In the average home, more than half of the conditioned air inside leaks out every hour, and an equal amount of unconditioned outdoor air gets drawn in to replace it. Finding and sealing air leaks in the envelope is vital to control that air exchange to improve your home’s overall energy efficiency and boost your comfort.
Identifying Where Leaks Occur
Air leakage usually occurs through gaps and cracks in the envelope that added together can have the same effect as leaving a window wide open year round. To find leaks, hold up a smoke pencil or burning stick of incense and watch the smoke column. If the smoke wavers in any of these areas, you’ve located a leak that needs sealing:
- Window and door frames.
- Crown moldings and baseboards.
- Electrical outlet plates and light switches.
- Appliance ventilation and exhaust fans.
- Penetrations for pipes and wiring.
- The fireplace.
- In the attic, check around knee-walls, a chimney or furnace flue, plumbing vent pipes, dropped ceilings, and recessed light fixtures.
- In the basement, check the spaces around the rim joists as well as any windows.
How to Seal Different Leak Sources
The most effective sealing method depends on the type of leak:
- Leaks around fixed window frames and narrow gaps around attic and shell penetrations can be sealed with caulk. Use all-purpose latex caulk indoors, and a more durable silicone or siliconized latex product outdoors.
- For leaks around moveable components like doors and window sashes, use weatherstripping. Vinyl gaskets are best around an older door, while tension-seal or V-shaped weatherstripping are ideal for tight-fitted doors and casement or double-hung windows.
- For larger spaces around the rim joists and penetrations through the exterior envelope, use expandable spray foam.
- Around a chimney/flue and recessed lights, install metal flashing then apply heat-resistant caulk.
If you’re concerned about locating all the air leaks around your home, schedule an energy audit. A trained and experienced auditor uses specialized equipment that’s able to pinpoint even tiny leaks so they can be sealed effectively.
For help sealing air leaks in your Portland home, contact us at Roth Heating & Cooling today.
Our goal is to help educate our customers in the Metro Portland, Oregon area about energy and home comfort issues (specific to HVAC systems).
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