What is the Best Insulation for the Exterior Walls?
Insulating a home is like putting armor on it, protecting it from the elements. But with the growing call for energy-efficient living, homeowners are faced with the complex decision of determining the insulation of choice for exterior walls. In addition to immediate comfort, this choice can affect long-term energy savings, environmental footprint, and overall home valuation. While the options are varied, fiberglass and foam board insulation remain the most popular. But are they really the best?
Interpreting Insulation: More Than R-Values

While R-values (the insulation’s ability to resist heat flow) are critical, they are only the tip of the iceberg. Effective insulation also means humidity control, ease of installation, environmental impact and long-term durability.
Fiberglass Insulation:
Fiberglass has long been a staple in homes, largely because of its balance of affordability and effectiveness.
Advantages: non-combustible, non-absorbent, mildew-proof. Fiberglass can also be obtained from recycled materials, making it a relatively environmentally friendly option.
Cons: It can sag over time, reducing its insulating ability. Installation requires protective clothing, drafts and cold spots may occur if not installed properly.
Foam Board Insulation:
Foam board insulation has a high R-value and is good at preventing thermal bridging, making it an excellent choice for exterior walls.
Pros: Excellent moisture resistance, ideal for wet climates. It is stiff and prevents sagging or settling. Certain types can also act as vapor barriers.
Cons: Some types may be flammable and may release toxic fumes when burned. Over time, it degrades if exposed to sunlight.
Beyond the Mainstream:
Spray Foam Insulation: This insulation is applied in liquid form and expands on contact, filling gaps. Although expensive, it provides an excellent R-value and forms its own moisture barrier.
Cellulose Insulation: Made from recycled paper with fire protection treatment. Its dense composition gives it excellent noise reduction, but over time it settles.
Mineral Wool: This is a fire-resistant insulation that also offers good sound insulation.
Environmental and Financial Impact
Both fiberglass and foam board insulation have their environmental footprints. Producing foam boards with ecologically conscious practices can reduce greenhouse gas emissions. However, both materials offer long-term energy savings that can offset their initial environmental costs.
Choosing the best insulation is not a one-size-fits-all answer. Homeowners need to consider their unique situation: local climate, home design, budget, and long-term goals. It’s also important to work with an experienced installer who can recommend the best product for specific needs.
Stay with Us: Pioneering Superior Insulation Performance
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Ready to embark on the journey to a warmer, more energy-efficient home? Work with our team for a total insulation consultation based on your unique requirements.