How to find drafts in your house: 4 quick tests

If some rooms stay cold even with the heat on, air is probably leaking in. You can find most leaks in under an hour with things you already own.

Pick the right moment

Test on a cold or windy day with the heating on. The bigger the difference between inside and outside, the easier drafts are to feel. Evenings are best, because light leaks are easier to see in the dark.

The 4 tests

1. Tissue test. Hold a single tissue next to the edge of a door or window and move it slowly. If it flutters or leans, air is moving.
2. Smoke test. Light an incense stick, blow out the flame, and move it slowly along edges. Smoke that bends sideways points to a leak. Never leave it unattended.
3. Hand test. Wet the back of your hand and run it along gaps. Damp skin feels moving air much better than dry skin.
4. Light and paper test. At night, have someone shine a flashlight around a closed door while you watch from the other side. Then close the door on a sheet of paper. If it slides out with no grip, the seal is loose.

Where to look first

• Outside doors: the gap underneath and the sides of the frame.
• Windows: where the two panels meet, and the trim around the frame.
• Outlets and light switches on outside walls: the leak most people never suspect.
• The attic hatch: warm air rises straight out through any gap.

Free fixes you can do tonight

• Roll a towel and press it against the bottom of a drafty door.
• Lock every window. Locking pulls the panels together and closes small gaps.
• Close the fireplace damper whenever the fireplace is cold.
• Close curtains at night, especially on windows that feel cold to the touch.