When budgeting for a construction project, insulation is often one of the first places builders and developers look to cut costs. Fiberglass batt insulation is cheap, widely available, and familiar to most contractors — so it gets specified by default. But the upfront cost of insulation is only a fraction of its true lifetime cost. And when you factor in energy bills, maintenance, replacement, and moisture damage, cheap insulation is almost always the most expensive choice you can make.
ThermBoard® rigid insulation boards cost more upfront than fiberglass — but deliver dramatically lower lifetime costs through superior energy performance, zero maintenance, and 50+ years of consistent R-value with no replacement required.
The Hidden Costs of Fiberglass Insulation
Fiberglass batt insulation has a low purchase price — but that low price comes with a long list of hidden costs that accumulate over the lifetime of the building.
Degrading R-Value: Fiberglass insulation sags and settles over time, creating gaps in the insulation layer that allow heat to bypass the insulation entirely. A wall insulated to R-19 at installation may be performing at R-12 or less within 10-15 years — costing significantly more in heating and cooling energy every single year.
Thermal Bridging: Fiberglass batt insulation only fills the cavity between studs — it does not cover the studs themselves. Every wooden stud in a framed wall is a thermal bridge — a path for heat to bypass the insulation. This reduces whole-wall R-value by up to 30% compared to the rated R-value of the insulation, adding thousands of dollars in unnecessary energy costs over the lifetime of the building.
Moisture Damage: When fiberglass gets wet — from condensation, leaks, or high humidity — it loses R-value and becomes a breeding ground for mold. Mold remediation in a wall cavity can cost $10,000 to $50,000 or more, depending on the extent of the damage. And the insulation must be completely replaced after remediation — adding the full cost of new insulation on top of the remediation cost.
Replacement Costs: Fiberglass insulation has a practical lifespan of 10-15 years before sagging, settling, and moisture damage reduce its performance to unacceptable levels. Over the 50-year lifetime of a typical building, fiberglass insulation may need to be replaced 3-4 times — each replacement requiring significant labor and disruption to the building.
The True Cost of Spray Foam
Spray foam insulation has a higher upfront cost than fiberglass — but it also comes with significant hidden costs. Spray foam requires specialized equipment and trained installers, adding to labor costs. It requires a thermal barrier — typically drywall — to meet fire safety codes, adding material and labor costs. And spray foam can shrink and crack over time, creating gaps that must be identified and repaired to maintain performance.
Spray foam also has a significant environmental cost — the blowing agents used in spray foam have a high global warming potential, and spray foam cannot be recycled at end of life, going directly to landfill.
ThermBoard® — The Lower Lifetime Cost Choice
ThermBoard® rigid insulation boards cost more upfront than fiberglass — but the lifetime cost comparison tells a very different story.
No Degradation: ThermBoard® maintains its full rated R-value for 50+ years with zero maintenance. No sagging, no settling, no gaps — just consistent thermal performance for the full lifetime of the building.
No Thermal Bridging: Continuous ThermBoard® insulation covers the entire wall surface — including the studs — eliminating thermal bridges and delivering true whole-wall R-value performance. This translates directly to lower energy bills every month for the full lifetime of the building.
No Moisture Damage: ThermBoard® is highly resistant to moisture — no mold risk, no performance loss, no remediation costs. Ever.
No Replacement: ThermBoard® is installed once and performs for the full lifetime of the building. No replacement, no disruption, no additional cost.
Lower Energy Bills: ThermBoard® delivers up to 35% reduction in heating and cooling energy costs compared to conventional insulation. Over the 50-year lifetime of a typical building, this energy saving can amount to tens of thousands of dollars — far exceeding the higher upfront cost of ThermBoard®.
The Numbers Tell the Story
Consider a typical residential home insulated with fiberglass batt insulation versus ThermBoard® rigid insulation. The fiberglass option may cost $3,000-$5,000 less at installation — but over 50 years, the higher energy bills, replacement costs, and potential moisture remediation costs of fiberglass insulation will far exceed that initial saving. ThermBoard® pays for itself many times over through lower energy bills alone — before accounting for the elimination of replacement and remediation costs.
Make the Smart Long-Term Choice
Do not let a lower upfront price lead you to the most expensive insulation decision you will ever make. Choose ThermBoard® rigid insulation — the lower lifetime cost choice for any residential or commercial building project. Contact our team for a free specification consultation and lifetime cost comparison for your specific project.