Blown-in insulation is the most efficient way to add R-value to an existing attic. Loose-fill fiberglass or cellulose is blown into the attic floor to the correct depth, covering the joists and any existing insulation evenly. It's faster than batt installation, performs well in Tom Green County's climate, and is typically the right choice for attic upgrades in existing homes.

San Angelo sits along the Concho River at the edge of West Texas, a semi-arid transition zone drier than Central Texas but not as extreme as the Panhandle or the Permian Basin further west. Goodfellow Air Force Base anchors a meaningful share of the local economy and housing demand, similar in pattern to Killeen and Abilene, with tract housing built in waves to serve the base's workforce. San Angelo's older housing stock, much of it dating to the mid-20th-century ranching and oil-service economy, commonly carries thin original attic insulation from an era when the city's dry climate was assumed to make cooling loads less of a concern than it's since proven to be as summer temperatures have pushed higher. The region's caliche and limestone-influenced soil generally supports stable slab foundations. San Angelo's dry heat means attic insulation performs somewhat differently here than in humid East Texas — there's less moisture risk, but summer heat gain through an underinsulated roof deck is still the dominant driver of high cooling bills.

Fiberglass vs. Cellulose Blown-In

Blown-in fiberglass is white, light, and maintains its R-value even when it gets slightly damp. Blown-in cellulose (made from recycled paper) is denser, settles more over time, and has slightly better resistance to air movement through the insulation layer. Both are good options — we can advise on the better choice for your specific attic conditions and R-value goals. Neither material is universally the better choice — the right pick usually comes down to a handful of practical factors specific to your attic rather than a general rule.

  • Existing insulation type — blowing cellulose on top of old fiberglass (or the reverse) is generally fine, but a contractor will check compatibility and settling behavior before recommending a mix.
  • Fire and pest resistance — cellulose is treated with borate for fire and pest resistance as part of manufacturing; fiberglass is naturally non-combustible without needing chemical treatment.
  • Attic ventilation — in a well-ventilated attic, both materials perform close to their rated values. In a marginally ventilated attic, fiberglass's better tolerance of incidental moisture can be an advantage.
  • Density and coverage — cellulose's higher density means it can be slightly more resistant to wind-washing near soffit vents, a detail that matters more in attics with significant airflow near the eaves.

How Much to Add and Where

Your contractor measures your existing insulation depth and calculates your current R-value, then tells you exactly how much additional insulation is needed to reach the recommended level for Tom Green County. Depth markers are installed in the attic so you (or a future inspector) can verify the installed depth. The job is clean and typically completed in a few hours for a standard attic. Even coverage matters as much as total depth — a blower hose passed too quickly over an area leaves it thinner than the rest of the attic, which is why depth-marker verification at multiple points, not just near the hatch, is part of a proper job rather than an optional extra.

  • Pre-installation prep — air sealing bypasses and installing baffles at soffit vents (to keep insulation from blocking attic airflow) happens before material goes in.
  • Even distribution — the installer works the attic systematically rather than just filling from one access point outward, which is where uneven coverage most often comes from.
  • Settling allowance — cellulose in particular is blown to a slightly greater initial depth than the target R-value requires, accounting for expected settling over the following months.
  • Depth verification — markers placed at multiple points let you (or a future home inspector) confirm the installed depth without needing to measure by hand.

Have Questions?

We're happy to walk through your situation before you commit. Call us and we'll tell you honestly whether an upgrade makes financial sense for your home.

Call (469) 210-0277

This content is reviewed by the Texas Insulation Pros editorial team and informed by licensed-contractor sourcing, manufacturer documentation, and established industry standards for Insulation. Read our editorial standards.