This is one of the most common questions we hear from Oklahoma City homeowners: "Should I get spray foam or blown-in insulation?" It's a good question, and the honest answer is that it depends on your home, your budget, and what you're trying to accomplish.
We install both types every week. We don't have a financial incentive to push one over the other. What follows is a straightforward comparison based on eight-plus years of experience insulating existing homes across the OKC metro.
The Basics: What Are We Comparing?
Blown-In Insulation
Blown-in insulation is loose material — either fiberglass or cellulose — that gets blown into place using a specialized machine. It's the most common insulation method for attic floors and can also be dense-packed into wall cavities. The material fills around obstacles like wiring, pipes, and ducts, conforming to irregular shapes and gaps.
Spray Foam Insulation
Spray foam is a two-part chemical mixture that's sprayed as a liquid and expands into a solid foam. It comes in two types: open-cell (lighter, softer, less expensive) and closed-cell (denser, stronger, more expensive). Spray foam adheres directly to surfaces and expands to fill every crack and gap, creating both an insulation layer and an air barrier in one step.
Head-to-Head Comparison
Cost
This is where the two options differ most dramatically:
- Blown-in fiberglass: $1.00 - $1.75 per square foot
- Blown-in cellulose: $1.25 - $2.50 per square foot
- Open-cell spray foam: $1.50 - $2.50 per square foot
- Closed-cell spray foam: $2.50 - $4.00 per square foot
For a 1,500-square-foot attic, you might pay $1,500 - $3,750 for blown-in versus $2,250 - $6,000 for spray foam. That's a meaningful difference, especially on a tight budget.
Winner: Blown-in — significantly less expensive for the same area coverage.
R-Value (Insulating Power)
R-value measures how well insulation resists heat flow. Higher is better.
- Blown-in fiberglass: R-2.5 per inch
- Blown-in cellulose: R-3.5 per inch
- Open-cell spray foam: R-3.7 per inch
- Closed-cell spray foam: R-6.5 per inch
Closed-cell spray foam offers nearly double the R-value per inch compared to most blown-in options. That matters when space is limited — like in wall cavities or low-clearance areas.
Winner: Spray foam — especially closed-cell, which packs more insulating power per inch.
Air Sealing
This is where spray foam really shines. Spray foam doesn't just insulate — it creates an air-tight seal wherever it's applied. Air leakage accounts for a huge portion of energy loss in Oklahoma homes, sometimes as much as 30-40% of your heating and cooling costs.
Blown-in insulation does not seal air leaks. It slows heat transfer, but air can still move through and around it. That's why we always recommend air sealing before adding blown-in insulation — sealing the gaps around electrical penetrations, plumbing, recessed lights, and the attic hatch first.
Winner: Spray foam — it's insulation and air barrier combined.
Moisture Resistance
Oklahoma's humidity is no joke, especially in summer. Moisture management matters for insulation longevity.
- Blown-in fiberglass: Doesn't absorb water but can trap moisture, potentially leading to mold if there's a leak.
- Blown-in cellulose: Treated with borate for fire and pest resistance, but can absorb moisture. If it gets wet, it can lose R-value and potentially grow mold.
- Open-cell spray foam: Can absorb some water. Not ideal for areas with direct water exposure but handles normal humidity well.
- Closed-cell spray foam: Excellent moisture resistance. Acts as a vapor barrier. Best choice for areas prone to moisture, like crawl spaces.
Winner: Closed-cell spray foam for moisture-prone areas. For standard attic applications, both types perform fine with proper ventilation.
Durability and Longevity
Both types last a long time when properly installed:
- Blown-in insulation: 20-30 years. Can settle over time (cellulose more so than fiberglass), losing some R-value. Can be displaced by wind in open attics if not properly installed.
- Spray foam: 30+ years with virtually no settling or degradation. It stays exactly where it's applied.
Winner: Spray foam — longer lifespan with no settling.
Installation Speed
For a typical attic project in an OKC home:
- Blown-in insulation: Usually completed in 2-4 hours
- Spray foam: Usually completed in 4-8 hours, and the area needs to be clear of occupants during application due to fumes (typically 24 hours for full curing)
Winner: Blown-in — faster installation with less disruption.
Best Applications for Each Type in Oklahoma Homes
When We Recommend Blown-In
- Attic floors with adequate ventilation: This is the bread-and-butter application. If your attic is vented and you just need to bring the insulation level up to R-38 or higher, blown-in is the most cost-effective way to do it.
- Topping off existing insulation: If you have R-19 and want to get to R-38, adding blown-in on top of your existing insulation is fast and affordable.
- Budget-conscious projects: When the budget is tight but the house needs better insulation, blown-in combined with air sealing delivers the best bang for your buck.
- Wall cavity fills (dense-pack): Dense-packed cellulose blown into wall cavities through small drill holes is an excellent way to insulate existing walls without tearing them apart.
When We Recommend Spray Foam
- Encapsulating attics with HVAC equipment: Many Oklahoma City homes have their air handler, furnace, or ductwork in the attic. Spraying the roofline with foam brings all that equipment into conditioned space, making your entire system more efficient.
- Crawl spaces: Oklahoma's humid climate and clay soil make crawl spaces a prime area for moisture problems. Closed-cell spray foam on crawl space walls is one of the best solutions we install.
- Rim joists and band boards: The area where your foundation meets the framing is a notorious source of air leaks. Spray foam seals and insulates in one step.
- Homes with severe drafts: If your house is particularly leaky and air sealing alone isn't enough, spray foam can solve air infiltration and insulation in one application.
- Metal buildings or pole barns being converted: For any non-traditional building envelope, spray foam adheres directly to metal and creates a seamless insulation and vapor barrier.
What We Typically Recommend for OKC Homes
After insulating hundreds of existing homes across Oklahoma City, Edmond, Norman, Moore, and the surrounding metro, here's our most common recommendation:
For most existing homes on a reasonable budget: Air sealing the attic floor, followed by blown-in cellulose or fiberglass to R-38 or higher. This combination gives you 80-90% of the performance of spray foam at roughly half the cost. It's the best value in insulation, period.
For homes with attic HVAC equipment: Spray foam on the roofline to encapsulate the attic. This is one of the situations where spray foam pays for itself faster because your ductwork and air handler immediately become more efficient.
For crawl spaces: Closed-cell spray foam on the crawl space walls, with a vapor barrier on the ground. Oklahoma's soil conditions make this a worthwhile investment.
For maximum performance regardless of budget: Spray foam throughout. If energy efficiency and comfort are your top priorities and the budget allows, spray foam is simply the superior product.
The Honest Truth
Here's something most insulation companies won't tell you: for many Oklahoma City homes, blown-in insulation with proper air sealing is all you need. Spray foam is a great product, but it's not always worth the premium. We'd rather save you money and do the right job than upsell you on something you don't need.
That's one reason we have a 5.0-star rating across 89+ reviews. We tell people the truth, even when it means a smaller invoice for us.
If you're not sure which option is right for your home, give us a call at (405) 437-0146. We'll come out, look at your home, and give you an honest recommendation — no pressure, no obligation. And remember, 20% of every project we do gets donated to a local nonprofit, so you can feel good about hiring us either way.