida receives some of the highest UV radiation loads in the continental United States. UV radiation degrades organic sealant compounds over time, making them brittle and less flexible. Secondary seals exposed to direct sunlight on south-facing and west-facing elevations tend to fail earlier than those on shaded or north-facing exposures.
For east-facing homes, our guide on impact windows for east-facing homes in South Florida addresses how morning sun exposure affects glass performance and longevity.
Salt Air Exposure
Salt-laden air accelerates corrosion of the metal spacer bars within IGUs. As the spacer corrodes, the bond between spacer and sealant weakens, creating pathways for moisture intrusion. Homeowners within a mile or two of the Atlantic coastline or the Intracoastal Waterway experience accelerated seal degradation compared to inland areas.
Our detailed breakdown of salt-air versus inland microclimates in Palm Beach and Broward explains the hardware and seal lifespan differences across different zones of the county.
If your home sits along a canal or waterway, also review our resource on choosing impact windows for Palm Beach County canal homes, which covers moisture exposure considerations specific to those environments.
Poor Installation
Improperly installed windows fail seals faster. Causes include:
- Incorrect flashing that allows water to pool at the frame base
- Inadequate caulking at the frame-to-wall interface
- Overtightened or undertightened fasteners that stress the frame
- Missing or damaged glazing tape within the frame that allows glass movement
Installation quality has a direct impact on how long your IGU seals last. We cover the most common impact window installation mistakes in South Florida in detail, including several that directly accelerate seal failure.
Pressure Differentials
Homes near the coast or in high-rise buildings experience sustained wind pressure loads that can stress window seals over time. In high-rise buildings on Broward's coastline, the combination of building sway, wind load, and ocean humidity creates an especially aggressive environment for IGU seals.
If you own or manage a unit above the fifth floor, our guide to high-rise impact windows in Broward County addresses the specific pressures at work.
Storm Damage
Even after a window survives a hurricane or tropical storm, the pressure pulses and wind-driven rain exposure can accelerate seal aging. After any significant storm event, a thorough inspection is warranted. Our post-storm impact window inspection guide for Palm Beach and Broward walks through what to look for and when to call a professional.
Can You Fix a Failed IGU Seal?
This is a question we get constantly, and the honest answer is: the IGU itself cannot be resealed in the field. There are commercial products marketed as "defogging" services that drill small holes in the glass, inject cleaning solution, and install vents. These services temporarily reduce the appearance of fogging but do not restore the insulating properties of the sealed unit and are widely considered a cosmetic patch, not a real fix.
The proper solution for impact window moisture between panes is glass replacement - specifically, replacing the IGU (the sealed glass unit) while typically retaining the existing frame.
This is called a glass-only replacement or IGU replacement, and it is significantly less expensive than replacing the entire window assembly. A qualified contractor can swap out the IGU without removing the frame from the wall opening, provided the frame itself remains structurally sound and properly sealed.
In some cases - particularly where the frame has also been compromised or where the seal failure is the result of an installation defect - a full-frame replacement may be warranted. Our comparison of retrofit versus full-frame impact window replacement explains when each approach makes sense.
Impact Window Warranty Coverage: What Palm Beach and Broward Homeowners Need to Know
This is where many homeowners get frustrated, because warranty language is often vague and manufacturer exclusions can seem designed to avoid paying claims. Let's break down what's typical.
What Warranties Typically Cover
Most major impact window manufacturers - including PGT, CGI, and ES Windows, all brands we carry as authorized dealers - offer IGU warranties that cover seal failure under normal use conditions. Standard coverage periods typically range from 10 years to lifetime (transferable or non-transferable) depending on the product line and purchase date.
Covered failures generally include:
- Seal failure occurring under normal environmental exposure
- Manufacturing defects in the sealant materials
- Spacer bar failures related to manufacturing quality
- Glass breakage under some limited circumstances
What Warranties Typically Exclude
Read the fine print carefully. Common exclusions in impact window warranty claims include:
Installation-related failure: If the manufacturer determines the seal failed because of improper installation rather than a product defect, the warranty may be denied. This is why installation by an authorized, licensed contractor matters enormously. Working with an unauthorized installer can void your product warranty entirely.
Damage from exterior causes: Seal failure caused by impact from landscaping equipment, construction activity nearby, or vandalism is typically excluded.
Neglect of maintenance: Failure to maintain proper caulking and seals at the frame-wall interface can allow water intrusion that accelerates IGU failure. Some warranties require evidence of reasonable maintenance.
Condensation on surfaces: As noted above, surface condensation (interior or exterior) is universally excluded because it is not a product defect.
Chemical exposure: Use of harsh cleaning products, paint solvents, or pressure washing that damages seals can void coverage.
Modifications: Any modification to the window unit, including the defogging services mentioned above, can void the warranty.
Transferability in South Florida's Active Real Estate Market
South Florida has one of the most active real estate markets in the country, with significant turnover in cities like Miami Gardens, Deerfield Beach, and Lake Worth Beach. If you are buying a home with existing impact windows, find out:
- What brand and product line are the windows
- When they were installed
- Whether the original warranty is transferable and at what cost
- Whether transfer must be registered within a specific window after sale
Many manufacturer warranties transfer free of charge within 30-60 days of a home sale but may require formal registration. Missing that window means losing the coverage. When you work with us on a new installation, we document everything you need to protect and potentially transfer your warranty.
