Urban Natural Homes January 8, 2016

Baby it’s Cold Outside, Part #1: The Building Envelope


With winter fully upon us and as the thermometer dips, one’s thoughts can’t help but turn to the ever increasing energy bill. With today’s technology there are a plethora of new systems, appliances, gadgets and resources that can help lower that bill; but the single most effective thing you can do to conserve energy in your home is to examine and improve your home’s building envelope. “What is a building envelope?” you ask? The building envelope is comprised of the below-grade systems (foundation, basement and/or crawlspace), the exterior walls, the fenestration system (windows and doors) and the roof. It is the building envelope that divides conditioned space—i.e., intentionally heated and cooled space—from unconditioned space. The building envelope can be significantly improved through projects such as replacing doors and windows with more energy-efficient models or adding to/upgrading the current insulation; which we will take a look at in Part #2 of this series. However, the first place to start in improving the building envelope is simply to examine it and fill in any leaks. Common problem areas to check for gaps or holes in the building envelope include:

  • Plumbing penetrations through insulated floors and ceilings
  • Chimney penetrations through insulated ceilings and exterior walls
  • Wiring penetrations through insulated floors, ceilings and walls
  • Door and window frames
  • Mail chutes
  • Electrical and gas service entrances
  • Cable TV and phone lines
  • Outdoor water faucets
  • Dryer vent outlets
  • Brick, siding, stucco and the foundation
  • Vents and fans

In order to seal these problem areas, select a sealant with the size of the crack or hole in mind:

  • Cracks less than ¼”: Use caulking
  • Cracks more than ¼”: Use expanding foam sealant or crack filler flexible foam material
  • Larger openings: Use rigid foam insulation, fiberglass insulation, roof flashing or a silicone sealant

Hiring a pro to do an energy audit can also be an excellent idea, especially if you’re not the type to go around your house crawling on your hands and knees looking for leaks. For more information on energy audits, and how you can potentially get reduced rates on an audit thorough King County programs, see my April 2012 article, “The Energy Audit: Do You Know How Energy Efficient Your Home Is?” The more thorough audit that includes performance tests such as the Blower Door Test is the one that can help you to identify leak issues in your home.