Saving Energy: Blown-in Insulation in the Attic
Save $1,000 on labor and cut your heating bills with blown in attic insulation.
IntroductionLearn how to insulate your attic yourself with blown-in cellulose insulation, and start saving money on your utility bills. This step-by-step article walks you through every detail of the job, plus you'll learn about attic insulation costs.
- Blower machine
- Caulk gun
- Dust mask
- Leather gloves
- Safety glasses
- Shop vacuum
- Trouble light
- Utility knife
- Cellulose insulation
- Duct tape
- Expanding foam
- Vent chutes
Blown in Insulation Overview
If you need to add insulation in your attic, save big by blowing in cellulose insulation yourself. How much does attic insulation cost? The pros charge $1,500 to $2,000 to do a 1,200-sq.-ft. house. You can do it yourself for about $500. Blowing attic insulation isn’t hard, but it’s dusty, sweaty work. To make insulating an attic easier, grab a helper and set aside two days: one for attic prep and the second to actually blow the insulation. By the end of the weekend you’re going to be sore and tired. But saving $1,000 or more with blown in ceiling insulation will make up for your aching back.
The long-term payoff of insulating an attic is impressive too. You could see your energy bills go down by as much as 15 to 25 percent depending on your climate and existing levels of insulation. And you may also qualify for a tax credit on the blown in attic insulation cost (check with the IRS or at energystar.gov).
To show you how to do the blown in insulation job right, we asked our expert to share his tips for making the job go smoothly and help you avoid the top three attic-insulation mistakes.
Our Blown in Insulation Expert
Arne Olson, the owner of Houle Insulation in Minneapolis, has insulated more than 5,000 homes. “A lot of those homes were insulated by DIYers who didn’t know what they were doing,” says Olson. “They didn’t use enough insulation and they didn’t seal up the attic bypasses or put in vent chutes.” Olson says it’s also common for older insulation to settle over time. “But you can blow cellulose over whatever kind of insulation is already there, and this is a great DIY project for someone who doesn’t mind working up a sweat.”
Project step-by-step (6)
Seal attic bypasses
Seal air leaks
Pull back the existing insulation and use expanding spray foam (the fire-blocking type) to seal any gaps around plumbing pipes, ceiling perforations and holes where electrical wires snake through. “Make sure to seal all the way around the pipe,” says Olson. For gaps 1/4 in. or less, use caulk (the fire-blocking type) rather than expanding foam. Leaks from cracks and gaps around lights, plumbing pipes, chimneys, walls and other ceiling penetrations are the equivalent of having a 2-ft.-wide hole in your ceiling. The worst offenders are open stud and joist cavities and dropped soffits and ceilings in kitchens and baths (see Photo 1).
Install or repair vent chutes
Pull the existing insulation away from the roof. Position the new vent chute so the bottom extends 6 in. into the overhang and staple it into place. Olson suggests using a squeeze stapler instead of a hammer stapler. “It’s more accurate and there’s less chance you’ll crumple the chute.”
“In 95 percent of the homes we work on, the vent chutes are missing or aren’t properly installed,” says Olson. Without them, you’re not getting the most out of your insulation’s R-value because air needs to move properly at the eaves to remove moisture in the winter and heat in the summer.
To make sure existing chutes aren’t blocked, stand in a dark attic to see whether light from the eaves is filtering through the vents. Replace any chutes that are blocked, damaged or missing. You’ll find both plastic and foam vent chutes at home centers. Olson recommends using foam chutes. “They’re more rigid and there’s less chance of them getting crumpled or compressed when you’re installing them.” Pull back the existing insulation so you can see out to the edge of the eaves, and install a vent chute in every rafter space (Photo 2).