How Much Does It Cost to Add Attic Insulation? Types, Calculator & DIY Guide

Adding insulation to your attic is one of the most cost-effective ways to improve your home's energy efficiency. A properly insulated attic can reduce heat loss in winter and heat gain in summer. This results in lower utility bills, greater comfort indoors, and reduced environmental impact.

In this comprehensive guide, we'll cover everything you need to know about installing new attic insulation or adding more to your existing insulation.

How Much Does Attic Insulation Cost?

Several factors affect the overall cost of attic insulation:

• Type of insulation material – Fiberglass batts are the most affordable option, while spray foam is more expensive up-front.
• Installation method – DIY insulation costs less in materials, but hiring a professional may provide longer-term benefits.
• Attic size – The larger your attic area, the more insulation is required.

Insulation is priced per square foot based on materials and labor. Here are typical costs:

• Fiberglass batt insulation: $0.75–$1 per square foot DIY, $1.50–$2 installed professionally
• Blown-in cellulose: $1–$1.25 per square foot DIY, $2–$2.50 installed professionally
• Spray foam insulation: $3–$7 per square foot installed professionally

For a 1,500-square-foot attic, expect to spend around $1,500 to add cellulose insulation professionally. DIY fiberglass installation may cost $500–$750 in materials.

Get multiple quotes when hiring an insulation company. Prices vary based on labor rates, materials, and any specials/rebates offered. Some contractors may charge extra for attic inspections, permits, or equipment rentals. Carefully compare complete costs from at least three installers.

What Types of Attic Insulation Are Used?

There are four main types of insulation suitable for attic installation:

Fiberglass Batt Insulation

Fiberglass insulation consists of thin batts or rolls of spun fiberglass. It's an affordable option available at home improvement stores but requires more labor to install properly than blown-in insulation.

Fiberglass batts are fitted between attic trusses, rafters, and studs. The batts should fill cavities with no gaps and be secured to prevent sagging. Hiring a pro to neatly tuck batts is recommended.

Blown-in Cellulose Insulation

Blown-in cellulose is made from recycled materials and can fill attic spaces. Cellulose has a high R-value per inch compared to fiberglass. Installing it usually requires professional equipment.

Dense-packed cellulose is ideal for attics. The dense consistency fills every nook, prevents settling, and provides excellent air sealing. Cellulose is treated with fire retardants for safety.

Loose-Fill Fiberglass

Loose-fill fiberglass is similar to cellulose but made from spun fiberglass. It's an affordable DIY option but doesn't insulate as efficiently per inch as cellulose.

Loose-fill fiberglass is blown into attics. It can settle over time, creating gaps that reduce effectiveness. Using professional equipment is recommended to achieve proper density.

Spray Foam Insulation

Spray foam insulation is applied by professionals using special equipment to spray and expand rigid polyurethane foam. Foam insulation adheres well to surfaces and seals cracks. It's more expensive than other types but has a very high R-value.

Open and closed-cell spray foam minimizes attic air leaks when applied correctly. Closed cells provide a higher R-value, while open-cells are more affordable. Spray foam suits challenging attic spaces.

How To Calculate How Much Insulation You Need

The insulation recommended for your attic depends on your climate zone, framing method, and attic ventilation. To determine how much you need:

1. Find your climate zone – The Department of Energy provides climate zone maps. Zones 6 and 7 have the highest recommendations.
2. Determine the exposed attic surface area – Measure length x width for floor area, then add sloped regions.
3. Identify the recommended R-value for your zone – Typically R-30 to R-60.
4. Divide the recommended R-value by the R-value per inch of your insulation type.

For example, Zone 6 recommends R-49. For a 1,000-square-foot attic using cellulose (R-3.7/inch), you'd need 49/3.7 = 13 inches of insulation.

Free online calculators also simplify this process. The Department of Energy provides an insulation R-value map and an easy calculator.

When determining the R-value needed, account for existing insulation. Measure current depth and type in each attic section to calculate existing R-value, then choose additional insulation required to meet recommendations.

DIY vs. Professional Attic Insulation

You can save money by installing batt or loose-fill fiberglass insulation yourself. However, hiring professionals offers benefits like:

• Precise installation to fill attic cavities.
• Access to dense-pack cellulose with higher R-values.
• Ability to identify gaps, leaks, moisture issues, and other problems.
• Improved energy efficiency from quality installation.
• Time savings from not having to rent equipment and install insulation.
• Peace of mind from warranties provided.

The small DIY savings are often outweighed by using professional installers. Many companies also offer rebates, financing, and guarantees.

If DIY, research proper installation techniques thoroughly. Wear appropriate safety gear and rent equipment as needed. Poor insulation work can leave costly gaps and air leaks.

What Are the Top Attic Insulation Brands?

Look for attic insulation certified by the National Green Building Standard, such as:

• Owens Corning – Offers EcoTouch fiberglass and PureSafety cellulose made from 85% recycled materials.
• Johns Manville – Spider Plus blown-in fiberglass uses formaldehyde-free binders.
• Knauf Insulation – Provides ECOSE fiberglass and EcoBatt insulation with bio-based binders.
• CertainTeed – Certified InsulSafe spray foam and CertaPro batts are formaldehyde-free.

Always confirm insulation meets building codes. Reputable brands undergo extensive quality testing.

Learn More About Attic Insulation

So, Is Attic Insulation Worth It?

For most homes, adding attic insulation is a wise investment. The energy savings from a well-insulated attic typically pay for costs within a few years. It's one of the most cost-effective ways to reduce utility bills and improve living space comfort.

Before installing insulation, address any attic air leaks, moisture issues, or inadequate ventilation. Determine the right insulation R-value and type for your climate and attic layout. While DIY is possible, hiring professionals help ensure you fully realize the benefits of a properly insulated, sealed attic.