Sealing These 10 Home Air Leaks Can Save You Lots of Money

woman applying weatherstripping to a window.

If you live in an older house that has not been fully weatherized, somewhere between 20% and 50% of your heating and cooling bills can be attributed to air leakage alone!

In fact, energy inefficient homes are such a problem, that properly insulating and sealing your home is one of the very best things you can do to protect the planet. 

Weatherizing and Sealing

Weatherizing and sealing air leaks around your house is the first step you should take to improve the energy efficiency of your home. The energy, time, and money you spend will pay for itself quickly—often in one season!

Air infiltrates into and out of your home through every hole and crack. About one-third of this air infiltrates through openings in your ceilings, walls, and floors.

One of the quickest ways you can save on your heating and cooling bill is to caulk, seal, and weatherstrip all seams, cracks, and openings to the outside. This is best done in the late summer and early fall, before the weather gets too cold, but you can weatherize in the spring too, before it heats up enough to need the air conditioner.

Many weatherstripping and caulking materials will not adhere well if the weather is lower than 60 degrees F.

More Ways to Improve Your Home Energy Efficiency

Testing for Home Air Leaks

First, test your home for air-tightness. On a breezy day, carefully hold a lit incense stick, smoke pen or a thermal leak detector next to your windows, doors, electrical boxes, plumbing fixtures, electrical outlets and switches, ceiling fixtures, baseboards, attic hatches, and other locations where there is a possible air path to the outside.

If the smoke stream drifts horizontally, you have located an air leak that may need caulking, sealing, or weatherstripping.

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10 Common Home Air Leaks

When weatherizing your home, these are the most common areas that need to be sealed up:

1. Doors and Windows

Caulk and weatherstrip doors and windows that leak air.

2. Utility Openings

Caulk and seal air leaks where plumbing, ducting, or electrical wiring penetrates through walls, floors, ceilings, and soffits over cabinets.

3. Switch Plates and Outlets

The holes that carry our electrical outlets can be surprising sources of drafts and lost heating and air conditioning. Install foam gaskets behind outlet and switch plates on walls.

4. Behind Insulation

Look for dirty spots in your insulation, which often indicate holes where air leaks into and out of your house. You can seal the holes with low-expansion spray foam made for this purpose.

5. Wall Joints and Floor Joists

Look for dirty spots on your ceiling paint and carpet, which may indicate air leaks at interior wall/ceiling joints and wall/floor joists. These joints can be caulked.

6. Window Panes

Install storm windows over single-pane windows or replace them with more efficient windows, such as double-pane, or argon-filled. At a minimum, cover drafty windows with insulating window plastic during the winter.

7. Gaps Around Baseboards and Window Frames

Use a foam sealant around larger gaps around windows, baseboards, and other places where warm air may be leaking out.

8. Exhaust Fans

Kitchen, bathroom and attic exhaust fan covers can keep air from leaking in when the exhaust fan is not in use. The covers typically attach via magnets for ease of replacement.

9. Door Thresholds

Installing draft stoppers and threshold weatherstripping is a great way to stop air from leaking out from underneath your doors. Do the same to your garage door too!

10. Chimneys and Flues

When the fireplace is not in use, keep the flue damper tightly closed. A chimney is designed specifically for smoke to escape, so until you close it, air escapes—24 hours a day! Fireplace flues are made from metal, and over time repeated heating and cooling can cause the metal to warp or break, creating a channel for hot or cold air loss. Inflatable chimney balloons and flue plugs are designed to fit beneath your fireplace flue during periods of non-use. They are made from several layers of durable plastic or wool, and can be removed easily and reused hundreds of times. Should you forget to remove the balloon before making a fire, the balloon will automatically deflate within seconds of coming into contact with heat.

A thorough job of leak sealing can cut your home’s total air leakage and thereby reduce your heating and cooling bills up to 20-30%. This season alone, that could mean up to $300 or more in savings!

This video will help you get started!

YouTube video
This article was excerpted from my book Sustainability Starts at Home – How to Save Money While Saving the Planet, where you can find even more money-saving, planet-friendly tips.

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