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In many homes across the state, air infiltration causes drafts and a chilly feeling in some rooms during the cold weather months. Adjusting your thermostat won’t stop the drafts, but sealing hidden cracks and openings will.

By stopping drafts at their source, you’ll stay warmer at lower thermostat settings, use less energy and reduce your utility bills. As a bonus, the air leaks you plug now will help your air conditioner cycle less often next summer.

It’s not easy to caulk and weather-strip the offending spots around your home’s exterior when winter’s raging outside. However, you can stop many leaks from inside – especially the ones that transfer cold air from room to room or from your basement through the house and into the attic.

You likely already know the location of many of the cold air leaks in your home, but you can use your hand or a lighted incense stick to confirm their existence. Before you start, note that caulks and other sealing materials generally are formulated for application at temperatures above 40 degrees. If you must repair a large interior air leak (or one on an outside wall) during low outside temperatures, be sure to buy a caulk or sealant specifically designed for that purpose.

Start in the living spaces

  • Although many points of air infiltration can originate elsewhere, begin your search in the most-used areas of your home. This will have the greatest impact on your family’s comfort, because these are the leaks and cold spots they feel every day.
  • Caulk around frames for exterior doors and around trim and baseboards where they meet the wall and floor with an interior-grade caulk. Use a clear-drying caulk for hardwood or tile floors and trim with natural wood finishes – and paintable caulk for painted trim and carpeted floors.
  • Seal cracks between the walls and window frames and trim, especially under the windowsills.
  • Around the moving parts of windows, use a strip-away, nonpermanent caulk or cover the entire window with an inexpensive plastic film window insulating kit.
  • Install foam gaskets on all electrical switches and outlets – even on interior walls. Be sure to turn off the power to the area where you’ll be working first.
  • Use child-safety plugs to minimize the amount of cold air coming through the sockets in outlets.
  • Recessed lights and bathroom fans can poke into attic insulation and create a pathway for air leaks, so seal around them from below with flexible, high-temperature caulk.
  • Cracks, missing plaster and exposed lath indicate a direct hole into wall and ceiling cavities. Repair these spots with plaster or cover them with new drywall.
  • In the kitchen, caulk or use spray foam around kitchen cabinets, as well as drains, water pipes and electrical lines in conduits where they enter the wall or floor. In bathrooms, seal the pipes and areas around medicine cabinets, bathtubs and showers too.
  • Tightly seal a whole-house attic fan with a window insulating kit or other material.
  • If you have an attic hatch, make sure it fits tightly and is backed by insulation. Weather-strip the edges of the access hole and build a simple wood box to hold insulation on the backside of the hatch. As an alternative, purchase an insulated hatch cover.

Head down to the basement

Air leaks that start in the basement can work their way upstairs in several ways, so stop infiltration at its source. Taking a tour of your basement when it’s sunny outside will help you spot obvious leaks around the foundation and exterior walls. Before you caulk, be sure to vacuum dusty areas or wipe them clean to promote adhesion of the sealant.

  • Caulk any crack between the sill plate and foundation wall using a material that works well with masonry. Use caulk to fill any cracks between the sill plate and band joist too.
  • The chase for a plumbing stack may run inside the walls of your home, from the basement to the attic, with openings at each floor where the pipes branch off. If the chase isn’t much larger than the pipes, seal it with expanding foam. For larger chases, use drywall, wood or rigid foam – and caulk or foam all around the edges.
  • Seal the hole where the bathtub drain comes down – and any other holes for plumbing or electrical wiring in the basement ceiling – with caulk or foam. You may need to use a filler material for larger holes.
  • If your home has forced-air heat, there may be large cracks or gaps where the ducts pass through the ceilings, floors and walls. Caulk or foam where the metal duct opening and the ceiling, floor or wall meet. Also seal joints in the ducts with duct mastic. (Duct tape will not stay stuck for long!)
  • Using a caulk that works well with masonry, fill cracks where the frames of basement windows are set into the walls. Windows that aren’t used for summer ventilation or as fire exits can be caulked shut permanently. For operable windows, use a strip-away, nonpermanent caulk you easily can remove in the spring.
  • Weather-strip the edges (and insulate the back) of the hatch or door to the crawl space.  


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