Going Green: Why You Should Build a Passive Home

Solar Decathlon 2007

You know about green homes. You’ve heard about smart homes. But, passive homes? The passive house design was developed in the late 1980s by scientists interested in minimizing building heat loss. The majority of energy used in a home is heat, which is lost through the structure. The Passive House Institute of the U.S. states that the goal of a passive house is to reduce the heating requirements by 90 percent. With green home planning, you’re also planning for ways to (significantly) reduce living costs. If you’re undergoing an energy-efficiency evaluation for your home-building project, learn how and why you should design a passive house.

Energy Efficiency

Passive house are built from the ground up. Passive techniques are rarely used for remodeling projects because the existing structure may not meet the passive home standards.

Although these types of green homes typically don’t have heating and cooling systems, a passive house is designed to:

  • Capture the energy of the sun and retain that energy as much as possible inside the house.
  • Have optimum insulation with nearly air-tight seams.
  • Retain any heat generated by people and equipment inside of the building.
  • Use triple-glazed, airtight windows and skylights; when closed, no air escapes around the openings.
  • Use reflective materials to regulate the amount of sunlight and heat that enters the building.
  • Install windows to face in directions that access the sun.
  • Cool house surfaces with strategic landscaping.
  • Install an energy recovery ventilator to create fresh, conditioned air and a healthy environment. Exhaust fans in the kitchen and bathrooms can also provide additional air movement.

Thermal Bridging & Heat Loss

A concern for passive home building is that heat is lost through thermal bridges. Thermal bridges are where construction materials meet. Heat escapes where they join. Heat is also lost at places where insulation is nailed or stapled to a stud. Maximum insulation is reduced or eliminated when the insulation is compressed by a nail or staple. Discuss with your contractors about techniques that minimize or eliminate thermal bridging.

Passive & Active Solar Energy

Passive home design includes passive and active solar energy. The California Energy Commission defines passive solar as using no mechanical means to control indoor temperature. These homes are built to use the energy from the sun to heat the inside of the house.

They also tend to use active solar panels to produce electricity for the home. Because the heating and cooling needs of a passive house are greatly reduced, it doesn’t need as much electricity. Solar panels can easily generate the power needed for a passive design. In fact, they can generate more than enough.

A story from The News Tribune reported on a passive home that actually gives excess electricity back to the power grid. This recently built home uses solar panels to generate electricity. The amount of electricity the home doesn’t need returns to the local power company. The reimbursement check the homeowners get more than covers their electric bill. So, is a passive home in your future?