The Role of Installation Documentation
For a warranty claim to be processed, you typically need:
- Original purchase receipt or invoice
- Installation permit and inspection records
- Manufacturer's warranty registration confirmation
- Photos or documentation of the defect
This is another reason why pulling proper permits matters. Our guide on impact window permit timelines in Palm Beach versus Broward County explains the permitting process in both counties and why cutting corners can have long-term consequences beyond just code compliance.
Preventing Seal Failure: Maintenance Tips for South Florida Homeowners
While no IGU lasts forever, proper maintenance extends the life of your seals significantly.
Regular Cleaning
Clean window frames and glass with mild soap and water. Avoid ammonia-based cleaners, abrasive compounds, or pressure washing directly at window seams. Residue from harsh cleaners can degrade sealants over time.
Annual Caulk Inspection
Once a year - ideally before hurricane season begins in June - inspect the caulking at the frame-to-wall interface on all windows. Look for cracking, separation, or gaps. Reapply exterior-grade, UV-resistant caulk as needed. This prevents water from getting behind the frame and contacting the IGU edge seals.
Our comprehensive guide on coastal impact window maintenance from Jupiter to Hollywood provides a detailed maintenance checklist for South Florida conditions.
Hardware Maintenance
Lubricate operating hardware on casement and awning windows twice a year with silicone-based lubricant. Stiff or binding hardware places stress on the frame and glass unit during operation, accelerating seal fatigue.
Shade and UV Management
Where practical, exterior shading through awnings, overhangs, or landscaping reduces the UV and thermal load on south and west facing windows. This directly extends sealant life.
When to Call a Professional
If you notice fogging between panes that you cannot wipe away, contact a licensed impact window contractor for an assessment. At Window Guys of Florida, our team serves all of Palm Beach County and Broward County, and we can determine whether the issue is covered under your manufacturer warranty, whether an IGU replacement is the right solution, or whether the installation itself contributed to the failure.
We are authorized dealers for PGT, CGI, ES Windows, Andersen, and other leading brands, which means we can source replacement IGUs directly and process warranty claims on your behalf when applicable.
Schedule your free consultation and let us take a look before the problem gets worse or your warranty period expires.
FAQ: Impact Window Condensation in South Florida
Window Guys of Florida has served Palm Beach County and Broward County homeowners for over 25 years. We are licensed, insured, and authorized dealers for the leading impact window and door brands. View our service areas or contact us today for a free in-home consultation.
Frequently Asked Questions
Is condensation on the outside of my impact windows normal in South Florida?
Yes, exterior surface condensation is completely normal and actually indicates your windows are performing well. High-efficiency low-E glass allows the outer pane to cool below the outdoor dew point on clear nights, especially after cold fronts pass through. It evaporates as the sun rises and causes no damage to the window. This is not a defect and is not covered under warranty because nothing is wrong. If you are unsure whether what you are seeing is surface condensation or interior fogging, contact us for a professional assessment.
How do I tell the difference between surface condensation and seal failure on my impact windows?
The key test is simple: try to wipe the moisture away. If it wipes off, it is on the surface - either interior humidity condensing on a cool pane or normal exterior dew. If it cannot be wiped away because the haziness or moisture is inside the glass unit between the two panes, that is seal failure. Failed IGU seals often appear as a milky haze, mineral streaks, or visible droplets locked inside the glass. This type of fogging will not clear on its own and typically worsens over time. A failed seal means the IGU needs to be replaced.
Does my impact window warranty cover foggy glass or seal failure in Palm Beach County and Broward County?
Most major manufacturers including PGT, CGI, and ES Windows include IGU seal failure in their warranty coverage, typically for 10 years to lifetime depending on the product line. However, coverage depends on several factors: the failure must be due to a manufacturing defect or normal environmental exposure, the windows must have been installed by a licensed authorized contractor, and you must have proper documentation including permits and warranty registration. Installation errors, chemical damage, or modifications to the window can void coverage. We help homeowners through the warranty claim process as authorized dealers. Reach out to us for help evaluating your specific situation.
Can foggy impact window glass be repaired without replacing the whole window?
In most cases, yes. When seal failure occurs, the solution is replacing the IGU (the sealed glass unit) rather than the entire window assembly including the frame. This glass-only replacement is significantly less expensive and can typically be done without disturbing the existing frame if it remains structurally sound. Some companies offer 'defogging' services that drill holes and inject cleaning agents, but these are cosmetic patches that do not restore insulating performance and often void your warranty. A proper IGU replacement restores both appearance and energy efficiency. Learn more about when a full-frame replacement is needed in our guide to retrofit vs full-frame impact window replacement.
How long should impact window seals last in South Florida's climate?
Quality impact window IGU seals from reputable manufacturers should last 15 to 25 years under normal South Florida conditions. However, lifespan varies significantly based on several factors: coastal homes within a mile of salt water tend to see earlier seal degradation due to corrosive salt air, south and west-facing windows receive heavier UV and thermal load that ages sealants faster, and improperly installed windows can begin failing within just a few years. Consistent maintenance - annual caulk inspection, gentle cleaning, and hardware lubrication - extends seal life. Read our full coastal impact window maintenance guide for specific tips by location.
If I buy a South Florida home with existing impact windows, am I covered under the original warranty?
It depends on the manufacturer and whether the warranty was properly transferred. Many major brands allow warranty transfers but require formal registration within a set timeframe after the home sale - often 30 to 60 days. Missing that window can mean losing coverage entirely. When buying a home, ask the seller for the original installation invoice, permit documentation, and warranty registration confirmation. If you are unsure about the status of existing windows in a home you've purchased or are considering purchasing, contact our team and we can help you identify the brand, verify coverage status, and assess the current condition of the installed units.