DIY: Window Caulking

Nobody likes sky-high heating bills—global warming, even less so. Yet according to the Alliance to Save Energy, the average U.S. household will pay $2,300 this year on residential energy costs, with heating accounting for almost 45 percent of that total. You can help knock out soaring heating bills and fight climate change this winter season by caulking your windows. Though the gaps and cracks around the window frame seem tiny, they help contribute to the approximately 10 percent of heat lost through windows, according to the Department of Energy.

Plus, caulk is handy for other drafty crevices around the house, like in the bathroom and kitchen. And certain types of caulk prevent icky mold, which can muck up your indoor air quality and can cause stuffiness, eye irritation, wheezing, or skin irritation among sensitive populations, according to the Centers for Disease Control.

Below are six easy steps to plugging up drafts and lowering your heating bill.

Caulking gun (ask to borrow your neighbor’s!)
Putty knife
Old rag
Lead test kit (if your paint is really old)

1. Find the draft. To do this, simply wait for a windy day, light a candle or some incense, and slowly move it around suspected air leaks, like doors and windows. Wherever the smoke or flame wavers, you can bet you’ve got a leak close by, says Ronnie Kweller from the Alliance to Save Energy.

2. Scrape and clean the area to be caulked to remove any paint chips, dirt, old caulk, or anything else in the way of a clean, dry surface. This can be done using a putty knife, which can be found at your local hardware store for about $5, and an old rag. Note: If the paint on your walls is fairly old, you may want to first test it for lead before scraping because lead-based paint is best left alone.

3. Get your tube of caulk and cut the top off at a 45 degree angle. We recommend Green Series Acrylic Urethane Indoor/Outdoor Sealant, which is Greenguard certified for healthy indoor air quality, and AFM Safecoat Caulk, a non-toxic, water-based caulk that won’t crack or dry out. Or, if you don’t have a caulking gun, try Titebond’s Tub and Tile Caulk, which only requires hand power and can be used on multiple surfaces while meeting stringent VOC and indoor air quality regulations.

4. Run a thin bead of caulk (about half an inch) between the window frame and siding to ensure a leak-proof window. Also, be sure to push caulk into any other sources of leaks like cracks and gaps that your incense/candle burning revealed. If you’re standing in front of a window and you can still feels wisps of air coming through, recheck it for possible culprits.

5. Smooth the caulk with something flat, like a Popsicle stick or even the pad of your wetted finger.

6. Go have fun while you wait for your caulk to dry, which can take anywhere from 4 to 24 hours (check the label for details).

**Still unsure of your caulking skills? Check out the Alliance to Save Energy Web site to get step-by-step video instructions on energy-saving tips like caulking windows and doors and getting a home energy audit.


Lead testing

• Lead testing strips from PRO-LAB
• Lead testing swabs from Hybrivet Systems Inc.
EPA approved water testing facilities by state if you want 
professionals to test your water for lead and other contaminants.

Eco-friendly caulk
Green Series Acrylic Urethane Indoor/Outdoor Sealant. It’s extremely low VOC and Greenguard certified for healthy indoor air quality.
Titebond’s Tub and Tile Caulk (no caulking gun required). Meets stringent VOC and indoor air quality regulations.
AFM Safecoat Caulk. A non-toxic, water-based caulk that won’t crack or dry out.

Plenty is an environmental media company dedicated to exploring and giving voice to the green revolution that will define the 21st Century. Click here to subscribe to Plenty.


William C
William C2 months ago


W. C
W. C2 months ago

Thank you.

Debra C.
Debra C8 years ago

Thanks for the suggestion.

Tessa Fitzgerald
Tessa Fitzgerald9 years ago

I'm amazed no one said this! There is an even more green way to block drafts! Melt some beeswax and dip cotton string in it then lay it over the draft. Keep applying string with wax until draft is blocked.

Hope this helps!


Jody Palmer
Past Member 9 years ago

Thanks for the directions, it's hard to be all alone in the house. I can now do it on my own.

Debbie Dahl
Debbie Dahl9 years ago

Now that I know how to do it, and what I need, I'm going to Home Depot right now! Thanks.

Rhiannon Myst
Rhiannon Myst9 years ago

great ideas and we really need them this year...its cold and heating oil is so expensive...its a shame.

Carolyn T.
Carolyn T9 years ago

Thanks for the information...especially the products you recommended. And, Dwight, thank you for the great tip!

Joyce Malone
Joyce Malone9 years ago

These are great ideas whick my family have already used several and they work! We all need to save money and protect our families and the environment!Thanks!

JoAnna B.
JoAnna B9 years ago

Thanks I will let my lanlord read this..Hopefully he will replace some of the really old windows..he has already replaced 4 with great new ones..he has 3 more to go!