As the title indicates, this insulation is blown into the space that needs to be insulated. You can do it without blowing equipment but at a much lower coverage rate per bag. Some places that sell blown insulation will include a free equipment rental with a certain minimum amount of bags. But even if you have to pay for the Insulation Blower rental, the cost is more than likely recovered by the more extensive coverage per bag.
To estimate this product, you will need to know how much one bag covers (cubic foot value), the R-value of the material per 1 inch of coverage (settled), your total required R-value and the square footage of the area.
On the packaging, there will be a coverage chart showing the minimum applied and settled thickness required to meet the "Thermal Resistance," the required R-value. (average value = R 3.6 per inch). Area coverage values per bag are dependent on the package size.
Length = 10 ft--width = 6 feet--bag coverage= 16.5 cubic ft--R value per 1" = 3.6--required R val. = 12 Area = 10 * 6 = 60 square ft Required depth to achieve R value needed = R 12 / R 3.6 = 3.3 inches Volume needed = 60sq ft * 0.275 (3.3 /12 converting to decimal ft) = 16.5 cubic feet You would need one bag in this case.
Note: The cost is based on rounding up the number of bags needed. In some of the calculations, this will be a very small amount, and you should be able to make do with one less bag.