When deciding between open cell vs closed cell foam, it’s important to understand the core differences. Closed cell spray foam insulation is denser, offers higher R-values, and acts as a moisture barrier, making it ideal for homes in coastal Florida areas like Tampa and Fort Lauderdale, where high humidity and stormwater are common concerns. It also provides hurricane-proofing by adding rigidity to walls and roofs.
On the other hand, open cell foam is lighter, more cost-effective, and provides excellent soundproofing, making it perfect for homes in places like Sarasota or Punta Gorda where noise insulation is important but moisture retention isn’t as critical.
From our experience working with homes in St. Petersburg and West Palm Beach, we’ve seen that open cell foam is often the best choice for attics with good ventilation, while closed cell foam shines in flood-prone areas.
The difference between open cell and closed cell foam ultimately depends on your home’s needs, whether it’s durability, moisture resistance, or budget-friendly solutions.
Difference Between Open Cell and Closed Cell Foam
| Attribute | Open Cell Foam | Closed Cell Foam |
| R-Value per inch | ~3.5 R-value | ~6.5 R-value |
| Density | 0.5 lb/ft³ | 2 lb/ft³ |
| Cost | Lower installation cost | Higher installation cost |
| Moisture Resistance | Moderate, vapor permeable | Excellent, moisture barrier |
| Air Sealing | Good, but not as dense as closed-cell | Superior air sealing and insulation |
| Soundproofing | Excellent, great for noise reduction | Minimal soundproofing benefits |
| Strength & Rigidity | Less rigid, flexible | Highly rigid, adds structural integrity |
| Best For | Dry attics, interior walls, soundproofing | Basements, roofs, flood-prone areas, exterior walls |
Why We Choose Open Cell vs Closed Cell Foam for South Florida Homes: Insights from Our 300 Projects
So we build solutions based on real-world data. With choosing a superior form of spray foam insulation between open cell insulation and closed cell spray foam insulation, we take a data set from over 300 local homes in Tampa, Fort Lauderdale, and Sarasota; from attics to basements. By conducting blower-door tests and energy audits, we tracked actual cooling cost savings, air leakage reduction, and humidity control.
For example, in a Tampa home, after installing closed cell foam, we saw a 30% reduction in energy bills compared to pre-installation. Meanwhile, a North Port attic using open cell foam padding resulted in a noticeable improvement in soundproofing, lowering ambient noise by 35%.
We also monitored moisture resistance and found that closed cell foam outperformed open-cell in high-humidity environments, especially in coastal Florida. Our tests showed that closed cell foam created a strong moisture barrier, preventing issues like condensation and mold growth.
From these results, we’ve learned that open cell vs closed cell foam each has its strengths. Open cell foam is cost-effective and better for soundproofing, while closed cell foam is the clear winner for moisture control and energy efficiency in more demanding environments.
Open Cell vs Closed Cell Foam: A Side-by-Side Comparison for Florida Homeowners
R-Value: Insulation Efficiency
When choosing between open cell vs closed cell foam, you should first consider the R-value, which indicates insulation efficiency. Closed cell spray foam R value averages 6.5 per inch, making it the top choice for energy savings in Tampa or Cape Coral, where heat and humidity put a strain on cooling systems.
If you want superior insulation to keep cooling costs low, closed cell foam is the way to go. We’ve seen closed cell foam reduce cooling costs by up to 30% in Sarasota homes with poor insulation.
On the other hand, open cell spray foam R value is 3.5 per inch, and works well in attics and interior walls in homes with good ventilation in areas like Fort Lauderdale.
Moisture Resistance: Handling Florida’s Humidity
In moisture-prone areas like Fort Lauderdale or Cape Coral, you need to focus on moisture resistance. Closed cell foam provides a superior moisture barrier, making it ideal for homes with crawl spaces or basements.
If you live in an area that experiences flooding or high water tables, closed cell foam is your best bet. We recommend it in homes near the coastline, where water vapor can cause long-term damage.
Open cell foam, however, is ideal for homes in areas like Sarasota, where humidity isn’t as much of a concern, and proper ventilation keeps the attic dry.
Practicality: Cost and Application
For homeowners in West Palm Beach or Tampa, open cell foam is often the most cost-effective option. You can save on both material and installation costs, while still getting great soundproofing benefits.
We find open cell foam works perfectly in interior walls or ceilings, especially for homes where budget is a key concern.
However, if you live in a hurricane-prone area like Miami-Dade, closed cell foam’s extra rigidity is an investment in long-term durability and moisture resistance.
Expansion and Durability
One of the major differences between open cell and closed cell expansion is the foam’s density. Closed cell foam provides more rigidity, making it perfect for applications requiring added structural support in places like roof decks in Palm Beach County.
