Filling an attic, the walls, or flooring with blown-in insulation is a great way to save on your heating bill, and makes a home or room FAR more comfortable. Overall, most people report it’s a big improvement and provides heating in the winter, and cooling in the summer. But, how do you know how much blown-in insulation you need, here’s how to calculate it.
In general, find what zone you live in, and what R value insulation it means you need. Then find the total square feet of the area you are applying blown-in insulation into. After that use the formula below, which will tell you how many lbs of blown-in insulation you need.
A higher R value means the blow-in insulation you get will provide more insulation. But, there is a maximum R value for insulation, R60 if very popular because it’s the maximum a home should get in most zones. Below is the table and full breakdown of how to calculate the cost of blown-in insulation whether you’re installing it over existing installation, improving the insulation of your attic, or blowing it behind walls.
Blown in Insulation Calculator Estimator / Calculator
Blown-in insulation is a great way to increase the comfort of a room or home, as well as save on the amount of heating, cooling, and air conditioning you need to use. It’s recommended to get an idea of all the costs involved to install blown insulation, so here’s a summary of how to know what type of blown-in insulation to get, and how much you will need based on where you’re blowing it.
As a general rule, first find the area of the space you are filling with blown-in insulation by measuring the width and the length. Then find what zone you are in and what R value this means your insulation needs to have. After that, use the steps below.
After you know how much blown in insulation you need, you should shop around Walmart, Lowe’s, Amazon, and places like these to get an idea how much their blown in insulation is per bag. It can vary for example, and Lowe’s they are as cheap as $15 per bag for fiberglass blown-in insulation, which is the best.
1. Find the Zone Your House is in
Here’s a table that shows what the R value is of the insulation you need based on what State you live in:
| Zone (refer here to find you zone) | Adding insulation an attic |
| Zone 1 | 30 to 49 (R30 to R39) |
| Zone 2 | 30 to 60 (R30 to R60) |
| Zone 3 | 30 to 60 (R30 to R60) |
| Zone 4 | 38 to 60 (R30 to R60) |
| Zone 5 to 8 | 49 to 60 (R49 to R60) |
Zones in the northern States are zones 7 and 8. Whereas, States in the South of the USA are zones 1 and 2. Refer to this color coded map where it tells you what zone you are in.
2. Calculate the amount in lbs of blown-in insulation
Then use the table above to find the R value for your zone. Use that info to work out how much blown in insulation you need.
But, first calculate the square feet of the area you are applying the blown-in into. Use the formula width multiplied by length to get the area in square feet.
| Zone | Adding insulation an attic | Per square foot |
| Zone 1 | 30 to 49 (R30 to R39) |
|
| Zone 2 | 30 to 60 (R30 to R60) |
|
| Zone 3 | 30 to 60 (R30 to R60) |
|
| Zone 4 | 38 to 60 (R30 to R60) |
|
| Zone 5 to 8 | 49 to 60 (R49 to R60) |
|
As you can see from the table, R60 is the maximum R value a blown in insulation should have for almost every zone. Therefore, it is very easy to find in stores, and is reasonably cheap. Typical ranges are about $500 for everything.
Including a contractor to install it. But, labor costs can vary, and unless you shop around, you could do a whole attic for about $1000 by a contractor.
How To Calculate How Much Blown in Insulation Is Needed
Blown-in insulation is sold in bags that are typically 25 lbs. But, to know how many bags you need you need to do a calculation based on the area of your attic, and what zone your home is in. Here is how to calculate how much blown insulation you need for your walls, attic, or floor.
Overall, first calculate the area where you are installing blown-insulation in square feet. Then find out what zone you live in, which will tell you what R value insulation you need. For example R60 is very common and popular. After that do the steps below.
Copyright protected content owner: ReadyToDIY.com and was initially posted on December 27, 2022.
There are two individual steps:
- Calculating the square feet of the area you are putting blown-in insulation
- Finding the zone you live in and the R value for that zone
- Using that info to calculate how much insulation you need in lbs.
Doing so will tell you how many pounds of insulation you need. You then convert it into the number of bags. These steps are explained in detail a bit further up in this article. Refer to the heading that says ‘Step 1. Find the Zone Your House is in’, do the instructions there and then the following step to find out how much insulation you need.
How To Calculate Cost of Blown in Insulation
There are a few additional costs to install blown-in insulation. These include the equipment to install it, and many people opt to have a contractor do it, because the cost of doing so is worth it. Below is how to calculate all the costs of installing blown-in insulation.
In general, first calculate how much insulation you will need based on the area of the space in square feet (length by width). After that find the zone that you live in, and the corresponding R value using the reference table below. Then add that to the cost of hiring the blower, or a contractor.
Installing blown-in insulation is commonly done on old attics that have very poor existing insulation in the roof, and there are a lot of air gaps. Doing so makes a home much more comfortable in winter and summer.
The cost is reduced as well because the IRS will give you a tax credit for the value of $500 because it falls under the (source: Turbo Tax). It falls under the “residential energy property costs” category, and you need to fill an additional form and submit it with your tax return.
How To Calculate Cost of Blown in Insulation Project?
The cost of installing blown-in insulation requires a few things, and varies based on whether you are doing it yourself or getting a contractor to do it. But, here is how to calculate the total cost to install blown-in insulation.
Overall, add the cost of labor/contractor, the cost of the bags of insulation, and the cost to hire the blower. Around $500 to $1000 is reasonable. A contractor is particularly good for an attic, because it’s very dusty, cramped, and awkward to work in most attics. But, will cost $200 to $500.
It’s widely reported that many stores that sell blown in insulation will often rent the blowing machine free of charge. They will also allow you to return any unused insulation. First try Walmart and if they don’t offer this try other similar stores.
However, at the end of the day many people find a cost benefit in having a contractor. Particularly for attics which are difficult to access and work in.
And for people it’s worth it to spend an extra $200 to $500. Especially considering you will often get a rebate on the total project for $500.
Other Things To Consider When Estimating Blown in Insulation Project
Most people have never installed blown-in insulation before, but blown-in insulation has been reported by most people to make a home more comfortable in the winter, and cooler in the summer. So, here’s a rundown of important things to consider when estimating how much an entire blown-in insulation project will be.
In general, blown-in insulation is ideal for existing insulation that is insufficient. But, is ideally suited to an attic or existing space that is impossible or difficult to apply batts. However, it typically requires installing a perimeter around existing insulation to keep the insulation in.
According to Attic Care, a professional insulation and contracting company, the ideal blown-in insulation to get is fiberglass. This has also been backed up by Tony Wojtowicz, a professional home remodeller. As seen in the video below:
Batts are also the ideal insulation to put, and blown-in insulation should only be installed over existing batts, or where you want to add insulation to an area that has already been insulated with batts.
Copyright article owner is ReadyToDiy.com for this article. This post was first published on December 27, 2022.
Overall, first find the R value for the zone you live in, and calculate the square footage of the area you are applying blown-in insulation into. Do that by multiplying the width by the length. After that you can calculate how many lbs of blown-in insulation you need using the formula below.
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ReadyToDIY is the owner of this article. This post was published on December 27, 2022.