Fixit: Caulking can mean warmer home, lower bills

It's fall and that means it's time to caulk. Filling holes may be the last thing you want to do on a fall weekend, but time spent caulking now will pay off in dollars saved and fewer shivers come winter.

The U.S. Department of Energy says that properly sealing cracks and gaps in your home can significantly reduce heating costs and improve your home's durability. Those very small cracks can seem insignificant, yet they add up to lots of lost energy, and you can stop that with caulk.

Outdoor Caulking 101 What to use: Selecting the right caulk may be the hardest part of the job. Visit any home or hardware store and you'll see a confusing array of caulks: acrylic, silicone, siliconized latex, etc.

You can avoid confusion by remembering what's needed outdoors: caulk that is airtight, waterproof, flexible enough to withstand temperature extremes without cracking, and -- because you don't want to do this regularly -- long-lasting. Silicone caulk is all of the above.

Indoors, acrylic and other water-based caulks are fine, but they will shrink, crack and deteriorate when exposed to the elements. Even if the label says "siliconized" or "plus silicone," these caulks won't work as well as 100 percent silicone, said Brian Holden, with Momentive Performance Materials and GE brand caulks.

Unlike water-based caulks that clean up with soap and water, silicone caulk requires a solvent, such as paint thinner, for cleanup. And while many silicone caulks cannot be painted, some can, such as GE Silicone II XST (paintable formula).

Where it goes: Obviously, any place where you can see light sneaking out of the house when it's dark outdoors, or light leaking in when it's dark inside needs caulk, said Holden. As you walk the perimeter of your house, take note of these caulk-worthy areas: around windows, doors, dryer vent, cable and telephone entry points and where the house meets the foundation. More information on where to seal is at www.stoptheshivers.com.

To dispense the caulk, you can usually push or pull the nozzle along the crack, with advantages to each method. Practice on scrap boards to perfect your technique and avoid messy mistakes. That's especially important with silicone caulk, which can be challenging.

Other tips

• Remove any old caulk first, using a putty knife or razor blade. Clean the area with a stiff brush or household cleaner and let dry.

• Determine how large a bead you need for the job and cut the caulk tube nozzle accordingly. The farther from the tip you cut, the bigger the bead.

• Hold the caulk gun at a 45-degree angle to the surface. Release the trigger immediately when a bead is done and have rags handy for wiping.

• Caulking typically works best in temperatures above 45 degrees.

Cautious caulking

• Mind the size of the hole. Gaps and cracks that are smaller than half an inch can be filled with caulk, spaces of a half-inch to 3 inches should be filled with spray foam. For a hole bigger than 3 inches, insert rigid foam insulation and then caulk the edges.

• Free guides on how to caulk and weatherstrip are available at www.commerce.state.mn.us. Type "caulking" into the search window.

• CAUTION: Although caulking stops air leakage, which can make you feel warmer and save energy, it also can affect the operation of your home's fuel-burning equipment such as the water heater, furnace and fireplaces. Do not block fresh-air intakes for these appliances, and be sure your carbon monoxide alarms work. For more information on proper indoor ventilation, go to www.commerce.state.mn.us and and type "ventilation" into the search box.