Attic Insulation: How Much Do You Need?

Attic Insulation: How Much Do You Need? Attic insulation is one of the most cost-effective upgrades a DIYer can make to reduce heating and cooling bills and improve comfort. Uninsulated roofs can account for roughly 25–30% of heat loss in a typical house, so getting the right attic R-value and insulation depth matters. This guide walks through climate-based R-value targets, how to measure your attic and calculate quantities, material trade-offs (including blown-in cellulose), ventilation and air-sealing priorities, cost and payback examples, and clear DIY vs professional decision points. TL;DR: - Aim for R-30 to R-60 in cold climates, R-19 to R-38 in mixed climates, and R-13 to R-30 in warm climates; full attics save about 25–30% of heat loss when upgraded. - Measure area and average insulation depth, convert depth to R-value using material R/inch, then buy blown or batt quantities plus 10% waste. - Air-seal before insulating, choose material based on budget and space (blown cellulose ...