Insulation is the most cost-effective energy improvement most homes can make. Understanding R-values and where to install insulation helps prioritize the most impactful upgrades.
R-Value Explained
R-value measures thermal resistance — higher numbers mean better insulation. The total R-value of a wall or ceiling depends not just on the insulation but on all the layers from interior to exterior. Air sealing and moisture management are as important as R-value.
Where to Insulate First
In most climates, attics provide the highest return on investment for insulation upgrades. Heat rises, and an under-insulated attic lets the most heat escape in winter and the most heat enter in summer. Insulate to R-49 or higher in attics in most climate zones.