sorell insulation logo
Free Estimate
Free Estimate

Blown Fiberglass vs. Cellulose Insulation: Why Fiberglass is the Winner

by | Aug 11, 2025 | Roof Insulation, Attic Insulation, Calgary Insulation | 0 comments

Blown Fiberglass vs. Cellulose Insulation: Why Fiberglass is the Winner

When it comes to upgrading your attic insulation in Calgary, you have options – but not all blown insulation materials are created equal. At Sorell Insulation, we specialize in blown-in fiberglass insulation, and there’s a good reason we choose it over cellulose every single time. From performance in extreme Alberta winters to long-term value, fiberglass consistently outshines cellulose in real-world conditions. Let’s break down the differences so you can make an informed choice – and avoid costly surprises down the road.

On this page:

Fiberglass Stays Fluffy Vs. Cellulose Settles

One of the biggest issues with cellulose insulation is that it settles over time—meaning the R-value you paid for at install can drop significantly within a few years. That translates into heat loss, uneven coverage, and higher energy bills.

Blown fiberglass? It holds its loft. It stays full, fluffy, and effective—season after season.

Moisture? No Problem

Fiberglass doesn’t absorb water. If your attic ever sees moisture – like a minor roof leak or condensation buildup – fiberglass will dry out and keep performing. Cellulose, on the other hand, is basically shredded newspaper. It soaks up moisture like a sponge, and that opens the door to mold, mildew, and rot in your attic structure.

Naturally Fire-Resistant

Fiberglass is non-combustible – it doesn’t burn, and it doesn’t need chemical treatments to resist fire. Whereas cellulose needs to be treated with flame-retardant chemicals like borate to meet safety standards, but those treatments can break down over time – especially in humid or moist conditions.

Less Dust, Less Mess

Installing blown fiberglass is a cleaner process. It produces less airborne dust, which is better for both homeowners and installers. Cellulose, on the other hand, is known for kicking up clouds of fine dust, which can linger long after the job’s done and be irritating to breathe.

It Stays Where It Belongs

Fiberglass doesn’t slump or slide – even on sloped ceilings or in vertical wall cavities. Cellulose? It can shift over time, especially if the attic isn’t perfectly sealed. That leads to cold spots, reduced performance, and callbacks – which nobody wants.

Pests Aren’t Interested

While fiberglass won’t win any awards for being pest-proof, most critters don’t want to nest in it. It’s itchy, inorganic, and not exactly cozy.

Cellulose, being organic, can attract rodents or insects, especially if the borate treatments wear off.

Long-Term Value and Peace of Mind

Fiberglass insulation like Johns Manville Climate Pro (our go-to product) is built to last. It holds its R-value, doesn’t degrade, and comes with solid manufacturer warranties. That’s long-term performance you can count on. Cellulose may seem cheaper upfront, but over time, it may need replenishing or replacement—driving up the true cost of insulation.

Bottom Line? Fiberglass Wins the Long Game

At Sorell, we don’t just install insulation – we install peace of mind. Blown fiberglass is cleaner, more durable, and better suited to Calgary’s climate. Whether you’re upgrading for comfort, energy savings, or resale value, it’s the smart choice.

Ready to upgrade your attic the right way?

Call us today at (403) 472-2676  Or request a quote online

Serving Calgary and surrounding areas

Expert attic upgrades using blown-in fiberglass insulation

Achieve R60 insulation — clean, efficient, code-compliant

Schedule your free inspection now

Looking for more tips on optimizing your home’s insulation, energy-saving hacks, or updates on our latest services? Follow us on social media for expert advice, and behind-the-scenes insights.

Add your first comment to this post