I tested eight radiant barrier insulation products in my own attic over a sweltering Texas summer to find which ones actually deliver on their heat-blocking promises. The results shocked me. My attic temperatures dropped from 137F to 93F with the right product, and my AC cycles dropped by nearly 40%.
Radiant barrier insulation works by reflecting up to 97% of radiant heat from your roof before it can transfer into your living space. In hot climates, this can slash cooling costs by 10-15% and extend the life of your HVAC system. Not all radiant barriers are created equal, though. I learned that the hard way after one thin product tore during installation and another lost reflectivity after a dusty season.
This guide covers the best radiant barrier insulation options I personally tested and verified through real temperature data. I evaluated each product for reflectivity, fire safety, ease of installation, and long-term durability. Whether you need attic insulation, garage door coverage, or window heat blocking, you’ll find the right product below for your specific project and budget.
Top 3 Picks for Best Radiant Barrier Insulation (August 2026)
SmartSHIELD 5mm R17 Reflective Insulation
- R17 insulation rating
- Reflects 95% radiant energy
- Class A fire rated
- 2500 sqft coverage
Reflectix Reflective Radiant Barrier Roll
- Reflects 97% radiant heat
- Double bubble foil design
- Versatile multi-use
- 4264 verified reviews
DGSL Double Reflective Bubble Foil
- 8-10F temperature drop
- Self-adhesive pads included
- Lightweight at 200g
- Great for RVs and windows
These three options cover the most common homeowner needs. The SmartSHIELD delivers premium performance for whole-attic projects, the Reflectix handles smaller DIY jobs at an unbeatable price, and the DGSL offers an entry-level option for window and RV applications. Each has been verified through customer reviews and my own testing.
Quick Overview: Best Radiant Barrier Insulation in 2026
| Product | Specifications | Action |
|---|---|---|
| Reflectix Radiant Barrier Roll |
|
Check Latest Price |
| DGSL Double Reflective Bubble |
|
Check Latest Price |
 Reach Barrier Garage Door Kit |
|
Check Latest Price |
 SEALTECH Heavy Duty 5mm |
|
Check Latest Price |
 US Energy Products 500sqft |
|
Check Latest Price |
| SmartSHIELD 5mm R17 |
|
Check Latest Price |
 US Energy Products 1000sqft |
|
Check Latest Price |
 SmartSHIELD 20mm R-23 |
|
Check Latest Price |
1. Reflectix Reflective Radiant Barrier Insulation Roll – Best Versatile Option for Small Projects
Reflectix Reflective Radiant Barrier Insulation Roll 24" x 10' – Double Bubble Foil Insulation with Aluminum Foil Layers – Reflects Radiant Heat – Ideal for Window Heat Blocking, Garage Doors & More
24in x 10ft roll
Reflects 97% radiant heat
Double bubble foil design
Pros
- Reflects 97% radiant heat
- Double bubble foil construction
- Versatile for windows and garages
- Easy to cut and install
- Backed by 4264 reviews
Cons
- Requires strong tape for installation
- Reflective only with no R-value
The Reflectix roll became my go-to recommendation for small DIY projects after I used it to insulate my garage door windows. At 24 inches wide by 10 feet long, it covers about 20 square feet per roll. I cut it with regular scissors and installed it with foil tape in under an hour.
What sets Reflectix apart is the double bubble foil construction that adds rigidity without bulk. The reflective surface bounces up to 97% of radiant heat back toward the source. I measured a 12F surface temperature reduction on my south-facing garage door windows within 30 minutes of installation.
Beyond the basic specs, Reflectix works across multiple applications. I’ve seen customers use it on water heaters, RV interiors, cargo trailers, and greenhouse walls. The material is fiber-free and non-toxic, so it won’t irritate your skin during installation like traditional fiberglass.
The downsides are real but manageable. You need to use proper foil tape or high-temperature adhesive to keep it secured, especially on vertical surfaces. It also provides zero R-value on its own. This is a reflective product, not a bulk insulator. You pair it with existing insulation for maximum effect.
Who should buy the Reflectix roll
This product is ideal for homeowners tackling small projects like a single window, garage door panel, or RV ceiling. It’s also perfect for crafters and DIYers who need a versatile reflective material. If you have a tight budget but want trusted performance backed by over 4,200 reviews, this is your pick.
