Blown Insulation Calculator provides an accurate price estimate based on your home size, amount of insulation (R-Value), wall depth, and part of the house which you need to insulate.
Estimate Blown-in Insulation Cost in CA
R-VALUE * For code minimum, we use 38R for colder states, and 30R for warmer states in the attic. For maximum R-Value, we use 60R for colder states and 49R for warmer states in the attic. Our calculator will update the price estimate based on the desired R-Value option that you select.
Per manufacturers specifications, we use 3.7R value per inch of Cellulose insulation, and 2.9R per inch of Fiberglass insulation. If you chose “Custom R-Value” for attic insulation, your input should is in “R”, not in insulation thickness. If you need a specific thickness of insulation, multiply inches by respective R value of your desired insulation type.
PATCHING (FINISHING) WALLS ** Blown in insulation in walls requires cutting round holes 2-3″ wide between each rafter. Usually this is done inside the house, by cutting holes in the drywall.
In certain cases, if for example, you have lath & horse-hair wall plastering, cutting holes inside is not feasible, without causing lots of wall damage.
In such cases, contractors my cut holes in the outside wall, by lifting vinyl siding, or cutting into wood siding.
Some homeowners choose to have these holes patched themselves, or by hiring a plastering / drywall contractor, to do the work.
In other cases, your insulation contractor can plug the holes, at an extra cost. Our calculator will update the price estimate based on the option you select.
How To Get An Accurate Blown In Insulation Quote
This calculator is pretty straight forward – resulting price quote is based on your inputs, and your geographic location.
Based on the state you are in, local cost of living is factored into the price quote, as well as Code Minimum R-Value requirement for attic insulation.
1) Home Size: Enter your house dimensions.
2) Insulation Type: Select Cellulose of Fiberglass.
3) Areas to Insulate: Select if you need to insulated Attic + Exterior Walls (default option), Attic Only or Walls Only.
Depending on the option you selected in step 3, you will see additional options. If you selected “Attic + Walls” or “Walls Only”, you will see the following options, that correspond to either Attic or Exterior Walls or both:
4a) Number of Floors: Select how many floors/levels your house has. Only available if “Attic + Walls” or “Walls Only” is selected in Step 3.
4b) Attic R-Value: Choose insulating / R-Value that you are looking for – Code Minimum (30R or 38R depending on your state) or custom R-Value. See more information above. Only available if “Attic + Walls” or “Attic Only” is selected in Step 3.
4c) Patching Walls: Choose who will be doing wall patching, after insulation is installed. Only available if “Attic + Walls” or “Attic Only” is selected in Step 3.
“Contractor” option means that insulation contractor will also do the patch work. This will add extra charge to the price quote.
“Homeowner” option means that either you or your outside drywall/plastering contractor or a handyman that you hire separately, will do this part of the job.
4d) Wall Stud Size: Select wall stud depth – this will determine how much materials are needed to insulate your exterior walls. Only available if “Attic + Walls” or “Wall Only” is selected in Step 3.
How Much Does Blown In Insulation Cost
Insulating your home with Blown-in insulation is the most cost-efficient method to gain maximum R-value and can reduce your energy costs by as much as 20-30%! Blown-in insulation, is pretty much the only option to insulate walls in a finished home.
Typical cost of adding insulation on your Walls and Attic ranges from $3,240 to $5,260, for a 2000 sq. ft. home which includes 13R in the walls and 38R in the attic, using Cellulose Fiber insulation. Fiberglass insulation would be additional $750-900.
First let’s begin with walls:
1 sq. ft. of Cellulose insulation installed in a 2×4 wall cavity costs on average $0.90 – $1.10 installed.
1 sq. ft. of Fiberglass insulation installed in a 2×4 wall cavity costs on average $1.00 – $1.20 installed.
1 sq. ft. of Closed Cell Spray Foam insulation costs on average $2.20 – $3.10 installed.
Next, let’s look at attic / ceiling insulation – here we provide price per 1 sq. ft. of 60-R insulation, which varies in thickness, depending on material.
1 sq. ft. of Cellulose insulation in attic (16.2″ thickness) costs on average $2.10 – $2.40 installed.
1 sq. ft. of Fiberglass insulation in attic (20.7″ thickness) costs on average $2.80 – $3.20 installed.
