Unfaced wall insulation is easier to cut and install, making it the better choice for a DIY project. It’s also more affordable. But if it’s unfaced, you’ll likely need to add a vapor barrier to reach your desired R-value and efficiency, as it doesn’t offer any moisture barrier.

Faced insulation uses paper or foil to create a built-in barrier and doesn’t require an extra step. It’s also more fire-resistant and safe. But it’s quite a bit more expensive and a little bit harder to work with as a DIYer.

Doubling the insulation in your home also doubles the R-value of said insulation. In other words, by adding more insulation, you can reduce the heat loss by half. Most homes benefit from increasing insulation. Older homes, in particular tend to have less insulation as is, so doubling your insulation could drastically reduce your energy bills, keep your home more comfortable, and take the strain off your HVAC system.

The time required for insulation installation can range from a few hours to a few days, with most projects taking 1-3 days to complete. The final duration depends on the project's size and complexity, the area size, and the type of insulation being installed.

Installing sheets of plywood over attic insulation is a popular choice, especially in storage spaces. That said, insulation works by trapping hot air—so it needs extra space to expand and be effective, or you might reduce the energy efficiency of your home. 

It’s important that you never compress the insulation by installing flooring directly on top of it. In many houses, you’ll need to install a subfloor before putting plywood over insulation in your attic.