What makes a building passive ?

Sample R-Value GuidelinesR-value ranges
ZoneExample CitiesWallCeilingSlab
1Miami, FL or Honolulu, HI19 - 2744 - 602ft R-8 vertical perim
2Jasonville, FL or Phoneniz, AZ19 - 2730 - 70Uninsulated
3Charleston, SC or Sacramento, CA15 - 3130 - 60Uninsulated, or 2-4ft R-8 vertical perim
Marine 3San Francisco, CA19 - 2330 - 804ft R8-20 vertical perim
4Baltimore, MD or Amarillo, TX31 - 5149 - 802-4ft R8-20 vertical perim
Marine 4Salem, OR or Seattle, WA31 - 4360 - 704ft R-20 vertical perim, or whole-slab R-20
5Providence, RI or Flagstaff, AZ31 - 4360 - 704ft R-20 vertical perim, or whole-slab R-20
6Burlington, VT or Bilings, MT39 - 5170 - 90whole-slab R20-28
7Duluth, MN or Edmonton, AB49 - 6580 - 90whole-slab R28-40
8Fairbanks, AK89120whole-slab R-40
* Actual values will vary by project

Hitting the Performance Target

A Certified Passive House Consultant (CPHC®) employes a combination of principles to achieve the PHIUS+2015 performance goal

Super Insulation

Continuous insulation at high levels throughout the entire envelope. Passive buildings have thicker-than-usual walls.

Elimination of thermal bridges

Any place a building component penetrates the envelope from the exterior to the interior is called a thermal bridge. In conventional buildings, multiple bridges add up to significant energy lost. In passive buildings, they are designed out.

Airtightness

Passive building envelopes are much tighter than conventional code building, preventing energy loss through infiltration, and ensuring building durability.

High performance windows/doors

Passive buildings use high performance windows and doors that minimize energy loss.

Optimize solar gain

Through orientation and shading methods, designers get the most out of passive solar heating in heating season, and minimizes its impact during cooling season.

Controlled Ventilation

In an airtight building, mechanical ventilation is designed to assure continuous fresh air. Typically, the designer employees a balanced heat and moisture recovery ventilator. Energy Recovery Ventilators (ERVs) use heat exchange technology that allows intake air to scavenge energy from the already-conditioned exhaust air.

The result – a building that provides:

  • Superior comfort and indoor air quality
  • Low energy bills
  • Resilience – in a power outage passive buildings maintain comfort for days
  • Durability – designed to minimize risk of moisture and other issues

Content & Images credit by Passive House Institute US

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