At On the Mark Spray Foam Insulation, we’ve had countless homeowners ask us the same question: Should I go with fiberglass batts or blown-in insulation? And we get it insulation isn’t something most people think about until comfort or energy bills become a problem. But that one decision can shape your home’s efficiency, moisture control, and long-term comfort for years.
We created this guide to give you an honest, no-fluff breakdown of how fiberglass batt insulation stacks up against blown-in insulation. You’ll walk away knowing exactly which option suits your space, budget, and energy goals all backed by our real-world experience working in homes just like yours.
Fiberglass batts are the familiar pink or yellow rolls found in most attics built over the past few decades. They’re pre-cut and installed between joists, usually in walls, attics, and crawl spaces. The material is made from fine strands of glass woven into a thick, pliable sheet that traps air and slows heat movement.
At On the Mark Spray Foam Insulation, we’ve seen fiberglass batts work well in new builds where every stud bay is a standard width. But they’re less forgiving in older homes with irregular framing or obstacles like wiring and plumbing.
Blown-in insulation, often made from loose fiberglass or cellulose, is installed using a machine that fills every gap and odd-shaped cavity. It’s especially useful in attics and retrofits where existing insulation needs to be supplemented or replaced.
We use blown-in frequently when we’re upgrading attic insulation in older homes. It flows around beams, pipes, and electrical boxes, creating a more continuous thermal barrier a real advantage when air sealing is the goal.
Installing batts may look straightforward, but performance depends on precise placement. Gaps, compression, or misalignment can all reduce R-value the measure of how well insulation resists heat flow.
We’ve often been called in to reinsulate spaces where batts were poorly installed or deteriorating. It’s not uncommon to find entire sections with zero coverage or insulation jammed in too tightly, which kills its effectiveness.
Blown-in insulation fills gaps that batts simply can’t. Whether it’s a drafty corner or an irregular attic floor, blown-in offers better coverage especially when paired with air sealing. That’s why we often recommend it when upgrading from batts in older homes that never had proper insulation in the first place.
While both fiberglass batts and blown-in insulation can offer similar R-values on paper, performance in the field is where they diverge. Batts can only meet their rated R-value if they’re installed perfectly a tall order in real-world conditions.
Blown-in insulation, when installed by a qualified team like ours, reaches the desired depth and density to achieve consistent R-values across the entire surface. That reliability can translate into lower energy bills and steadier indoor temperatures.
One of the issues we often see with batt insulation is settling, moisture absorption, and shifting over time. In contrast, blown-in insulation tends to stay where it’s placed, especially when installed with netting or in dense-pack applications. It maintains its insulating ability longer, with less maintenance needed.
Air leakage is the enemy of comfort and efficiency. With batts, gaps around framing and obstacles allow air to bypass the insulation we call this thermal bridging. In winter, that means cold drafts; in summer, it’s heat creeping in where it shouldn’t.
We see this all the time in attics that were insulated with batts decades ago. Even when the insulation looks intact, the air movement underneath tells a different story.
Blown-in insulation naturally fills those hidden gaps. When combined with strategic air sealing which we always recommend and often perform as part of the job it provides a tight, effective thermal boundary. This stops heat transfer and reduces HVAC strain year-round.
Fiberglass batts are typically cheaper upfront and easy to find at any hardware store. But the lower price tag often comes with compromises in performance, installation quality, and lifespan. We’ve replaced batts that were less than 10 years old because of mold, pests, or poor fit.
While blown-in insulation costs a bit more initially, the energy savings often offset the difference in a few short years. Plus, its ability to resist settling and retain performance makes it a smart long-term investment.
We’ve worked with homeowners who saw immediate improvements in comfort and a noticeable drop in energy bills within months of switching to blown-in.
Traditional fiberglass batts can shed tiny particles during installation or when disturbed, which may irritate skin, eyes, or lungs. Some types are now manufactured with reduced irritation potential, but they still require caution.
We always use proper protective equipment and containment procedures during batt removal and replacement, especially in older homes with deteriorated insulation.
Blown-in insulation, particularly fiberglass varieties with minimal dust, presents fewer health risks during installation. When properly installed and contained, it doesn’t off-gas or create air quality issues. We’ve had many clients comment on the immediate difference in comfort and air freshness after upgrading.
Choosing the right insulation doesn’t have to be a gamble. At On the Mark Spray Foam Insulation, we take the guesswork out and help you make the smartest choice for your home’s comfort, efficiency, and future. We’re not here to push a product we’re here to recommend what actually works based on your unique space.
When you partner with us, you get more than insulation. You get expert advice, professional installation, and long-term peace of mind. Let’s talk about your home. Let’s make it better together.
Reach out to us at (813) 921-0444 or info@onthemarksprayfoam.net to schedule your consultation today.
If your attic has lots of obstructions, gaps, or needs a performance boost, blown-in insulation is usually the better fit. For wide-open, new construction attics, batts may suffice if properly installed.
Not when installed by professionals. We contain all areas, use targeted equipment, and clean up thoroughly so your space is left spotless.
Yes, but it depends on the condition of the existing batts. If they’re moldy, compressed, or rodent-damaged, we recommend removing them first. We’ll assess your setup and advise accordingly.
Blown-in insulation often lasts 20–30 years or more with proper installation. Batts tend to degrade faster, especially if exposed to moisture or poor ventilation.
Cellulose blown-in insulation is often made from recycled paper and treated with fire retardants, making it a more sustainable choice. Fiberglass batts and blown-in options are increasingly made with recycled glass as well.
Blown-in insulation usually costs more upfront, but the long-term energy savings often outweigh the initial expense. We’re always transparent about pricing and help you understand the return on investment.
Yes, both fiberglass batts and blown-in options reduce sound transmission. Blown-in tends to perform better in irregular cavities, which helps reduce airborne noise.
Not always. We evaluate each home to determine if removal is needed. Sometimes topping up makes sense; other times, full removal and reinstallation are more effective.
Only if you’re confident in sealing every gap, maintaining uniform depth, and handling materials safely. Most DIY jobs we’ve seen end up needing corrections which costs more in the long run.
Call us at (813) 921-0444 or email info@onthemarksprayfoam.net. We’ll schedule a no-pressure consultation and walk you through your options in plain English.