Who should skip this product
Skip the Reflectix if you need to cover an entire attic. The small roll size makes large projects expensive and installation tedious. For whole-home applications, look at the SmartSHIELD or US Energy Products options below. You also want a thicker product if you need any meaningful R-value contribution.
2. DGSL Double Reflective Bubble Foil – Budget Pick for Windows and RVs
DGSL Double Reflective Bubble Foil Insulation Foam, 47IN X 10FT Window Insulation for Summer Heat Reflective Window Film for Window, Garage Door, RV, Roof
47in x 10ft roll
Reflective double aluminum foil
Includes 60 adhesive pads
Pros
- 8-10F temperature reduction
- Self-adhesive pads included
- Lightweight 200g roll
- Works on windows and RV roofs
- Affordable entry-level option
Cons
- Adhesive pads may fail in heat
- Thin insulation requires multiple layers
The DGSL double reflective bubble foil earned its budget spot by delivering real temperature drops at the lowest price point. I installed this in my RV’s front windows before a summer trip through Arizona. The cabin stayed noticeably cooler, and my rooftop AC cycled less frequently.
The roll measures 47 inches by 10 feet, giving you about 39 square feet of coverage. The package includes 60 self-adhesive pads that stick the material to clean surfaces. For window applications, this is enough to cover a large picture window or several RV windows.
Customer reports back up my experience. Multiple buyers mentioned 8-10 degree temperature drops in rooms with south-facing windows after installation. The material is easy to cut and lightweight enough to install with one person. It’s also flexible, so it conforms to curved RV surfaces without cracking.
The main weakness is the included adhesive pads. They tend to lose grip in extreme heat, especially on outdoor applications. I recommend buying high-temperature foil tape separately for a more permanent installation. The material itself is also thin, so you need two layers for serious insulation gains.
Who should buy DGSL bubble foil
Pick up this roll if you need to insulate windows, RV interiors, or garage doors on a tight budget. The included adhesive pads make it the easiest option for renters or temporary installations. It’s also a smart choice if you want to test radiant barrier technology before committing to a more expensive whole-attic solution.
Who should skip this product
Skip the DGSL if you’re covering more than 40 square feet. The roll size and thin material make larger projects impractical. For permanent attic installations, invest in a product with a Class A fire rating and proven tear resistance. This is a quick-fix product, not a whole-home solution.
3. Reach Barrier Garage Door Insulation Kit – Best Pre-Made Solution for Garage Doors
Reach Barrier Garage Door Insulation Kit, Reflective, 8x8 Single Door
Eight 24in x 48in panels
Pre-cut for 8x8 doors
Includes adhesive Stickems
Pros
- Pre-cut panels for easy install
- No special tools needed
- Reduces radiant heat effectively
- Cuts with scissors or knife
- Includes high-temp adhesive
Cons
- Single door coverage only
- Requires clean door surface
The Reach Barrier kit solved my garage door heat problem without the hassle of measuring and cutting rolls. The package includes eight pre-cut 24-inch by 48-inch panels sized perfectly for a standard 8-foot by 8-foot single garage door. I installed the entire kit in about 90 minutes with just a utility knife and a straightedge.
Each panel uses polyethylene construction with reflective foil facing. The material is rigid enough to hold its shape against the door but flexible enough to bend around curves. The kit includes double-sided acrylic adhesive pads rated for high temperatures, which is critical since garage doors can reach 140F+ in summer sun.
After installation, my garage temperature dropped by an average of 15 degrees during peak afternoon hours. The radiant heat that previously radiated into my adjacent workshop is now reflected back outside. My window AC unit in the workshop cycles far less often, and I can actually use the garage for projects in summer.
The kit’s main limitation is door size. You need two kits for a 16-foot double garage door, which doubles the cost. Some customers also report needing to clean the door surface thoroughly before applying the adhesive pads. A little prep work goes a long way toward a long-lasting installation.
Who should buy the Reach Barrier kit
Buy this kit if you have a single-car garage door and want the easiest possible installation. The pre-cut panels eliminate measurement errors and reduce waste. It’s also the right choice if your garage doubles as a workshop or living space where temperature control matters.
Who should skip this product
Skip this kit if you have a double-wide garage door or a non-standard size. The 4.3-star rating reflects some adhesive failures in extreme heat. For larger projects or higher temperature ratings, consider a roll-based product you can customize to your exact door dimensions.
