The Department of Energy recommends that attics in Chicagoland receive R-49 to R-60 insulation. If you’re retrofitting your home, the exact amount you need depends on how much existing insulation there already is and what material you’re using. Other areas of your home can also benefit from improved insulation, but their R-value requirement is typically lower.
Chicagoland is in the 5A climate zone. This “cool humid” climate requires more insulation than many other parts of the country to ensure adequate comfort, humidity control, and overall building performance.
Thinking of upgrading your home’s current insulation? Here’s everything you need to know about recommended R-values and why hiring ARC Insulation will ensure your retrofit is done correctly.
What is R-Value?
R-value is a measurement of thermal resistance. It expresses how well insulation can slow heat transfer per inch of material. The higher the number after the R, the better insulation it provides.
Every type of insulation has a base R-value rating. For example, closed cell spray foam is R-7, whereas loose fill cellulose is around R-3.7. Insulation contractors achieve recommended insulation levels by layering insulation. For example, if we needed to achieve R-49 in your attic with blown in cellulose, we would add around 13.5 inches of insulation (13.5 x 3.7 = 49.95). However, if we used closed cell spray foam, we would only need to install 7 inches of insulation ( 7 x 7 = 49).
What R-Value Do I Need in Chicagoland? Attics vs Walls, Crawlspaces, Basements, and Floors
Upgraded insulation is beneficial for the entire home. However, each area has different R-value requirements. Since heat naturally rises, the attic generally needs the most insulation. ENERGY STAR notes that adding attic insulation generally offers the most energy savings, and it’s the most accessible.
Here’s a breakdown of recommended basement, wall, and attic insulation R-values for Chicagoland homes:
|
Area of the Home |
Recommended Insulation Amounts |
|
Attic |
Uninsulated Attic:
3–4 Inches of Existing Insulation:
|
|
Exterior Walls |
R-30; lower R-values can be acceptable with adequate exterior insulated sheating |
|
Basement/Crawlspace |
R-15 insulative wall sheathing, or R-19 batt insulation |
|
Floor |
R-30 |
Source: ENERGY STAR and 2021 ICC Standards
How to Check Current Insulation Depth
If you’re upgrading your Chicagoland or Naperville home’s insulation to meet recommended levels, you won’t need to add as much if you already have some existing insulation. But how do you determine how much you have so that you’re not adding excess? The key is an energy assessment.
At ARC Insulation, our energy assessments help you understand how your home performs, where it’s deficient, and where it can be improved. We:
- Identify areas of poor insulation using technology like infrared cameras.
- Measure insulation depth and check the quality of your existing materials.
- Check your home’s overall airtightness to determine if air sealing is necessary before insulation.
- Provide a comprehensive report that explains where you need more insulation and how much is needed to improve your home’s performance.
Why Chicagoland’s Climate Zone 5 Is Different
Recommended R-values depend entirely on climate zone, ranked from 1 to 8 by the International Energy Conservation Code. Zone 1 (like Southeast Florida) needs the least insulation, whereas Zone 8 (like northern Alaska) requires the most.
R-values in Illinois are higher than in other parts of the country because the climate zone is 5A, classified as “cool humid.” Long, cold winters mean you need more insulation (especially in the attic) to prevent heat loss. The ‘A’ denotes humidity, so additional insulation and air sealing considerations are needed to prevent high humidity and subsequent mold growth.
How ARC Insulation Ensures Your Home Gets the Right R-Value
R-value recommendations and code standards should only be viewed as foundational minimums. Most insulation contractors go strictly by the book and never install more insulation, even when a home’s construction and performance require it. They also don’t test their work to see if their upgrade made a measurable difference.
At ARC Insulation, we take a very different approach. We physically measure attic insulation depth with a ruler, and we’re performance-based, so we always test our work to verify that your new insulation improves comfort and energy savings. As a result, you always get the exact amount of insulation you need, no guessing or assumptions.
