Building Envelope
Introduction to Building Envelope
The building envelope refers to the barrier between the interior and exterior of a building, including walls, roofs, windows, doors, and foundations. The building envelope controls the movement of heat, air, moisture, and noise throughout the building, impacting energy use, health, and comfort.
How Building Envelope Systems Work
Improvements to your building envelope reduce energy consumption and help to maintain the comfort of the building. Energy efficient building envelope improvements include:
- Installing lashing, sealant, and/or caulk around windows, doors, and other openings to decrease airflow between outdoor and indoors, and between conditioned and unconditioned building areas.
- Installing insulation in exterior walls and attics to slow down transfer of heat between outdoors and indoors. Insulation can improve comfort, and make it more cost effective to keep the interior cooler in the summer and warmer in the winter
Building owners may opt to receive an energy audit from a qualified professional to determine what building envelope improvements they might need. Local energy codes will dictate minimum requirements of building envelope improvements.
Average Lifespan: 10-50 years
Typical Payback Period: 1-20 years
Eligible measures and technical standards
| Attic insulation | Ceiling starting R-Value must be ≤R19, upgrade to ≥R38 |
| Floor insulation | Floor between conditioned and unconditioned space (e.g., basement, garage); starting R-value must be ≤R6, upgrade to ≥R19 |
| Wall insulation | Wall starting R-value must be ≤R4, upgrade to ≥R13; no below-grade walls or interior walls |
| Windows replacement | ENERGY STAR (when possible), U-factor ≤0.27; not for unconditioned spaces |
