The first winter in my apartment, I could not figure out why my heating bill was so high. I kept the thermostat at 68. I wore sweaters. But standing near the living room window felt like standing in front of an open refrigerator. The cold air was not sneaking in — it was marching through.

I found the drafts by holding a lit candle near the window frame. The flame flickered sideways. That was a hundred dollars a month of heated air escaping through gaps I could not even see.

Find the Leaks First

On a windy day, walk around your house with a lit incense stick or a candle. Hold it near every window edge and door frame. If the smoke or flame wavers, you have found a leak. Mark the spot with a small piece of painter’s tape so you remember where to fix.

Weatherstripping — The Five Dollar Fix

For gaps around the window sash — the part that moves — adhesive foam weatherstripping tape is your best friend. It costs about five dollars a roll at any hardware store. Cut it to length, peel the backing, and press it into the gap where the sash meets the frame. When you close the window, the foam compresses and seals the gap.

This alone cut the draft in my living room by about eighty percent. The candle barely flickered after I applied it.

Window Film for Bigger Problems

If your windows are old single-pane glass, weatherstripping will not be enough. Buy a window insulation film kit — the kind you apply with double-sided tape around the frame and shrink tight with a hair dryer. It creates an air pocket between the film and the glass that acts like a second pane. The film is nearly invisible once installed and makes a huge difference in rooms that never seem to warm up.

The Pool Noodle Hack

For sliding windows and doors that have a gap along the bottom track, a foam pool noodle cut to length and wedged into the track works surprisingly well. It is ugly but effective for windows you do not open during winter. Cover it with fabric if the look bothers you.