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Typical ranges, repair vs. replace, and what to look for in a new patio door.
INSULATIONSpray foam vs. blown-in insulation: which is right for a Texas attic?
Short answer: for most DFW homes with a standard vented attic, air sealing plus blown-in insulation on the attic floor gives the best comfort for the money. Spray foam on the underside of the roof costs more. It can make sense when your ductwork and HVAC sit in the attic, or when the attic is hard to air seal from the floor.
How each one works
- Blown-in insulation (fiberglass or cellulose) is blown loose across the attic floor. The attic stays vented and hot, and the insulation keeps that heat out of your rooms. It works best after the gaps in the attic floor are air sealed.
- Spray foam is usually sprayed on the underside of the roof deck. It seals and insulates in one step and turns the attic into a semi-conditioned space, so ducts up there sit in cooler air.
R-value: spray foam vs. blown-in
R-value measures how well insulation resists heat. The U.S. Department of Energy lists these approximate values per inch:
- Open-cell spray foam: about R-3.6 per inch
- Closed-cell spray foam: about R-6 per inch
- Blown cellulose: about R-3.2 to R-3.8 per inch
- Blown fiberglass: about R-2.2 to R-2.7 per inch
Blown-in reaches high R-values cheaply because the attic floor has room for depth. Spray foam reaches them in less space, at a higher price.
Cost: spray foam vs. blown-in
Angi's June 2026 Dallas data lists blown-in at about $1 to $4.25 per square foot and spray foam at about $2 to $5.25 per square foot. Spray foam usually covers the larger roof area rather than the attic floor, so whole-project totals often run several times higher. Treat these as broad ranges, not quotes. Attic insulation cost in DFW
Common spray foam concerns
- Installation quality matters. The chemicals are mixed on site. Follow the manufacturer's guidance on staying out of the home during and after spraying.
- Roof inspections. Foam covers the underside of the roof deck, which can make leaks and decking harder to see. Some home inspectors and buyers ask about it.
- Code requirements. Spray foam in attics generally needs an approved ignition or thermal barrier, so check that it's included.
- Moisture. The roof assembly has to be designed correctly for our hot, humid climate.
Which is right for your home?
- Choose air sealing plus blown-in for a standard vented attic, when you want the best return for the money, or when you're topping up existing insulation.
- Consider spray foam when the HVAC and ducts are in the attic and the roofline is complex, or as part of a larger renovation.
- Either way, seal first. Air sealing is what makes any insulation perform. How we seal and insulate
Home energy savings calculator
What could attic insulation save you each month?
Enter your square footage, windows and doors for a quick, broad estimate.
The bottom line
Spray foam is a strong product at a premium price. For most DFW attics, sealing the attic floor and blowing in insulation to the recommended level gets you most of the comfort for much less. We'll look at your attic and explain which approach fits.
Sources: U.S. DOE Building America, spray polyurethane foam guide; U.S. DOE Building America Solution Center, loose-fill insulation; Angi, attic insulation cost in Dallas, TX (updated June 2026).
