Attic insulation in Hanahan SC - a cooler upstairs and a steadier power bill

Yes, in an existing vented attic the standard guidance is to seal every opening in the attic floor first, with sealant, one-part spray foam or rigid blocking. The same guidance calls for metal blocking and collars around hot flues, covers over recessed can lights that aren't rated to be buried in insulation, and solid blocking over large holes and open soffits. That's the order we work in, because insulation laid over open gaps just lets air keep moving through it.

An insulation job of any kind in the Charleston area usually runs about $1,300 to $4,500, and that range covers all insulation work, not attic jobs alone. Where your attic lands depends on its size, how much is already up there, whether old material comes out and how much sealing it needs. Your written estimate is where you get the figure for your own attic.

It might, but each program serves its own customers, so it depends on which utility serves your address. Through March 31, 2027, eligible Dominion Energy Home Energy Check-up Plus participants may receive 90% toward qualifying attic insulation, air sealing and duct sealing, up to $2,880, and Dominion's EnergyShare program supports weatherization and energy-saving work for eligible residential electric customers. Berkeley Electric Cooperative offers its customers a 5% loan for long-term energy improvements and puts insulation upgrades high on its list, though those terms come from an undated page and may change. We work in Hanahan and the cities around it, so check with your utility first and we'll plan the job around what it offers.

Usually not once the attic is already well insulated. A radiant barrier can cut the heat moving from the attic into the house by about 40%, which typically works out to 8% to 12% of a year's cooling costs, but most of that payoff comes in attics with little or no insulation and very little comes once the attic reaches R-30, the rating for how well insulation slows heat. If yours is thin, I'll tell you straight whether a barrier or more insulation is the better use of your money.

When the heating and cooling equipment and ducts sit in the attic, insulating under the roof deck instead of the attic floor brings them inside the insulated part of the house, so any air leaking from the ducts still heats or cools your rooms. That kind of sealed attic needs a way to remove moisture, so that gets planned as part of the job. It costs more than sealing the floor and topping up loose fill, which is why I look at where your equipment sits before recommending either one.

Let us know about every fuel-burning appliance before the work starts, because how much fresh air the house needs has to be worked out before any air sealing. That fresh air keeps the indoor air healthy and lets furnaces, stoves, ovens and fireplaces vent properly, and sealing a house tighter changes how much outside air leaks in. We go over those appliances with you at the estimate so the plan accounts for them.