Passive House FAQs
Is the passive house approach only for houses?
No! The approach can be successfully applied to any type of building, including skyscrapers.
The term passive house is something of a misnomer -- although plenty of single-family homes have been built to the passive house standard, the approach is increasingly being applied to multifamily apartment buildings and large scale commercial buildings as well. As a result, the term passive building is gradually coming into more common usage, as it's a more accurate term than passive house.
Does it cost a lot more to build a passive building compared to a conventional equivalent?
Currently, a passive house typically costs about 5-10% more than a conventional home. Larger projects benefit from the economy of scale: a multifamily passive building typically only costs 0-3% more than a building built to an energy star baseline. In general, the larger the building the less of a cost difference there is. Also, as more large-scale window and door manufacturers bring high-performance products to market, economies of scale are expected to drive down costs.
What is it like to live in a passive house? Can you open the doors and windows?
Passive houses and buildings are extremely comfortable in all seasons. That's because there are no drafts, temperature variance is extremely narrow (even near doors and windows), and active, balanced ventilation makes for superb indoor air quality. And yes, passive house owners open their doors and windows just as they would in a conventional home.
Passive buildings are super airtight – what about moisture and mold problems?
Passive buildings do require an extremely airtight building envelope. Combined with super-insulation, this approach dramatically reduces temperature variation, which also prevents condensation and mold issues. The constant, low-level ventilation also helps prevent moisture problems in addition to maintaining excellent air quality.
That being said, potential moisture issues must be carefully addressed at the design stage. That's why it's important to work with a Certified Passive House Consultant (CPHC®). CPHCs are trained to accurately model building performance and to identify and address potential moisture issues with a variety of techniques.
Do passive buildings all have to look the same?
Nope! Although many early passive homes used an austere European style, passive design does not dictate aesthetics. PHIUS has certified projects in dozens of styles ranging from Cape Cods to traditional Four Squares, contemporary multifamily projects, and more.
|Sample R-Value Guidelines**||R-Value Ranges|
|Miami, FL; Honolulu, HI||1||19 - 27||44 - 60||2ft R-8 vertical perim|
|Jacksonville, FL; Phoenix, AZ||2||19 - 27||30 - 70||uninsulated|
|Charleston, SC; Sacramento, CA||3||15 - 31||30 - 60||uninsulated or
2ft R-8 vertical perim
|San Francisco, CA||Marine 3||19 - 23||30 - 38||4ft R 8-20 vertical perim|
|Baltimore, MD; Amarillo, TX||4||31 - 51||49 - 80||2-4ft R 8-20 vertical perim|
|Salem, OR; Seattle, WA||Marine 4||31 - 43||60 - 70||4ft R-20 vertical perim
or whole-slab R-20
|Providence, RI; Flagstaff, AZ||5||31 - 43||60 - 70||4ft R-20 vertical perim
or whole-slab R-20
|Burlington, VT; Billings, MT||6||39 - 51||70 - 90||whole-slab R20-28|
|Duluth, MN; Edmonton, AB||7||49 - 65||80 - 90||whole-slab R28-40|
|Fairbanks, AK||8||89||120||whole-slab R-40|
Generated from PHIUS+ 2015 studies
Pertains mainly to single-family buildings
Actual R-values will vary by project