Draftiness

Draftiness refers to the condition in which indoor spaces experience undesired air movement caused by leaks and gaps in a building envelope or other systems. This movement allows cool outside air to enter and warm indoor air to escape, leading to uncomfortable drafts and higher energy use.

Common sources include gaps around doors and windows, cracks in walls or foundations, gaps at attic hatches or chimney openings, penetrations for electrical outlets or plumbing, and leaky ducts or vents. Poor insulation and inadequate sealing amplify draftiness, especially in older or poorly weatherized structures. Draftiness can also arise around fireplaces when dampers are left open or not properly sealed.

Effects of draftiness extend beyond mere comfort. It can create cold spots, especially near floors and windows, and increase heating costs by raising the amount of energy needed to maintain a steady indoor temperature. Excessive drafts may contribute to condensation and moisture problems, which can lead to mold growth or material wear over time.

Assessment of draftiness is often done through air-leak measurements such as blower door tests, which report air changes per hour (ACH) or ACH50. More informal methods include visual inspection, feel tests around openings, or smoke pencils to identify air paths.

Mitigation focuses on sealing and insulation. Common measures include weatherstripping doors and windows, caulking gaps, installing door sweeps, sealing electrical outlets, insulating attics and walls, and repairing or upgrading ducts and fireplaces. Together, these steps reduce draftiness, improve comfort, and lower energy consumption.