The DIY 'Vacuum' Leak Test
Impact
Medium
Difficulty
Easy
Speed
Instant
You don't need a $1,300 blower door test to find major air leaks. You just need a windy day and a stick of incense (or a single candle).
Shut all windows and doors, and turn on every exhaust fan in your house—the kitchen hood, the bathroom fans, even the dryer. This creates a slight 'negative pressure' inside, effectively trying to suck air in through any cracks. Now, walk around with your lit incense stick near window frames, outlets, and the attic hatch. Where you see the smoke dance or blow sideways, you've found a 'thermal leak'.
Most people find that their electrical outlets on exterior walls are major culprits. A simple $5 pack of foam 'outlet gaskets' can shut these down in minutes. It's a low-tech way to see the invisible 'wind' that's making your HVAC work twice as hard. Seal the smoke, stop the draft, and keep your heat where it belongs! It's the cheapest energy audit you'll ever perform.
Quick Check Before You Try This
Use this tip as a practical starting point, then check whether it fits your home. The right answer can change with climate, utility rates, equipment age, household routines, and whether you rent or own.
| Check | Why it matters |
|---|---|
| Your actual bill | A high-impact tip in one home may be minor in another. |
| Equipment age | Older appliances and HVAC systems often waste more energy. |
| Comfort tradeoff | A good energy habit should not make the home harder to live in. |
| Safety or warranty limits | Electrical, HVAC, plumbing, and appliance work should stay inside manufacturer and code rules. |
For a broader next step, browse the EnergyBS guide library and compare this envelope tip with a full article before making a paid upgrade.