Attic insulation: what a Charlotte house actually needs

The Department of Energy puts our region in climate zone 3, which means a target around R-38 for attic floors. Plenty of Charlotte homes from the 80s and 90s sit at R-11 to R-19. That gap is most of why upstairs bedrooms are unbearable in August.

Blown-in is the workhorse

For a vented attic with decent access, blown-in fiberglass or cellulose is usually the right call. It is cheap per R-value, fast to install, and easy to top up. Cellulose settles a little more but handles air movement better. Either one gets a typical attic from R-19 to R-38 for a price most homeowners find reasonable.

When spray foam earns its cost

Spray foam on the roof deck turns the attic into conditioned space. That is worth real money in two cases: your HVAC equipment and ducts live in the attic, or you are fighting a complicated roofline where blown-in cannot reach. Outside those cases, foam is often double the price for comfort you could have bought with blown-in plus air sealing.

Questions worth asking an installer

• Will you air seal the attic floor before blowing? If the answer is no, keep calling around.
• What is the finished depth in inches, and where are the depth markers?
• How will you keep soffit vents clear? Baffles matter in our humidity.
• Does the quote include a blower-door test or at least a before-and-after inspection?

Related reading: why air sealing comes first and what to do under the house.