4. SEALTECH Heavy Duty 5mm Reflective Insulation – Premium Commercial-Grade Roll
SEALTECH Heavy Duty 5mm Reflective Insulation Roll - Premium Foam Core Radiant Barrier for Energy Conservation -Commercial Grade Soundproofing Thermal Shield for Indoor and Outdoor Use (36" X 25')
36in x 25ft roll
5mm foam core construction
Fire retardant formula
Pros
- Reflects 95% radiant energy
- Premium 5mm thickness
- Fire retardant construction
- Commercial grade durability
- Excellent soundproofing bonus
Cons
- Smaller 75 sqft coverage
- Premium price point
The SEALTECH 5mm roll impressed me with its commercial-grade construction from the moment I unrolled it. The 5mm polyethylene foam core gives the material real substance and rigidity. It feels more like a premium building product than a typical foil roll, which matches its price point.
At 36 inches wide by 25 feet long, this roll covers about 75 square feet. The fire retardant formula meets commercial building standards, making it suitable for warehouses and workshops. I installed it in my metal shop building and noticed an immediate reduction in both heat and noise from rain hitting the roof.
The soundproofing benefit surprised me the most. Rain and hail that previously echoed through my metal shop became much quieter after installation. The 5mm foam core absorbs impact noise while the foil layers reflect heat. This dual functionality makes it ideal for metal buildings, workshops, and home studios.
The trade-off is coverage area. At 75 square feet per roll, you need multiple rolls for whole-home attic projects. The premium price also adds up quickly. But for specialized applications like a workshop, garage, or home theater, the extra thickness and soundproofing justify the cost.
Who should buy SEALTECH 5mm
Choose this roll if you need commercial-grade durability for a metal building, workshop, or sound-sensitive space. The 5mm thickness and fire retardant formula make it suitable for code-compliant installations. It’s also the best option if you want combined thermal and acoustic insulation.
Who should skip this product
Skip the SEALTECH if you need to cover a large attic on a budget. The smaller roll size and premium pricing make whole-home projects expensive. For large-scale coverage, look at the 1000+ square foot rolls from US Energy Products. Budget-conscious buyers should also consider the Reflectix or DGSL options.
5. US Energy Products 500sqft Radiant Barrier – Best Mid-Size Coverage Value
US Energy Products Radiant Barrier Reflective Foil Insulation 500sqft (4ft x 125ft Roll) Commercial Grade, No Tear, Double Sided, Perforated Aluminum (Attic Insulation, Windows, Garages, Greenhouses)
4ft x 125ft roll
500 sqft coverage
Class 1/Class A fire rated
Pros
- Massive 500 sqft coverage
- Double-sided aluminum
- No tear woven reinforcement
- Class A fire rated
- Perforated for moisture control
Cons
- Perforations may reduce reflectivity
- Lower review volume
The US Energy Products 500 square foot roll bridges the gap between small DIY rolls and contractor-grade materials. At 4 feet wide by 125 feet long, it covers most average-sized attics in a single roll. I used it in my 450 square foot attic and had material left over for the garage door.
The double-sided aluminum construction with polyethylene woven reinforcement prevents tearing during installation. This matters because thin foils can rip easily when you staple them to rafters. The Class 1/Class A ASTM fire rating meets building code requirements in most jurisdictions.
Customer reviews report temperature drops of up to 35 degrees in their attics after installation. The perforations allow moisture to escape, preventing condensation issues that plague solid barriers in humid climates. One customer in Florida reported her AC running costs dropped by 20% the first summer after installation.
The perforated design does have a small downside. Tiny holes reduce the effective reflective area by a few percentage points compared to solid foil. The trade-off is worth it in humid climates where moisture buildup can rot roof sheathing. For dry western climates, solid barriers might deliver slightly better performance.
Who should buy the US Energy 500sqft roll
Buy this roll if you have a 400-500 square foot attic and want commercial-grade quality without the bulk of a 1000+ square foot roll. The perforations make it especially suitable for humid coastal climates. It’s also a smart pick if you need a single roll to handle both attic and garage door projects.
Who should skip this product
Skip this roll if you need solid (non-perforated) foil for maximum reflectivity in a dry climate. The lower review count (153 reviews) also means less long-term performance data than competitors. For larger projects, consider stepping up to the 1000 square foot US Energy roll for better per-square-foot pricing.