1 sq. ft. of Closed Cell Spray Foam insulation in attic (8.5″ thickness) costs on average $5.80 – $6.90 installed.
As you can see, to achieve 60R value, it costs about $2.25 per square foot of Cellulose, and about $6.40 per square foot of Spray Foam. This is nearly a 3x difference in price!
How Much Does Blown In insulation Cost Per Square Foot?
Which Blown In Insulation Is Better – Fiberglass vs Cellulose?
It’s not that easy to answer this question as both types have their own advantages and disadvantages. However, for the most part, Cellulose fiber insulation is Cheaper and has Higher/Better Insulating R-Value than Fiberglass.
Material cost per Sq. Ft. of Cellulose is about 25% less than Fiberglass. However, when you look at a big picture, difference is only about $0.015 per one inch of thickness! If you have a 2000 sq. ft. house, the total difference is about $750-900.
What is more important, is a 20 higher insulation value of a cellulose fiber. In a 2×4 wall, you wall cavity, you will get 13R with cellulose and only about 10R with Fiberglass.
Another benefit of Cellulose, is it’s Fire Resistance (when properly treated by the manufacturer with Ammonium-Sulfate & Borate fire retardant). Treated cellulose will not burn, when source of flame is removed, as can be seen in the video below:
At the same time, fiberglass blown-in insulation will melt, but not burn. However, melting will allow open flame to reach the wooden framing.
With everything mentioned above, you may ask – what is the benefit of Fiberglass, and why should you pay more for it. Main benefit of fiberglass insulation is when it gets wet, it can actually be dried, whereas cellulose will stay wet for a very long time, and start growing mold.
Second benefit of fiberglass, is the fact is that its settling is minimal, compared to cellulose, which is over 10%. This means that cellulose in a wall cavity that is 8′ high (96″) will settle almost 10 inches, UNLESS it is densely packed, which unfortunately, most contractors will not bother with, as it takes a lot more labor, and does not add any profit.
Final disadvantage of cellulose (and advantage of fiberglass) is amount of dust in a cellulose information. If you have any sort of respiratory issues, then cellulose insulation is likely not a good choice for you.
Is Blown In Insulation Better Than Spray Foam?
The answer is – it depends. If you are looking for as much R-Value in a limited thickness scenario, nothing beats Closed Cell spray foam, which has nearly double the insulation value of cellulose or fiberglass.
If you are looking for moisture / vapor resistance, once again, closed cell foam is far superior.
However, when you have an existing home with finished walls, you cannot install spray foam, without removing all the drywall. In such case, blown in insulation is your only option, and is actually a very decent choice, given a fairly good R-Value (up-to 4R per inch when densely packed).
Also, blown in insulation is much cheaper than spray foam per 1 sq. ft, and per R-Value. In fact, blown in insulation is about 45-60% cheaper than closed cell foam.
Insulating Whole House (walls + attic) VS Attic Only
This calculator is designed to only estimate the cost of Blown In insulation, which adds certain limitation to the actual installation process. Blown in insulation CANNOT be installed between roof rafters, as it will simply fall down.
When in comes to insulating walls in a finished home, blown in insulation is the ideal product, because in can be inserted inside the wall cavity through a small plug hole, cut in-field by the installer. Other insulation products are not feasible, as they would require removing all the drywall.
However, if you only need to insulate the attic OR if your house is completely gutted / new construction, you now have many other options, such as Spray Foam, fiberglass batt/rolled insulation, as well as blown-in.
For attic insulation only projects, you can use other materials, and we have a dedicated Attic Insulation Calculator, which gives you many more options, that just blown-in type.
Can You Get Rebates / Tax Credits When Installing New Insulation?
Depending on the state you live in, you can get as much as 75% of your installation cost covered by local energy efficiency programs/agencies, and in certain cases even get a home efficiency tax credit (consult with your CPA about tax credits).
In Massachusetts for example, our MassSave program will pay for 75% of total installation cost of your insulation project.
However, in most cases it only covers Cellulose blown in product installed by an approved contractor, in “standard application” scenario. Still this actually applies to most homes with no or some insulation.
Also these approved contractors actually charge reasonable rates, set by the state.
Check out the energy savings programs in your state to see if you qualify for any rebates.