Blow in Insulation Calculator for Attic

FAQs

How do I calculate blown-in insulation for my attic?

To calculate the amount of blown-in insulation needed for your attic, you’ll need to determine the desired R-value and the attic’s square footage. The formula is:

Total insulation needed (in cubic feet) = Attic square footage (in square feet) * Desired R-value (in inches)

For example, if your attic is 1,000 square feet and you want an R-value of R30:

Total insulation needed = 1,000 sq ft * 30/12 inches = 2,500 cubic feet

How many square feet does one bag of blown-in insulation cover?

A standard bag of blown-in insulation typically covers approximately 50-55 square feet at a depth of R30.

How many bags of blown-in insulation do I need for 1,000 sq ft?

If you want to achieve an R-value of R30 in a 1,000 square foot attic, you would need approximately 18-20 bags of blown-in insulation.

Can you put too much blown-in insulation in your attic?

Yes, you can over-insulate your attic. While more insulation can improve energy efficiency, there is a point of diminishing returns. Excessive insulation can lead to issues such as moisture problems and decreased ventilation. It’s important to follow local building codes and guidelines for insulation levels.

How many inches of blown-in insulation is R30?

R30 insulation is typically achieved with approximately 10 inches of blown-in insulation.

Is blown-in attic insulation worth it?

Blown-in attic insulation can be worth it as it provides good coverage and is effective in improving energy efficiency and reducing heating and cooling costs. However, its worth depends on your specific needs, budget, and the condition of your attic. It’s often a cost-effective way to upgrade insulation.

How deep is R60 blown-in insulation?

R60 insulation usually requires about 20 inches of blown-in insulation to achieve the desired level of thermal resistance.

How long does it take to blow in 1,000 square feet of insulation?

The time it takes to blow in insulation for 1,000 square feet can vary depending on the equipment used and the experience of the installer. A professional contractor with the right equipment might be able to complete the job in a few hours.

How much does it cost to blow in insulation in 1,000 square feet?

The cost of blowing in insulation can vary based on factors like insulation type, local labor rates, and insulation depth. As a rough estimate, you might expect to pay anywhere from $1,000 to $3,000 for a 1,000 square foot attic, but prices can vary significantly.

How long does it take to blow in a bag of insulation?

Blowing in a bag of insulation can take a few minutes to load into the equipment and then a few minutes to actually blow into the attic, depending on the equipment’s capacity and efficiency.

How thick should blown-in insulation be?

The thickness of blown-in insulation should be determined by the desired R-value and the type of insulation used. For example, R30 insulation typically requires about 10 inches of blown-in insulation.

How many square feet is a bag of R30 insulation?

A bag of R30 blown-in insulation typically covers around 50-55 square feet when installed at the recommended depth.

What is a good R-value for an attic?

A good R-value for an attic depends on your climate and local building codes. In many regions, an R-value of R38 to R60 is recommended for attics to achieve adequate insulation.

What is the R-value of 12 inches of blown insulation?

12 inches of blown insulation typically corresponds to an R-value of approximately R38 to R40, depending on the type and density of the insulation.

Is fiberglass or cellulose insulation better?

Both fiberglass and cellulose insulation have their advantages and disadvantages. Fiberglass is fire-resistant and doesn’t settle over time, but cellulose can be more environmentally friendly. The choice depends on your priorities and budget.

What is the R-value of 14 inches of blown insulation?

14 inches of blown insulation typically corresponds to an R-value of approximately R44 to R48, depending on the type and density of the insulation.

What are the disadvantages of blown-in insulation?

Disadvantages of blown-in insulation can include settling over time, difficulty in achieving uniform coverage, and potential issues with moisture if not properly installed or if the attic has ventilation problems.

How often should blown-in attic insulation be replaced?

Blown-in attic insulation can last for decades if properly installed and maintained. There is typically no need to replace it unless it becomes damaged or contaminated.

Should I remove old attic insulation before adding new?

In many cases, it’s not necessary to remove old attic insulation before adding new insulation. However, it’s important to assess the condition of the existing insulation and consult with a professional to determine the best course of action.

What is the best insulation for an attic ceiling?

The best insulation for an attic ceiling depends on factors like budget, climate, and personal preferences. Common choices include blown-in insulation, fiberglass batts, and spray foam insulation.

Does R30 and R38 make a difference?

Yes, R30 and R38 make a difference in terms of insulation effectiveness. R38 offers better thermal resistance and is more efficient at retaining heat than R30.

What is the difference between R38 and R49?

The primary difference between R38 and R49 is the level of thermal resistance they provide. R49 has a higher R-value and provides better insulation than R38.

Do I need a vapor barrier with blown-in attic insulation?

In some cases, a vapor barrier may be necessary with blown-in attic insulation, especially in climates with high humidity. It helps prevent moisture from entering the insulation and causing problems. Consult local building codes and a professional for guidance.

Is a spray foam attic better than blown-in insulation?

Spray foam insulation can offer superior air sealing and insulation properties, but it’s generally more expensive than blown-in insulation. The choice depends on your budget and specific insulation goals.

Which is better attic insulation, blown or rolled?

Both blown and rolled (batt) insulation can be effective in attics, but the choice depends on factors like insulation type, budget, and installation preferences. Blown insulation is often chosen for its ability to fill irregular spaces more effectively.

Is R60 too much insulation?

R60 insulation is not too much if it’s properly installed and doesn’t cause ventilation or moisture issues. It can result in excellent energy efficiency, especially in colder climates.

