Spray Foam vs Blown-In Insulation: Which is Right for Your Home?

Making the Right Choice for Your Home

Here's what we know for sure: Glendale summers are brutal. When it's 105 outside and your attic's hitting 150 degrees, you need insulation that actually works. The wrong choice means years of high energy bills and rooms that never feel comfortable. The right choice means walking into a cool house in August without dreading your SCE bill.

Let's break down both options - the honest pros and cons, real costs, and which situations favor each one. We've installed thousands of jobs across LA County, so we'll tell you what we've actually seen work, not just what the manufacturer's brochure says.

Blown-In Insulation: The Budget-Friendly Workhorse

Blown-in insulation is exactly what it sounds like - loose material we blow into your attic through a big hose. It settles into every nook and cranny, flows around pipes and wires, and fills spaces that batts can't reach. Most attic jobs we do use this stuff because it works great and doesn't break the bank.

You've got two main choices: fiberglass or cellulose. Both get the job done, but they've got different strengths.

Fiberglass

Made from recycled glass, spun into those fluffy fibers you've probably seen. Gets you R-2.2 to R-2.7 per inch. Won't rot, won't absorb water, won't grow mold. Doesn't settle as much as cellulose over time either. It's the straightforward, reliable option.

Cellulose

Cellulose is basically shredded newspaper treated with fire retardant. Sounds unimpressive, but it actually insulates better - R-3.2 to R-3.8 per inch. It's denser, which means better air-blocking. Also 85% recycled content if that matters to you. Downside: if it gets wet, you've got problems.

What Installation Looks Like

We show up, park the blowing machine in your driveway, and run a hose into your attic. One person feeds the machine, another one's up in the attic directing the flow. Start in the far corners, work back toward the access. Takes about 4-6 hours for most Glendale homes. We seal up the major air leaks and install baffles at the eaves so your ventilation still works.

What's Good About Blown-In

• Price: $1-2 per square foot. Cheapest option that actually works.
• Speed: In and out in one day. Minimal disruption.
• Coverage: Gets into all those weird spots older homes have.
• Layerable: Can go right over your existing insulation if it's in decent shape.
• No demolition: We're not tearing anything apart.

What's Not So Great

• Air sealing: Helps with air movement, but it's not airtight like spray foam.
• Settling: Loses 10-20% height over time. We install extra to account for this.
• Depth: Need more inches to hit the same R-value as spray foam.
• Moisture: Cellulose especially - if your roof leaks, the insulation's toast.

When Blown-In Makes Sense

Standard attic floor with plenty of headroom. Topping off old insulation that's just not deep enough. Those 1960s ranch homes in Crescenta Highlands with funky joist spacing. Any situation where you need good results without spending a fortune.

Real Pricing

$1 to $2 per square foot installed. A typical 1,500 sq ft Glendale attic runs $1,500 to $3,000 to bring up to R-38. That includes materials, labor, basic air sealing, and baffles.

Spray Foam: The Premium Performer

Spray foam is the high-end option. Two chemicals mix at the spray gun, react on contact, and expand into a solid foam that sticks to everything. It insulates AND air-seals at the same time - that's the big difference. Nothing else on the market does both jobs in one application.

Open-Cell Foam

Spongy, flexible, expands like crazy - up to 100x its liquid volume. Gets you R-3.6 to R-3.8 per inch. Great for sound dampening if you've got noisy neighbors or live near the 134. Air can still move through it slightly, so it's not a vapor barrier, but it seals gaps better than any blown-in product.

Closed-Cell Foam

This is the dense, rigid stuff. R-6 to R-7 per inch - highest you can get. Blocks air, moisture, and vapor completely. Just 1.5 inches qualifies as a vapor retarder. It even adds structural strength to walls. This is what we use in crawl spaces, rim joists, and anywhere moisture's a concern.

How We Install It

Specialized equipment, trained crew, the whole deal. The chemicals come in separate drums, get heated and pressurized, mix right at the gun. We apply thin layers that cure in seconds, building up to the thickness you need. You'll want to stay out of the house for about 24 hours while it fully cures - that's non-negotiable.

Why People Love Spray Foam

• Air sealing: Complete barrier. No drafts, period.
• R-value: More insulation per inch means you need less thickness.
• Moisture protection: Closed-cell stops water and vapor dead.
• Longevity: Never settles, never degrades. It's there for good.
• Structural: Closed-cell actually stiffens walls.
• Sound: Open-cell kills noise better than anything.

