Why Drafts Cost More Than You Feel
A draft isn't just a comfort problem — it's money leaving the house. Every cubic foot of warm air that escapes through a gap is replaced by cold air that your heater has to warm back up. On Long Island, where heating runs October through April, even small leaks add up to hundreds of dollars a season. The good news: you don't need special equipment to find them. The incense stick test is a 100-year-old trick that still works.
The Incense Stick Test
On a cold, windy day (when leaks are most active):
- Turn off any fans, the furnace, and the dryer so the air in the house is still.
- Light an incense stick and hold it within an inch of the surface you're testing.
- Watch the smoke. If it drifts sideways or gets sucked out of the room, you've found a leak. If it rises straight up, that spot is sealed.
Move methodically — a full home sweep takes 20–30 minutes and finds leaks you'd never locate by feel alone.
Where to Check (and What to Do About Each)
Windows
- Test along the sash (where the two window halves meet), the sides, and the top and bottom of the frame.
- Fix: Replace worn weatherstripping on operable windows. Caulk the gap between the frame and the wall (interior and exterior). For older double-hung windows, install V-strip weatherstripping in the channels.
- For gaps you can't seal permanently, use rope caulk — press it in for winter, peel it out in spring.
Exterior doors
- Test the full perimeter and the threshold at the bottom.
- Fix: Add or replace a door sweep at the bottom. Replace compressed weatherstripping around the frame. Many thresholds are screw-adjustable — a quarter-turn can close a gap for free.
Electrical outlets and switches on exterior walls
- Hold the incense near the outlet plate — a surprising amount of cold air enters through the wall cavity and out the outlet.
- Fix: Turn off the breaker, remove the cover plate, and install a foam gasket behind it (about $0.25 each). Replace the plate. Five minutes per outlet.
Attic hatches and pull-down stairs
- This is one of the biggest leaks in most homes — an uninsulated attic hatch is a hole in your ceiling.
- Fix: Buy or build an insulated attic hatch cover. For pull-down stairs, install a pre-made insulated tent or foam box that seals against the frame.
Recessed (can) lights
- Older, non-IC-rated can lights are not airtight and leak warm air straight into the attic.
- Fix: Replace with IC-rated airtight retrofit inserts (about $15–$30 each) that seal the leak and are safe to insulate over. Don't just foam over a non-IC light — it's a fire hazard.
Plumbing and wiring penetrations
- Check under sinks and in the basement where pipes and wires enter the house. The hole drilled for a pipe is often far larger than the pipe itself.
- Fix: Seal the gap with low-expansion spray foam or caulk. For larger gaps around pipes, use foam backer rod first, then caulk over it.
The dryer and exhaust vents
- Check the wall behind the dryer and any bathroom or kitchen exhaust vents.
- Fix: Make sure the vent has a flapper or damper that closes when the fan is off. Clean it — a lint-clogged flapper stays open and acts as an open window all winter.
The Professional Option: A Blower Door Test
If you've sealed the obvious leaks and rooms still feel drafty, a blower door test (offered by energy auditors and some HVAC companies) pressurizes the house and measures the total leakage. It runs $300–$500 on Long Island and often comes with a prioritized list of the biggest leaks — plus it may qualify you for utility rebates on insulation.
The Payoff
Most homeowners find and seal 20–40 leaks in a single afternoon with $40 of materials. The result is a quieter, cozier home and a heating bill that's noticeably lower the very next month. Start with the incense test — it turns an invisible problem into something you can see and fix.