Attic Insulation in Sherman, TX

The attic is where most homes lose the most energy. In Grayson County's climate, the attic is the primary boundary between outdoor heat and your living space — and if the insulation there is thin, compressed, or missing in areas, your air conditioner is paying for it every month. We upgrade attic insulation for homeowners throughout Sherman and Grayson County.

Sherman, the seat of Grayson County near Lake Texoma and the Oklahoma border, has spent the past several years in the middle of one of the largest industrial investments in Texas history — Texas Instruments' multibillion-dollar semiconductor fabrication campus, along with GlobiTech's expansion, has driven rapid new-home construction to house an influx of skilled workers. That boom sits alongside Sherman's much older core: a historic downtown and surrounding neighborhoods with homes dating to the early 1900s railroad era, many carrying original or minimal insulation typical of pre-1960s North Texas construction. The contrast is stark — new subdivisions built in the last few years to house semiconductor-industry workers meet current energy code with properly depth-rated blown insulation, while homes just a mile or two away in Sherman's older grid are still running on whatever was installed (or never installed) decades ago. Grayson County's North Texas climate brings hot, humid summers and occasional winter ice events, both of which expose the insulation gap between these two housing generations.

Recommended R-Values for Grayson County

The Department of Energy recommends R-38 to R-60 for attics in this climate zone — depending on the existing insulation type and your HVAC efficiency goals. Most older homes in Grayson County have well under this range, particularly those built before the 1990s. We measure your current depth, calculate your existing R-value, and tell you how much to add to reach the recommended level. The measurement itself matters as much as the target number — insulation settles unevenly over decades, so a spot check near the attic hatch can show a very different depth than the same attic's far corners, and a proper assessment measures at several points rather than assuming uniform coverage.

• R-30 to R-38 (roughly 8-12 inches of blown fiberglass, or 10-13 inches of cellulose) — a reasonable minimum baseline, though below what current DOE guidance recommends for this climate zone.
• R-38 to R-49 (roughly 12-16 inches blown, or 13-17 inches cellulose) — the range most contractors target for a standard upgrade in Grayson County.
• R-49 to R-60 (16+ inches) — worth considering for homes with especially high energy costs or where the attic floor area allows for the added depth without other constraints.
• Existing insulation type matters for the math — an inch of blown cellulose and an inch of blown fiberglass don't deliver quite the same R-value, so "how many inches" isn't a complete answer without knowing what material is already up there.

Air Sealing Before Adding Insulation

Adding insulation on top of an air-leaky attic floor delivers less benefit than the R-value suggests. Warm air infiltrating through gaps around light fixtures, plumbing penetrations, and attic hatches carries heat (and moisture) directly into the attic space. Sealing these bypasses before adding insulation is what separates a proper upgrade from just dumping more material in the attic. It's a step that's easy to skip because it isn't visible in the finished job the way a deeper layer of insulation is — but two attics with identical insulation depth can perform very differently in practice depending on whether the bypasses underneath were sealed first.

• Top plates of interior walls — the single most common bypass location, often overlooked because it's hidden under existing insulation.
• Recessed light fixtures — older fixtures not rated for insulation contact need airtight covers before insulation can safely be added around them.
• Plumbing and electrical penetrations — small individually, but numerous enough across a typical attic to add up to a meaningful air leak.
• The attic access hatch — frequently the single largest uninsulated, unsealed opening in the entire attic floor, and one of the easiest to fix.

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.