The Downsides

• Cost: 2-4x more than blown-in. There's no getting around it.
• Not DIY: This isn't a weekend project. You need pros.
• Curing time: 24 hours out of the house.
• Permanent: Once it's there, it's there. Hard to work around later.
• Installation matters: Bad mix ratios cause problems. Hire someone who knows what they're doing.
• Prep work: Usually need to remove old insulation first.

Where Spray Foam Shines

Homes that leak air like a sieve. Cathedral ceilings where you can't vent the roof. Crawl spaces with moisture issues. Those hillside homes in Verdugo Woodlands with limited attic space. Anywhere you need maximum performance in minimum thickness. If your HVAC's in the attic (common in Glendale), spray foam on the roof deck makes that whole space semi-conditioned.

Real Pricing

$3 to $6 per square foot installed. Open-cell's at the low end, closed-cell at the high end. A 1,500 sq ft attic runs $4,500 to $9,000. More than blown-in? Definitely. Worth it in the right situation? Often yes.

Side-by-Side: What Actually Matters

Here's the quick reference if you don't want to read all the details above.

So Which One Do You Actually Need?

Let's cut through the confusion. Here's our honest take based on what we see in Glendale homes every day.

Go With Blown-In If:

• Budget matters: You need results without breaking the bank. Blown-in gets you 80% of the benefit at 40% of the cost.
• Your house is reasonably tight: Built in the 90s or later? Doesn't feel drafty? Blown-in's probably all you need.
• Topping off old insulation: Got 4 inches and need 12? We just add more on top. Easy.
• Plenty of attic space: Depth isn't an issue? Blow in as much as you want.
• Older home with weird framing: Those craftsman bungalows in downtown Glendale have all kinds of irregular spacing. Blown-in handles it.
• You care about environmental impact: Cellulose is 85% recycled newspaper. Hard to beat that.

Go With Spray Foam If:

• Your house leaks like crazy: Feel drafts? AC runs nonstop? Some rooms never get comfortable? Spray foam seals everything.
• Limited space: Cathedral ceilings, low attics, tight crawl spaces - spray foam does more with less thickness.
• Moisture problems: Closed-cell is basically waterproof. Great for crawl spaces.
• You're staying long-term: Planning to be in this house for 15+ years? Spray foam's higher upfront cost makes sense.
• Noise is an issue: Live on a busy street? Under a flight path? Open-cell foam kills sound.
• Already doing major work: Walls open for a remodel? Perfect time to spray.

The Real Numbers

For a typical 1,500 sq ft attic here in Glendale:

• Blown-in cellulose to R-38: $1,800 - $2,500
• Blown-in fiberglass to R-38: $2,000 - $3,000
• Open-cell spray foam: $4,500 - $6,000
• Closed-cell spray foam: $6,000 - $9,000

Yeah, spray foam's 2-4x more. But if your home's got serious air leakage, it can pay for itself in 3-5 years through energy savings. We've seen some Glendale homes cut their summer electricity by 35-40% with spray foam - that's real money.

The Smart Middle Ground: Use Both

Here's what we actually recommend for a lot of Glendale homes: use spray foam where it matters most, then blow in the rest. You get spray foam's air sealing where you need it without paying spray foam prices for your entire attic.

How It Works

We spray a thin layer of closed-cell foam on all the leak points - around can lights, plumbing penetrations, electrical boxes, HVAC boots. Maybe 1-2 inches. That creates your air barrier. Then we blow cellulose or fiberglass over the top to get your R-value where it needs to be. Best of both worlds.

Why This Approach Works

• Cost: 40-50% less than full spray foam, but 90% of the performance.
• Targeted: You're paying for spray foam only where it actually matters.
• Flexible: We customize based on your home's specific leak patterns.
• Proven: Studies show hybrid systems perform within 10-15% of full spray foam.

Great For:

• Older homes with lots of can lights and penetrations
• Those 1970s-80s tract homes in Sparr Heights that were built without much air sealing
• Anyone who wants better than blown-in but can't swing full spray foam
• Complex attics where full spray foam would be overkill

If your home was built before 1990, this is usually our recommendation. You've got air leakage that needs addressing, but you don't necessarily need to spray foam every square inch to fix the problem.