Step 1 · Inspect for Drafts

Examine the entire perimeter of the window, both inside and out. Pay close attention to the meeting rails of a double-hung window, the areas where the sash meets the frame, and around any trim or molding. Look for gaps, cracks, peeling paint, or any signs of poor sealing. You can use a smoke pencil or incense stick to help visualize drafts by observing the direction of smoke.