Step One – Calculate Your Need

Step One – Calculate Your Need


Calculate How Much GreenFiber Insulation You Need

First, determine the R-value recommended for your region. R-value indicates insulating power or thermal resistance (chart at left). Once you know your target R-value, refer to the GreenFiber Insulation coverage chart (on GreenFiber Insulation product bag or see charts below). This chart will indicate, for a 1,000-square-foot area, how many bags of GreenFiber Insulation you will need to purchase and how many inches of coverage you will need.

To calculate exactly how much GreenFiber Insulation you need for a specific number of square feet, you can use the following table provided by the U.S. Department of Energy Insulation Recommendations for Existing Houses.*

This is GreenFiber® Cellulose Loose-Fill Insulation
click here to download coverage chart in PDF

Application Coverage Chart Product # INS541LD
R-Value @75°F Mean Temp Minimum Thickness
Maximum Net Coverage
(No Adjustments for Framing)
Gross Coverage
(Based on 2″x6″ Framing, 16″ on centers)
To Obtain a Thermal Resistance (R) of: Installed Insulation Should Not Be Less Than Thickness After Settling Maximum Square Feet per Bag Minimum Bags per 1,000 Square Feet Minimum Weight (lbs.) per Square Foot Maximum Square Feet per Bag Minimum Bags per 1,000 Square Feet
R-13 4.29 3.86 56.0 17.9 0.340 61.8 16.2
R-19 6.19 5.57 36.7 27.2 0.519 40.0 25.0
R-22 7.12 6.41 31.1 32.2 0.613 33.5 29.8
R-25 8.05 7.25 26.8 37.2 0.710 28.7 34.9
R-30 9.57 8.62 21.7 46.1 0.878 22.9 43.6
R-38 11.97 10.77 16.4 61.1 1.164 17.1 58.5
R-49 15.20 13.68 12.0 83.5 1.591 12.4 80.7
R-60 18.37 16.53 9.3 108.1 2.059 9.5 105.0

Sample Calculation for 1,000 Sq. Ft. Attic

Sq. Ft.
/  Sq. Ft/Bag
From Chart
=  Number of
Bags Required
40 Sq. Ft. Bag
1,000 Sq. Ft. /  40 Sq. Ft. Bag =  25 Bags
Your Calculation

Read This Before You Buy

What you should know about R-values

This chart shows the R-value of this insulation. R means resistance to heat flow. The higher the R-value, the greater the insulating power. Compare insulation R-values before you buy. There are other factors to consider. The amount of the insulation you need depends on the climate you live in. Also, your fuel savings from insulation will depend upon the climate, the type and size of your house, the amount of insulation already in your house, and your fuel use patterns and family size. If you buy too much insulation, it will cost you more than what you’ll save on fuel. To get the marked R-value, it is essential that this insulation be installed properly.

To determine the amount of existing insulation you have, refer to the following chart from the Department of Energy found on their web site,

The Above Coverage Chart Is Based On A Nominal Bag Weight Of 19.05 Lbs Using The Greenfiber Monarch Blowing Machine. Settings Are Not Adjustable. The Chart Is Based On Settled Thickness And Is For Estimating Purposes Only. Do Not Exceed Maximum Square Feet Coverage Per Bag. The Applicator Must Install Both The Minimum Number Of Bags Per 1000 Sq. Ft. And The Minimum Installed Thickness To Insure The Stated R-Value Has Been Reached. Failure To Meet Both These Requirements May Prevent The Application Of Specified R-Value. This Product Must Be Installed Dry. This Coverage Chart Does Not Apply To Floor Applications. Do Not Add Water To This Product. Job Conditions, Application Techniques, Equipment, And Settings Can Influence Actual Coverage. Minimum Net Weight Is 18.1 Lbs.