Locate air leaks

Written by terrapass


Look around your house for gaps or cracks that could be leaking air, including the attic floor, edges of doors and windows, electrical outlets and switches, and pipe entrances.

Light an incense stick and hold it close to window edges and other possible leaks. If the smoke coming from the stick goes horizontal, you’ve found a crack.

To test doors and windows, close them on a used piece of paper laying against the frame. If you can remove the paper without tearing it, then your seal could be tighter.

**How this helps**

A little air flow in a house is a good thing, but too much and you could be losing your nice (expensive) warm air to the freezing outdoors. Checking around the house will help you to understand where your leaks are and whether you should consider sealing them.

**More information**

– About air flow from the DIY Network.
– US Department of Energy guide to finding and sealing air leaks.

**Related tips**

– Upgrade your weather stripping on doors and windows
– Install a programmable thermostat

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  1. Monty

    We just had an energy advisor visit our house and professionally locate the leaks. It was quite eye opening. Despite doing everything ‘green’ we could, our home had issues we had not even considered. I highly recommend it to anyone who has that option. Check with your local power company to see if they offer something like this.

  2. enaudit

    Just be sure you’re not making the house too tight. If you depend upon natural air flow (gaps and wind) to provide your air exchanges, you may be inadvertently making it too tight. ONE sign of that is condensation on windows that didn’t occur prior to tightening. A potential safety issue is that natural draft combustion appliances don’t remove the exhaust gases (DO install CO detector(s) anytime you have one of them). The recommended rate of air exchange is 1 air change every 3 hours, that’s ALL of the air in the house being exchanged in 3 hours. The only sure way to know is to have an infiltration measurement test (blower door) by someone like an energy auditor. FYI, if you want to be as efficient as possible, install a mechanical air exchange device (different types are available) to provide exactly the correct air exchange rate, then you can make the house really tight. One more thing, PLEASE DO NOT USE UNVENTED COMBUSTION HEATERS!!

  3. richard schumacher

    Why th’ heck is there no bathroom exhaust fan with a built-in positive closure? Instead they have air pressure-operated flaps, which stop backdrafts but do almost nothing against warm air rising out.

  4. Dori P.

    Richard, I have had the very same question! You should design one and cash in. 🙂

  5. Chris Prelitz

    Spider webs by interior doors and windows are also a cue that you have air moving. Spiders will typically build webs where there is air movement. And, for some nice clear peel-and- stick weatherstrip, visit:

  6. Dean

    Use a two-part epoxy to glue a steel washer to your backdraft flap, and then mount a magnet as a catch to its frame. The frames for mine are steel, so I didn’t have to glue the magnet in place. When the flap falls closed, the magnet holds it there. It’s not a perfect seal, but it’s better than hanging partially open. Most vent fans should have plenty of generate plenty of pressure difference to open the flap up.