Blowing insulation into an attic is a straightforward job once you have the right setup. Here's what to gather before rental day:

An insulation blower. This is the machine that shreds and feeds bagged insulation through a hose, giving you even, fluffed coverage instead of dense clumps. Rental units range from smaller residential machines to higher-output cyclone-style blowers that move material faster over larger attics, like this cyclone insulation blower for rent in Tullahoma, Tennessee.

Bagged insulation material. Cellulose and fiberglass are the two most common choices for blown-in attic insulation. Buy enough bags based on your attic's square footage and target R-value (most building supply stores post a coverage chart on the bag).

A sturdy ladder. Attic access hatches are usually in a hallway or closet ceiling, and you'll want a stable step ladder rated for the height, not a kitchen stool. A 6-foot fiberglass step ladder works for most standard ceiling heights, while an 8-foot fiberglass step ladder gives extra reach for higher hatches or vaulted areas.

Safety gear. A dust mask or respirator, safety glasses, gloves, and long sleeves. Blown insulation, especially fiberglass, creates airborne particles that irritate skin, eyes, and lungs.

A flashlight or headlamp, plywood boards to kneel on across the joists, and a helper if possible to feed the hopper while you handle the hose in the attic.

1. Inspect the attic first. Before adding new material, check for existing damage, moisture stains, or pest activity. Blowing new insulation over a wet spot just hides a problem that will get worse. Also confirm your attic has proper baffles installed near the eaves to keep soffit vents clear of insulation.

2. Measure your current insulation depth. Use a ruler or tape measure at several points across the attic floor. Compare this to your region's recommended R-value (most of the U.S. calls for R-38 to R-60 in attics, which translates to roughly 12 to 16 inches of blown cellulose or slightly more for fiberglass).

3. Seal air leaks before insulating. Gaps around recessed lights, plumbing stacks, and the attic hatch itself let conditioned air escape no matter how much insulation you add on top. A few minutes with expanding foam or caulk here pays off.

4. Set up the insulation blower. Position the machine near the attic access, ideally in a garage or driveway close to a window or the pull-down ladder, since the hose needs to reach every corner of the attic. Load bags into the hopper as directed, most machines have a shredding mechanism that breaks apart compressed bales as it feeds the hose.

5. Start blowing insulation into the attic from the farthest corner. Work backward toward the access point so you're not walking over freshly laid material. Keep the hose moving in a steady sweeping motion rather than dumping in one spot, which creates uneven depth and settling later.

6. Check depth as you go. Insulation depth markers (small cardboard rulers) are cheap and worth stapling to a few joists ahead of time so you can glance and confirm coverage without stopping to measure constantly.

7. Avoid covering vents, recessed lighting rated for exposure, and the attic access hatch itself. Leave a small clearance around non-IC-rated fixtures per your local code.

8. Finish and inspect. Once you've reached target depth everywhere, do a final walk-through with a flashlight checking for thin spots, especially near the edges and over ceiling joists where blown material tends to settle less than in open bays.

Both materials work well when installed correctly, but they behave differently through the blower and over time.

Cellulose is treated recycled paper fiber. It's denser, settles into tight spaces well, and offers better sound dampening. It does settle 15 to 20% over the first year, so installers typically add extra depth upfront to compensate.

Fiberglass blown-in insulation is lighter, doesn't absorb moisture the way cellulose can, and resists settling better over time, meaning the depth you install is closer to the depth you'll have five years later. It's also less dense, so it can take slightly longer to reach the same R-value per inch as cellulose.

If you're unsure which to choose, check what your existing attic insulation is made of and consider matching it, since mixing types isn't a problem structurally but can make future depth checks harder to read accurately.

Depth is the single biggest factor in whether your DIY blown-in insulation job actually performs. A few practical tips:

Use the coverage chart on the insulation bag, not a general rule of thumb. Chart numbers account for the specific product's settled thickness and bags-per-square-foot ratio, which varies by brand and material.

Install a few depth markers before you start blowing insulation into the attic. These small rulers staple to the top of joists and give you an at-a-glance reference so you're not second-guessing coverage in low light.

Don't skimp near the eaves. This is the area most homeowners under-insulate because it's harder to reach with the hose. Use a shorter wand extension if your blower kit includes one.

Plan for two passes on large attics. If you're covering more than 1,500 square feet solo, doing the bulk of the attic first and returning for a second finishing pass helps you catch thin spots you missed the first time around.

If your project also involves other renovation work nearby, such as retiling a bathroom or patching drywall in an adjacent room, it's worth scheduling those separately from the insulation day since dust and material tracked between rooms only adds cleanup time. For related equipment needs on bigger renovation projects, guides like how to use a drywall lift or how to retile a shower cover the equipment side of those jobs in more detail.