The amount of insulation you need will vary depending on where you live. Energy Star recommends certain minimum insulation values in different geographic regions. In most cases, however, even adding a little insulation is better than not adding any.

Asphalt roofs provide better insulation than metal roofs, but that doesn’t always mean that asphalt roofs are better for reducing heating and cooling bills. In hotter climates, metal roofs will usually be better for home efficiency because the material reflects more sunlight and reduces solar heat gain. In colder climates, asphalt roofs are sometimes superior in terms of efficiency because they introduce more solar heat gain to your home and have greater insulating capabilities. However, metal roofs installed with an air gap can provide similar levels of insulation.

The cost of installing spray foam insulation is $2,760 on average, but this cost can be as low as $650 or as high as $7,700. The main cost factor is the size of the insulated area and the type of spray foam insulation. 

Polyurethane spray foam costs between $0.44 and $1.50 per board foot, where a board foot is equal to the volume of a one-foot length of a board. More expensive options, like soybean or vegetable oil spray foam, range from $1.50 to $3.00 per board foot.

On average, insulating an attic costs about $2,500, with a typical range of $1,500 to $3,500. The final price often depends on the attic's size, with costs generally falling between $1 to $3 per square foot. For example, insulating a 1,800-square-foot attic would likely cost between $1,800 and $5,400.

If the project involves removing old insulation, this can add an average of $900 to the total cost, bringing a full removal and reinsulation project to around $3,000.

Several factors influence the overall cost:

• Insulation Type: Prices per square foot vary significantly by material.

• Reflective: $0.50–$1.50

• Blown-in: $1–$4

• Batt: $2–$4

• Loose-fill: $2–$5

• Spray foam: $2–$5

• Structural insulated panels (SIPs): $4–$7

• Project Complexity: Factors like sealing air leaks, poor attic accessibility, and required inspections can add to the cost.

• Removal Issues: The discovery of mold, asbestos, or pests during the removal of old insulation can substantially increase the price.