Pull the gun smoothly along the crack. Don't go back and forth. Aim to fill the void, not just cover the top.

The culprit isn't your furnace or your insulation—it’s the invisible gaps around your windows.

Snip the caulk tube nozzle at a 45-degree angle. You want a bead the size of a pencil lead, not a garden hose. Poke the inner seal with the wire on the gun.

Wet your finger (or a plastic spoon) with soapy water. Run it lightly over the bead to push the caulk into the crack and smooth the surface.

Remove old, cracked caulk using a 5-in-1 tool or a stiff putty knife. Vacuum out dust and dirt. Wipe the area with rubbing alcohol—you need a pristine surface.

You’ve felt it. That mysterious shiver while sitting on the couch. The way the curtains puff inward on a windy day. The sudden spike on your heating bill that makes you double-check the thermostat.

Sealing your windows isn't glamorous. No one will throw you a parade for a perfect bead of silicone. But your home will be warmer, quieter, and drier. And on a cold January morning, when you sit next to that window and feel nothing —no draft, no chill—you’ll know it was worth it.