At Perrault Construction, we’ve spent over 50 years helping homeowners across Duluth, MN, Superior, WI, and surrounding communities create warmer, more efficient, and more comfortable homes. One of the most impactful upgrades you can make, especially in our extreme Northern climate, is properly insulating your attic.
Fiberglass insulation remains one of the most effective, affordable, and durable solutions for improving energy efficiency and year-round comfort. This expert homeowner’s guide will walk you through everything you need to know about fiberglass attic insulation: what it is, how it works, its benefits, how it compares to other materials, and how to choose the right product for your home.
Whether you choose to do the work yourself or partner with a professional team like Perrault Construction, this guide will help you make informed decisions for a better, more efficient home.
Why Proper Attic Insulation Matters
Here in Duluth and the greater Northern Minnesota region, our winters are long and severe, meaning heat loss can happen fast if your attic isn’t properly insulated. Think of your attic as a cap on your home. Without high-quality insulation, the warm air you pay to heat will rise and escape straight through the roof.
In winter, this forces your furnace to run harder. In summer, the sun heats the roof, turning an uninsulated attic into a hotbox that radiates heat back into your living spaces. Proper attic insulation slows this heat transfer dramatically, stabilizing indoor temperatures and reducing energy costs. At Perrault Construction, we regularly see homeowners save significantly on utility bills after upgrading their attic insulation.
Common Signs Your Attic Needs Better Insulation
If your home is experiencing comfort issues, your attic may be the cause. Watch for:
High Energy Bills: Especially during extreme cold snaps or heat waves.
Uneven Temperatures: Some rooms are more uncomfortable than others.
Drafts: Especially upstairs or near ceilings.
Ice Dams in Winter: A major problem in Duluth, caused by heat escaping through your roof.
Old or Damaged Insulation: Dampness, pest activity, or insulation lower than joist height.
Perrault Construction frequently addresses these issues, especially ice dams and uneven heat distribution, which are common in our region.
Understanding Fiberglass Attic Insulation
Fiberglass insulation has been a trusted material for decades due to its effectiveness and affordability, both important for Minnesota homeowners who experience large temperature swings.
What Is Fiberglass Insulation?
It’s made from extremely fine glass fibers, forming a fluffy, cotton-like material. Available as:
Batts (or rolls) – pre-cut sheets
Blown-in (loose fill) – loose fibers installed with a blower
Both are commonly used by Perrault Construction depending on the attic layout and customer needs.
How Fiberglass Insulation Works
The tangled glass fibers create millions of tiny air pockets. These pockets slow heat transfer, keeping warm air inside during winter and blocking heat intrusion during summer.
This makes fiberglass a reliable thermal barrier suited perfectly for the Northern Midwest climate.
Key Benefits of Fiberglass for Attic Insulation
Energy Efficiency & Heat Control
Fiberglass insulation significantly reduces heat loss and heat gain. At Perrault Construction, we often see homeowners achieve more uniform room temperatures once new insulation is installed.
Noise Reduction
Fiberglass absorbs sound, helping reduce outdoor noise as well as noise transfer between floors.
Affordability
Compared to spray foam, fiberglass is more budget-friendly, making it an excellent choice for cost-conscious homeowners without sacrificing performance.
Durability & Safety
Fiberglass does not settle, deteriorate, or lose effectiveness over time. It’s moisture-resistant, mold-resistant, and non-combustible—ideal for long-term home protection.
Types of Attic Insulation
Perrault Construction installs several insulation types, but fiberglass remains a top option due to reliability and cost efficiency.
Fiberglass Batt Insulation
Great for standard attics with few obstructions. Easy to install for DIYers.
Fiberglass Blown-In Insulation
Perfect for irregular spaces or adding insulation on top of existing layers. Perrault frequently uses blown-in Owens Corning fiberglass to achieve high R-values quickly.
How Fiberglass Compares to Other Materials
Fiberglass vs. Cellulose
Cellulose has a slightly higher R-value per inch
BUT absorbs moisture more easily, which is a risk in Minnesota’s freeze-thaw cycles
Cellulose can settle over time
Fiberglass is naturally non-combustible
Fiberglass vs. Spray Foam
Spray foam seals air leaks extremely well
But costs significantly more
Requires professional installation
For most homes, fiberglass with proper air sealing offers exceptional value
Perrault Construction helps homeowners choose the right option based on budget, attic condition, and energy goals.
Choosing the Right Fiberglass Insulation
R-Value Requirements
In Minnesota (Climate Zone 7), Perrault Construction typically recommends:
R-49 to R-60 for attics
Fiberglass easily reaches these levels using multiple layers or blown-in material.
Moisture & Vapor Barrier Considerations
In cold climates like Duluth, a vapor barrier should face the heated interior of the home to prevent condensation. Perrault’s installers ensure vapor barriers are positioned correctly based on local codes.
Preparing Your Attic for Installation
Before installing insulation, Perrault Construction always performs:
Air Sealing
Gaps around pipes, vents, and wiring must be sealed before insulation is added. Insulation does not stop air movement.
Ventilation Check
We ensure soffit, ridge, and gable vents are open and unobstructed for proper airflow and moisture control.
Safety Gear
Fiberglass can irritate skin and lungs, so protective clothing and respirators are essential.
DIY Tools & Materials Needed
Tape measure
Utility knife
Protective gear
Caulk or expanding foam
Blower machine (for loose-fill)
Homeowners doing DIY blown-in insulation often rent a blower, though Perrault’s team provides professional installation for more accurate coverage.
How to Install Fiberglass Insulation
Installing Fiberglass Batts
Start at the edges and work inward
Lay batts gently without compression
Cut around obstructions
Add a second perpendicular layer if needed
Ease of Installation
Batts are DIY-friendly; blown-in fiberglass is also possible to DIY, but easier with professional equipment and technique.
Final Thoughts
Upgrading your insulation is one of the smartest home improvements you can make, especially in a region like Northern Minnesota, where severe cold is common. Fiberglass insulation delivers excellent performance, affordability, and long-term reliability.
When to Hire a Professional (Perrault Construction Recommendation)
Consider professional installation if:
Your attic has limited access
Old insulation needs removal (moisture, mold, pests)
You want maximum R-value coverage
You want warranty-backed workmanship
You prefer a fast, guaranteed installation
Perrault Construction offers 10-Year Labor Warranties, uses top brands like Owens Corning, and understands Duluth’s unique climate better than anyone.
Tips for Long-Term Energy Savings
Keep vents clear
Check for moisture or pests periodically
Seal new air leaks as they appear
Maintain proper attic ventilation
A well-maintained attic protects your home year-round.
Ready to Improve Your Home’s Comfort and Efficiency?
Contact Perrault Construction for a free attic insulation assessment.
With over 50 years of experience, we provide expert installation, high-quality materials, and workmanship you can trust.