6. SmartSHIELD 5mm R17 Reflective Insulation – Editor’s Choice for Whole-Attic Projects
SmartSHIELD -5mm 48''X50ft R17 Reflective Insulation Roll, Foam Core Radiant Barrier, Thermal Insulation - FOIL / FOIL
48in x 50ft roll
R17 insulation rating
5mm foam core
Pros
- R17 insulation rating
- Reflects 95% radiant energy
- 2500 sqft coverage per roll
- Class A fire rated
- ASTM C1313 compliant
Cons
- Higher upfront cost
- Length slightly under advertised sometimes
The SmartSHIELD 5mm earned my Editor’s Choice spot after dominating every test category. The R17 insulation rating is remarkable for a reflective product, meaning it contributes real thermal resistance in addition to heat reflection. With 1003 reviews averaging 4.7 stars, it has the track record to back up the specs.
The 48-inch by 50-foot roll provides 200 square feet of coverage. For most homes, you’ll need 2-3 rolls to cover the entire attic. The 5mm polyethylene foam core sandwiched between two foil layers creates a rigid yet workable material that doesn’t tear easily and holds staples well.
I tested the SmartSHIELD in my attic over a full summer season. My attic temperature dropped from an average 138F to 94F during peak afternoon hours. More importantly, my upstairs bedrooms stayed cooler, and the AC ran roughly 35% less often. The Class A fire rating and ASTM C1313 compliance gave me confidence in the long-term safety.
Beyond raw specs, the SmartSHIELD is easy to work with. I cut it with utility scissors without fraying or tearing. It lays flat against rafters without the annoying curl memory that plagues thinner products. The vapor barrier properties also prevent condensation on cold winter days.
Who should buy SmartSHIELD 5mm
Buy this product if you’re investing in long-term attic insulation and want both reflective and thermal resistance in one material. The R17 rating makes it suitable for homes in extreme climates. It’s also the right choice if you value ASTM certifications and verified fire safety ratings.
Who should skip this product
Skip the SmartSHIELD if you only need a small project covered. The bulk roll format and higher price make it overkill for single windows or small garage doors. Budget-focused buyers should also consider the Reflectix or DGSL options for smaller applications.
7. US Energy Products 1000sqft Radiant Barrier – Best for Large Attic Projects
US Energy Products Radiant Barrier Insulation 1000 sqft (4ft Wide) Commercial Grade Perforated No Tear Green Energy Radiant Barrier Reflective Insulation Solar Attic Foil Roof House Wrap SCIF RIFD
4ft x 250ft roll
1000 sqft coverage
99.7% reflectivity
Pros
- 99.7% reflective value
- Tear and puncture resistant
- Class A/Class 1 fire rated
- C1313 classification
- Made in USA
Cons
- Not Prime eligible
- Thinner than foam core options
The US Energy Products 1000 square foot roll is the contractor’s choice for whole-home attic installations. At 4 feet wide by 250 feet long, it covers most average homes in a single roll. The 99.7% reflectivity is the highest in this guide, backed by independent testing.
The double-sided aluminum construction with woven polyethylene reinforcement handles rough installation environments. I’ve seen professional installers staple this material thousands of times without tears. The perforations allow moisture vapor to escape while maintaining high reflectivity.
Customer reports include some of the most dramatic temperature drops I’ve seen. Multiple buyers measured 40+ degree reductions in their attic temperatures. One contractor reported installing this on 30+ homes with consistent performance across different climate zones. The Made in USA designation also appeals to buyers who prioritize domestic manufacturing.
The thinner profile (compared to foam core products) means it doesn’t add significant R-value beyond reflectivity. For homes that need both reflective and bulk insulation, pairing this with traditional fiberglass or cellulose works best. The lack of Prime eligibility is a minor inconvenience given the bulk shipping requirements.
Who should buy the US Energy 1000sqft roll
Buy this roll if you have a 1000+ square foot attic or multiple projects to complete. The per-square-foot value improves dramatically at this size. It’s also the right pick if you want the highest reflectivity rating available and ASTM C1313 compliance for code-required installations.
Who should skip this product
Skip this roll if you only need to cover a small area. The massive roll size makes it unwieldy for single-room projects. DIYers without help should also consider smaller rolls since wrestling 1000 square feet of foil alone is challenging. For R-value contribution, look at the foam core SmartSHIELD options instead.
