Disclosure: I work for a building science company in the western suburbs. This is just how to check your own house; no sales pitch.

Most people blame windows for drafts, but in our climate the bigger leaks are usually in the attic floor and the basement. Cold air comes in low, warm air leaves high.

How to check:

Pick a cold, windy day. Turn on bath fans and the kitchen hood to slightly depressurize the house.

Hold a lit incense stick (carefully) near outlets on exterior walls, baseboards, the attic hatch, and around pipes under sinks. Watch where the smoke gets pulled sideways.

In the basement, check the rim joist (where the wood framing sits on the foundation). Cold spots or cobwebs moving are a giveaway.

In the attic, look for dark or dirty patches on fiberglass insulation. That's dust filtered out of air leaking through from below, often over light fixtureso and wall top plates.

Small gaps: caulk. Bigger gaps: canned foam or rigid foam board. Around chimneys and flues, use fire-rated material only.…