Caulking an exterior windowSealing air leaks in your home with caulk is an easy DIY project you can do in two hours or less and could save you 10-20% on your energy bills.

Air leaks around the windows and doors of your home can waste a lot of your energy and that wasted energy costs you money in the form of utility bills that are higher than they could be.

Related: Winter Heating Tips

Luckily for you, many of the most common sources of air leaks are easy to seal yourself using caulk. This is a very affordable fix as well. The average tube of white latex window and door caulk will only cost 2-3 dollars. A standard caulk gun to help you apply it should only cost around $5 to $10.

At those kinds of prices, this project could pay for itself in just a few months.

What you’ll need to seal air leaks

  • Caulk for sealing windows and doors (latex or silicone-based)
  • Caulk gun
  • Putty knife or large screwdriver (for removing any old caulk)
  • Paper towels or a rag for cleanup
  • Flashing material  for larger openings (e.g., thin board sheathing, sheet aluminum, etc.)


How to use a caulk gun

Most caulk comes in disposable cartridges that fit in half-barrel caulking guns. A caulk gun with an automatic release will probably be easier to use.

How much caulk do I need to seal my windows and doors?

You’ll need about a half-cartridge per window or door and four cartridges for the foundation sill of your home.

How to choose the right kind of caulk

Caulking compounds vary in strength, properties, and prices. Water-based caulk can be cleaned with water, while solvent-based compounds require a solvent for cleanup. Use this guide from to help you select the right kind.

How to seal air leaks with caulk

1. First, clean all areas you are going to caulk first. Remove any old caulk and peeling paint with a putty knife or screwdriver. A simple cleaning using dish soap and water mix will give you better adhesion of you caulk. Make sure you give the area 10-15 minutes to dry afterward so you won’t seal in moisture.

2. Get your caulking gun ready by cutting the tip of the cartridge of caulk at a 45-degree angle and inserting the tube into the gun. If you haven’t used a caulking gun before, do a practice caulking on a newspaper or paper towel so you can get a feel of what to expect before caulking a door or window. We’d also recommend starting with a less prominent door or window until you’ve got the hang of it.

3. Hold the caulking gun at a 45-degree angle to your dry, clean edge that you will be filling. Using a “pulling” motion, hold the gun at a consistent angle and slide the tube nozzle along the joint while pulling the trigger of the caulk gun to apply the material. You know you’ve got the right angle when the caulk is immediately forced into the crack as it comes out of the tube. Try to avoid stops and starts by caulking in one straight continuous stream.

4. Push the caulk into the crack. This is called “tooling”. Once you’ve covered 2-3 feet of the surface with a bead of caulk, dampen your finger (or spoon, piece of wood or foam paintbrush if you don’t want the material to touch your hand) and glide over the bead, pushing the caulk into the crack and force the caulk deeper into the crack you’re filling.

5. Use a damp rag to clean up any mistakes or wipe up excess caulk. Do this immediately because it will be much harder to clean up after it has dried.

6. Allow the caulk to dry according to the directions on the package. It usually takes about 24 hours for the caulk to fully cure, but can depend on air temperature and humidity.

You are now on your way to a warmer house and energy savings!

Related: How to get your furnace ready for winter

Source: | Caulking photo by Courtney Richardson