What is the smallest hole for blown-in insulation?

The size of the hole for blown-in insulation typically depends on the equipment used but is generally small, around 2 inches in diameter or less.

Is R30 better than R60?

R60 is better than R30 in terms of insulation performance and energy efficiency. However, the choice depends on your climate, budget, and specific insulation goals.

Can I blow in insulation myself?

Blowing in insulation can be a DIY project, but it requires the right equipment and safety precautions. If you’re not experienced, it’s often best to hire a professional.

How many bags of blown-in insulation do I need?

The number of bags of blown-in insulation you need depends on your attic’s square footage, desired R-value, and the coverage area per bag. As a rough estimate, you might need 18-20 bags for a 1,000 square foot attic with an R30 target.

Can you walk through blown-in insulation?

You can walk through blown-in insulation, but it’s not recommended as it can compress the insulation, reducing its effectiveness. If you need to access your attic frequently, consider installing attic flooring.

Is blown-in insulation cheaper than spray foam?

Blown-in insulation is generally cheaper than spray foam insulation, making it a cost-effective option for many homeowners.

Is it cheaper to blow in insulation or use batts?

Blowing in insulation is often more cost-effective than using batts because it can provide better coverage and fill irregular spaces more efficiently.

Is blown-in insulation cheaper than batts?

Blown-in insulation can be cheaper than batts on a per-square-foot basis, but costs can vary depending on factors like insulation type and installation complexity.

What to do before blowing insulation?

Before blowing in insulation, you should inspect your attic for any issues like leaks, mold, or ventilation problems. Ensure that any necessary repairs are completed before insulation installation.

Is too much blown-in insulation bad?

Excessive blown-in insulation can lead to problems like reduced ventilation and potential moisture issues. It’s important to follow recommended insulation levels for your climate.

How messy is blown-in insulation?

Blown-in insulation can create a mess during installation, but professionals typically take precautions to minimize mess and clean up afterward.

Should I insulate my attic floor or ceiling?

Attic insulation is typically installed on the attic floor to separate the conditioned space from the unconditioned attic. Insulating the attic floor is more common and efficient for maintaining indoor comfort.

Should I use faced or unfaced insulation for attic ceiling?

The choice between faced (with a vapor barrier) or unfaced insulation for the attic ceiling depends on your climate and whether you need to control moisture. Faced insulation is generally better for cold climates to prevent moisture issues.

Should I use R30 or R38 in my attic?

The choice between R30 and R38 depends on your specific insulation needs and budget. R38 provides better insulation but may not always be necessary depending on your climate.

Is R49 better than R38?

R49 offers better insulation and thermal resistance compared to R38, making it a more efficient choice for improving energy efficiency.

How many inches of insulation do I need for R49?

To achieve an R49 rating, you would typically need approximately 16-17 inches of insulation, but this can vary depending on the type and density of the insulation.

How deep is R49 blown-in insulation?

R49 blown-in insulation usually requires about 16-17 inches of insulation depth to achieve the desired R-value.

Should there be a gap in the attic with the insulation?

Attic insulation should be continuous without gaps to provide effective thermal resistance. Gaps can allow heat loss or heat gain.

Which side does the vapor barrier go on in the attic?

In most cases, the vapor barrier should be placed on the warm side of the insulation, which is typically the attic floor (ceiling below the attic). This helps prevent moisture from entering the insulation from the conditioned space below.

Is there a downside to spray foam insulation?

One downside of spray foam insulation is its higher cost compared to other insulation types. It also requires professional installation due to the specialized equipment and materials used.

What are the disadvantages of spray foam roof insulation?

Disadvantages of spray foam roof insulation can include the potential for moisture issues if not installed correctly, difficulty in detecting roof leaks, and the need for professional installation.

What is the most effective attic insulation?

The most effective attic insulation depends on various factors, but spray foam insulation is often considered one of the most efficient options due to its air-sealing properties and high R-value per inch.

How many inches of insulation do I need for R60?

To achieve an R60 rating, you would typically need approximately 20 inches of insulation, but this can vary depending on the type and density of the insulation.

Do small gaps in insulation matter?

Small gaps in insulation can reduce its effectiveness and lead to energy loss. It’s important to properly seal and insulate all gaps and openings to maximize energy efficiency.

Is blown-in cellulose better than blown-in fiberglass?

Blown-in cellulose and blown-in fiberglass both have their advantages. Cellulose is often considered more environmentally friendly, while fiberglass is fire-resistant. The choice depends on your priorities.

Is R60 attic insulation worth it?

R60 attic insulation can be worth it in colder climates where energy efficiency is a priority. It can significantly reduce heating and cooling costs over time.

How many inches thick is R60?

R60 insulation typically requires about 20 inches of insulation thickness to achieve the desired R-value.

Is it OK to blow insulation over old insulation?

It’s generally okay to blow new insulation over old insulation, but it’s important to assess the condition of the existing insulation and ensure it’s not contaminated or damaged.

How much does 10 bags of insulation cover?

The coverage of 10 bags of insulation depends on the insulation type and thickness. As a rough estimate, 10 bags may cover approximately 500-550 square feet at a depth of R30.

Does blown-in insulation need a vapor barrier?

Blown-in insulation may or may not require a vapor barrier, depending on your climate and the type of insulation used. Consult local building codes and a professional for guidance.

How messy is blown-in insulation?

Blown-in insulation can create some mess during installation, but professionals take precautions to minimize mess and clean up afterward.