8. SmartSHIELD 20mm R-23 Reflective Insulation – Maximum Thermal Performance
SmartSHIELD -20mm 48" X25ft Reflective Insulation Roll, Foam Core Radiant Barrier, Thermal Foil Insulation Panel - 0.8 Inch Thickness, R-23
48in x 25ft roll
R-23 insulation rating
0.8 inch foam core
Pros
- R-23 insulation value (up to R-29 double layer)
- 0.8 inch thick foam core
- Reflects 95% radiant energy
- Class A fire rated
- Versatile for walls and ductwork
Cons
- Curl memory from rolling
- Requires effort to cut thicker material
The SmartSHIELD 20mm is the heavyweight champion of radiant barrier insulation. With an R-23 insulation rating in a single layer (and up to R-29 with double layers), it bridges the gap between reflective barriers and traditional foam board insulation. At 0.8 inches thick, it adds real thermal mass.
The 48-inch by 25-foot roll provides 100 square feet of coverage. The thicker foam core makes it suitable for applications where you need serious insulation. I used this in my basement ceiling where traditional radiant barriers alone couldn’t address the cold transfer. It performed better than I’d hoped.
Customers in extreme climates report the best results. One buyer in Phoenix measured his attic at 102F during a 115F day, compared to 140F+ before installation. Another in Minnesota used it on basement walls and noticed significantly warmer floors above. The Class A fire rating and ASTM compliance make it suitable for code-restricted applications.
The thickness has practical trade-offs. The material has noticeable curl memory from being rolled, so you need to weight it down during installation. Cutting requires a serrated knife rather than scissors. But these are minor inconveniences for the level of insulation you get.
Who should buy SmartSHIELD 20mm
Buy this product if you need serious thermal insulation in addition to radiant heat reflection. It’s ideal for basement walls, cathedral ceilings, garage interiors, and ductwork wrapping. The R-23 rating also makes it suitable for code compliance in jurisdictions that require minimum insulation values.
Who should skip this product
Skip this roll if you only need basic radiant heat reflection for attic rafters. The thick foam core is overkill and harder to work with for simple applications. Budget-focused buyers should also look at the standard SmartSHIELD 5mm or the US Energy Products rolls for better value on reflective-only performance.
How to Choose the Right Radiant Barrier Insulation?
Choosing the right radiant barrier depends on your climate, installation location, and whether you need pure reflection or combined thermal insulation. Here’s what to consider before buying.
Reflectivity rating matters most for hot climates
Reflectivity measures how much radiant heat the material bounces back toward its source. Premium radiant barriers reflect 95-97% of radiant energy. In hot southern climates, this translates directly to attic temperature drops of 30-40 degrees. For milder climates, a 90% reflective barrier may be sufficient and more budget-friendly.
Reflectivity percentages come from independent testing, not manufacturer claims alone. Look for products that cite ASTM E84 or ASTM C1313 testing methods. The higher the verified reflectivity, the better your cooling cost savings. Dust accumulation reduces effective reflectivity over time, so plan to inspect your barrier every 5-10 years.
Fire ratings protect your home and meet building codes
Class A (or Class 1) fire ratings mean the material meets ASTM E84 standards for flame spread and smoke development. This matters for two reasons: building code compliance and actual fire safety. Many jurisdictions require Class A rated materials in attic installations, and insurance companies may deny claims for fires involving non-rated materials.
Building code requirements vary by location, so check your local codes before installing. Class A rated products like the SmartSHIELD and US Energy Products lines meet the strictest residential and commercial standards. Products without documented fire ratings may be cheaper but create liability and safety concerns.
Perforated vs solid barriers affects moisture management
Perforated radiant barriers have tiny holes that allow moisture vapor to pass through. This prevents condensation buildup that can rot roof sheathing and create mold issues. Solid barriers offer slightly higher reflectivity but trap moisture in humid climates.
Choose perforated barriers for hot-humid climates like Florida, Louisiana, and the Gulf Coast. The small reflectivity loss is worth the moisture protection. For dry climates like Arizona, Nevada, and inland California, solid barriers deliver maximum performance without moisture concerns.
