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.