What to choose? Cellulose vs Fiberglass?

Cellulose vs Fiberglass What to choose?

Blown-In Fiberglass

Pros

  • Does not settle – maintains R-value over time when properly installed

  • Cleaner install – less dust, less mess in the attic and home

  • Lightweight – puts less load on ceiling drywall

  • Moisture resistant – won’t absorb water or promote mold growth

  • Long lifespan – performance stays consistent for decades

  • Easy to top off later – great for future energy upgrades

Cons

  • Lower R-value per inch than cellulose

  • Air sealing requires prep – needs proper air sealing underneath to perform at its best

  • Slightly higher material cost in some markets

Best Use Case

  • Homes with existing fiberglass

  • Homeowners who want a clean, long-term solution

  • Attics where moisture control is a concern

Blown-In Cellulose

Pros

  • Higher R-value per inch

  • Dense-packed performance – can help reduce air movement when installed correctly

  • Uses recycled material (paper) – eco-friendly appeal

  • Naturally pest-resistant due to borate treatment

Cons

  • Settles over time (typically 10–20%), reducing effective R-value

  • Heavier material – adds more load to ceiling drywall

  • Absorbs moisture – can hold water and contribute to mold issues

  • Messier install – more dust and cleanup

Best Use Case

  • Attics that already have cellulose

  • Situations where maximum R-value per inch is needed (limited space)

  • When dense-pack air control is specifically desired

Location: Meridian, Idaho

Issue: Best insulation for my attic?

Cause: Too much information.

Our Resolution:  Simple Pro’s and Con’s list

Call us for a free in-home quote for your attic insulation.