Heat Loss Calculator for Minnesota Insulation Standards
Calculate total building heat loss (BTU/hr) based on Minnesota Energy Code (MN Rule 1322, Section R402) insulation requirements. Enter your building dimensions and construction details to estimate heating load.
MN Climate Zone 6 minimum: R-20 continuous or R-13+5ci
MN Climate Zone 6 minimum: R-49
MN Climate Zone 6 minimum: R-30 (floor over unconditioned space)
MN Climate Zone 6 maximum: U-0.30
MN Climate Zone 6 maximum: U-0.20
MN Energy Code target: ≤3 ACH50 (≈0.15–0.35 natural ACH)
MN 99% design temps: Minneapolis -16°F, Duluth -21°F, Rochester -17°F
Formulas Used
Conductive Heat Loss (opaque assemblies & windows/doors):
Q = (1/R) × A × ΔT | Q = U × A × ΔT
Infiltration Heat Loss:
Qinf = 0.018 × ACH × V × ΔT
Annual Heating Energy Estimate:
Eannual = Qtotal × HDD × 24 / ΔTdesign