Blown insulation is a good choice for reaching odd-shaped nooks and crannies. A ruler or yardstick inserted into the insulation should measure it at 10 to 14 inches deep to meet South Carolina’s recommended R-38 value.
Attic insulation plays an important role in keeping your home comfortable and your power bills low, but before you head to the local home improvement store to buy more, first make sure your house is well sealed.
“Insulating without air sealing is kind of a waste of money,” says Bennie Marshall, owner of Carolina Green Energy Systems.
Marshall estimates that 90 percent of manufactured homes and 75 percent of stick-built homes leak air through cracks in ductwork, gaps around plumbing, unsealed outlets and countless other small defects. That’s the air you’re paying to heat or cool flowing uselessly out of your home.
The best way to find leaks? Let a professional conduct a comprehensive home energy audit, including a blower door test. This test uses a powerful fan to draw air out of the house, lowering the interior air pressure and allowing higher-pressure outside air to seep in through unsealed gaps or cracks. Once identified, those spaces should be sealed before any other upgrades are considered.
You might spend about $250 to $450 for a comprehensive home energy audit. Be sure to use an expert, such as those certified by the Building Performance Institute or the Home Energy Rating System. Your co-op can recommend local professionals, or you can search for one here and here.
A professional audit may identify other problems that need attention before adding insulation, and a trained auditor can recommend the most cost-efficient places to make improvements.
“You need to test before you touch anything,” Marshall advises. “Otherwise, you’re just literally shooting in the dark.”