Superinsulating the Attic: An easy way to improve home energy efficiency

One of the easiest ways to dramatically improve energy efficiency in an older home is to insulate the attic.  It’s a job that takes an insulation professional only a couple of hours to do, and besides the benefit of saving energy over time, it immediately makes the home more comfortable.  And quiet!!

Inches and R Value

Inches & R

Since heat rises, attic insulation is far more important than wall insulation.  Typically, most houses in American today have 3 to 6 inches of insulation in the attic.  This translates to an insulation value of about R-10 to R-15.  Adding enough insulation to make the attic “superinsulated” (14 inches of insulation for R-38 value, to 22 inches of insulation for R-60 value) typically costs around $1 per square foot.  Our recent project of adding R-30 cost less than $1000, and for this investment we expect a payback in 2 to 3 years.  We chose to finance the project through our account with the gas utility, so that if we were to move the next residents would take over the payments on the investment along with being able to reap the energy savings benefits.  According to an Energy Star study, the typical American house could use as much as 20% less energy for heating and cooling after some relatively inexpensive and easy improvements.  This typically means a 10% reduction in total house energy use.  These improvements include sealing common types of air leaks around the house as well as adding R-23 of attic insulation and insulating the floor over crawl spaces.

R10 Attic Insulation

Spraying fiberglass into an attic which had less than 4 inches of insulation (approx R-10)

Above and below are the BEFORE and AFTER shots of our recent attic insulation project.  We hired the job out, and were very glad we did!  The professionals have access to better equipment and have the experience to be able to spread the insulation around evenly.  The new fiberglass matterial feels like synthetic cotton balls.

Superinsulated Attic

An attic newly superinsulated with fiberglass insulation (R-40+)

Our recent project included adding ventilation baffles to ensure good air flow in the attic.  The final step was sealing and insulating the attic access hatch.  Our attic hatch is a square peice of sheet rock.  It was sealed by putting a rubber weather-strip around the perimeter.  For insulation, the access hatch was just surrounded by strips of insulation batts, and then one batt laid across the top.

We have been appreciating the quiet and comfort of having a superinsulated attic.  Now we wish we had done this sooner!