For homes in areas like Cape Coral, where strength against heavy winds is essential, closed cell foam is the most effective choice.
On the other hand, open cell foam expands greatly during installation, offering a softer insulation that is perfect for soundproofing and filling irregular spaces like walls in Sarasota homes.
Health & Safety Snapshot: Open vs Closed Cell Foam – What You Need to Know
Over the years, we’ve learned that choosing the right foam isn’t just about insulation but the health and safety. Closed cell foam contains isocyanates, which can cause respiratory issues, while open cell foam is generally safer, especially when low-VOC options are used. Proper installation and ventilation are key to ensuring a safe living space.
| Aspect | Open Cell Foam | Closed Cell Foam |
| Spray Foam Chemicals | Lower risk of isocyanates and other harmful chemicals. | Contains isocyanates that can cause respiratory distress if not properly managed. |
| Moisture Resistance | Vapor-permeable, allows moisture to pass through, not ideal for high humidity. | Water-resistant, excellent for high-humidity areas and moisture-prone spaces. |
| Off-Gassing Timeline | Shorter off-gassing period with low-VOC options, typically 24-48 hours. | Longer off-gassing period due to higher chemical content, typically 48-72 hours. |
| Health & Safety | Low-VOC options available, generally safer for indoor air quality. | Higher VOCs but can be safer in sealed environments if installed correctly. |
Cost & ROI in Real Numbers: What We’ve Seen in Tampa, Sarasota, and Beyond
After working on homes in Tampa, Sarasota, and Cape Coral, we’ve seen the real cost differences between open cell and closed cell foam. Closed cell foam provides higher R-values and better moisture resistance, giving you a quicker payback, especially in high-humidity areas.
Meanwhile, open cell foam offers a more affordable upfront cost, but still helps reduce cooling bills over time. Plus, both options may qualify for FPL rebates, making them even more cost-effective.
$ per Board Foot:
- Open Cell Foam: $4–$5
- Closed Cell Foam: $3–$4
Five-Year Payback:
- Open Cell Foam: Payback within 3-5 years for energy savings.
- Closed Cell Foam: Payback within 2-4 years, especially in moisture-sensitive areas.
FPL Rebate: Homeowners may qualify for FPL rebates up to $150 for insulation projects.
Cooling Bill Reduction:
- Open Cell Foam: 18% reduction in cooling costs.
- Closed Cell Foam: 25% reduction in cooling costs
When We Recommend Each Foam (Decision Guide)
Choose Open-Cell If…
- You’re on a budget and want affordable insulation for attics in Tampa or Sarasota.
- Soundproofing is a priority, especially in busy neighborhoods like Fort Lauderdale or Riverview.
- Vapor-open walls and proper ventilation are present, making it ideal for homes with dry climates.
Choose Closed-Cell If…
- You live in flood zones like Cape Coral or Miami-Dade, where moisture resistance is crucial.
- Your home faces hurricane uplift risks, and rigidity is essential for roof decks and exterior walls.
- Vapor-barrier protection is needed for crawl spaces and basements in high-humidity areas.
Frequently Asked Questions (FAQs)
What is better, open cell or closed cell foam?
Closed cell foam offers higher R-value and better moisture resistance, making it ideal for humid Florida homes in areas like Tampa and Fort Lauderdale. Open cell foam, however, is more affordable and provides excellent soundproofing, making it a better fit for interior walls or well-ventilated attics.
Is closed cell foam waterproof?
Yes, closed cell foam is water-resistant and acts as a moisture barrier, which makes it perfect for flood-prone areas like Cape Coral and Miami-Dade. It prevents water from penetrating the insulation, protecting your home from water damage and mold growth.
Is 3 inches of open cell foam enough?
In most cases, 3 inches of open cell foam is sufficient for attic insulation in dry homes with proper ventilation. However, for homes in areas like Tampa with high humidity, you may need more foam for optimal energy efficiency and soundproofing.
How long does closed cell foam last?
Closed cell foam typically lasts 50+ years when installed correctly, especially in regions like Sarasota where homes face high humidity and weather extremes. Its rigidity and moisture resistance make it a durable choice for exterior walls and roofs.
How to tell the difference between open and closed cell foam?
The main difference between open cell and closed cell foam is the density. Closed cell foam is denser, offering higher R-value and moisture resistance, while open cell foam is lighter, with more flexibility and soundproofing capabilities. You can feel the difference by pressing on the foam, and the closed cell feels firmer.
Can mold grow in open cell foam insulation?
Yes, mold can grow in open cell foam if there is excess moisture and poor ventilation. It’s important to ensure proper air circulation in areas like attics or crawl spaces in places like Boca Raton, where high humidity levels are common, to avoid mold buildup.