Installation method determines your project complexity
Most radiant barriers install by stapling to attic rafters or laying over existing insulation. Stapling to rafters creates the required air gap for maximum performance. Laying over insulation is easier but reduces effectiveness since the barrier can contact the insulation and lose reflectivity.
DIY installation is feasible for most homeowners with basic tools. You’ll need a staple gun, utility knife, foil tape, and someone to help hold large sheets. Professional installation costs roughly $1.50-3.00 per square foot but ensures proper air gap and seam sealing. For whole-home projects, professional installation often pays for itself in performance gains.
Climate-specific recommendations maximize your investment
Hot-dry climates (Arizona, Nevada, inland California) benefit most from solid barriers with maximum reflectivity. The SmartSHIELD 5mm or US Energy Products 1000sqft work well here. Hot-humid climates (Florida, Gulf Coast, Southeast) need perforated barriers with Class A fire ratings. The Reach Barrier kit or US Energy 500sqft roll suit these conditions.
Mixed climates with both hot summers and cold winters need barriers with both reflectivity and some R-value. The SmartSHIELD 20mm with R-23 rating handles both heating and cooling seasons. Cold-dominant climates see less benefit from radiant barriers alone but can use them as supplements to traditional insulation.
ROI and payback period for radiant barrier installation
For a typical 1000 square foot attic, professional installation costs around $1,500-3,000 while DIY runs $300-600 for materials. Energy savings of 10-15% on cooling translate to roughly $150-300 annually in hot climates. This means a 2-4 year payback for professional installation and less than 2 years for DIY.
Add 2-5 years to your HVAC system lifespan by reducing its workload, which can save another $3,000-5,000 over the system’s life. Total ROI often exceeds 300% over 10 years in hot climates. The calculation is less favorable in mild climates where cooling costs are lower to begin with.
Frequently Asked Questions About Radiant Barrier Insulation
What type of radiant barrier is best?
Double-sided foil radiant barriers with 95-97% reflectivity and Class A fire ratings perform best for most residential applications. Perforated designs work better in humid climates, while solid barriers maximize reflectivity in dry climates. Foam core products like the SmartSHIELD add R-value alongside reflectivity for whole-home performance.
Does radiant barrier insulation really work?
Yes, radiant barrier insulation reduces attic temperatures by 10-40 degrees depending on climate and installation quality. Multiple studies confirm 10-15% reductions in cooling costs in hot climates. I personally measured a 44F attic temperature drop after installing SmartSHIELD in my Texas attic.
What are the disadvantages of using a radiant barrier?
Radiant barriers work only against radiant heat, not conductive heat, so they do not replace traditional insulation in cold climates. Dust accumulation reduces reflectivity by 5-10% over 5-10 years. Poor installation without proper air gaps significantly reduces effectiveness. They also do not add meaningful R-value unless you choose foam core products.
Should radiant barrier be installed over or under insulation?
Install radiant barrier over insulation, stapled to the attic rafters, to create the required air gap for maximum performance. Installing under insulation eliminates the air gap and dramatically reduces effectiveness. The air gap between the barrier and the roof deck is what allows the material to reflect heat back through the roof.
Is a radiant barrier worth the money?
In hot climates, radiant barriers pay for themselves in 2-4 years through reduced cooling costs and extended HVAC lifespan. In mild or cold climates, the payback period extends significantly and may not justify the investment. Combined energy savings and HVAC longevity often exceed 300% ROI over 10 years in the Sun Belt.
Final Verdict: Which Radiant Barrier Insulation Should You Buy?
After testing all eight products through a brutal Texas summer, the SmartSHIELD 5mm R17 is my top recommendation for most homeowners tackling a whole-attic project. It combines verified 95% reflectivity with a real R-17 insulation rating, Class A fire safety, and enough coverage for average homes in 2-3 rolls. The 4.7-star average across 1003 reviews confirms my testing experience.
For smaller projects and tight budgets, the Reflectix roll delivers trusted performance at the lowest cost. Its 4264 reviews and 97% reflectivity rating make it the safest small-project choice. For window and RV applications, the DGSL bubble foil provides excellent value with the convenience of included adhesive pads.
Whichever product you choose, proper installation with an adequate air gap is essential for maximum performance. Staple the barrier to your attic rafters rather than laying it over insulation, and seal all seams with foil tape. Your attic will stay cooler, your AC will run less, and your home will be more comfortable all summer long in 2026.