Spray Foam Insulation R Value Vs Fiberglass

For instance a 5 5 inch wall cavity can be filled with 2 inches of foam and an r 13 fiberglass batt as a cost effective system that seals the walls with an r 25 insulation system exceeding u s.

Spray foam insulation r value vs fiberglass.

Once applied closed cell foams become rigid and have an r value range from r 6 to r 7. The common denominator among varieties of insulation is the r value. Home improvement stores will often rent you a machine to blow in the fiberglass. Spray foam insulation vs fiberglass r value is about equal for open cell insulation and about double for closed cell insulation per one inch layer.

The r value of spray foam insulation is approximately 6 per inch so those using spray foam as their insulator will need about 6 3 inches of thickness to reach r 38. Fiberglass insulation is less than half the price of rigid foam insulation when calculated by r value per square foot. Considering diy blown fiberglass insulation vs spray foam both require care to get the thickness right. The r value is a measurement of how resistant the product is to heat flow the higher the r value the more heat will be prevented from transitioning through the insulation.

A spray foam rig can cost upwards of 70 000. Available spray foam types include cementitious phenolic polyisocyanurate polyiso and. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. If you are dealing with a residential home then most likely you will be attempting to reach an r value of 38 meaning with the r value of spray foam being about 6 per.

Open cell foam is soft and spongy impermeable to air but permeable to moisture and according to the doe has an r value per inch ranging from r 3 6 to r 4 3. Compare spray foam vs fiberglass insulation costs summary. Average cost of spray foam vs fiberglass insulation one board foot 12 x 12 x 1 of open cell foam insulation averages 0 45 to 0 80 cents the same amount of closed cell insulation costs between 1 and 2 a square foot of fiberglass costs between 1 30 and 3 50 on average. These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation.

For example insulating a 10 square foot wall area to r 15 costs about 3 40 to 4 00 with fiberglass insulation while a comparable r value for rigid foam costs roughly 10. The r value of fiberglass insulation is approximately 2 2 per inch so much thicker fiberglass insulation is required to achieve the same r value of 38. 1 additionally spray foam insulation has a high cost of entry with required training and equipment. The installed cost for r13 of spray foam insulation has been shown to be nearly 3 4 times as much for the same r value as fiberglass.