Category Archives: PH Concept

Passive House

Outrageous energy-efficiency …sublime comfort.
Reduce energy consumption by 90% and enjoy amazing comfort with a Passive House. Interior temperatures are always even and constant …yes, including in front of windows… and the air is always fresh and clean.

One Sky Homes has fully embraced The Passive House concept and incorporates the Passive House standard in it’s high-performance homes including Zero Energy Home designs. One of only a handful of building design/construction professionals in the Bay Area rigorously trained in PH methods and implementation practices, OSH is a Certified Passive House Consultant (final certification pending) under the authority of the Passive House Institute US.

The designation ‘Passive House’ is a building standard and construction concept that acheives the highest standard in energy-efficient construction available in the world today. Originating in North America in the late 1970’s as the “Super-Insulated House” , the concept was further developed in Northern Europe in response to rigorous energy standards for new buildings mandated by the Swedish government in 1988. In 1990, the first prototype was designed and built by  Professors Bo Adamson and Wolfgang Feist in Darmstadt, Germany. Today, there are an estimated fifteen thousand Passive Houses in Europe, mostly in Germany and Austria.

Heat your home with a hair dryer

The Passive House standard is a design methodology that focuses on super-insulated, airtight construction, maximizing useful solar heat gains while minimizing unwanted gains during summer, using continuous fresh air ventilation with heat recovery to reuse internally generated heat, and installing high performance windows and doors to minimize heat losses and maximize occupant comfort.

For space heating and cooling, a Passive House typically uses up to 90% less energy than a conventionally constructed home meaning that it can often be heated with the energy equivalent of a hair dryer. There is typically a significant reduction in the size and cost of the heating system.

These exceptional energy savings are achieved by following seven specialized design and construction principles:


To block or slow heat transmission and maintain a relatively constant temperature inside a building, it must be incased in a heavily-insulated shell or envelope. The envelope of a Passive House includes the wall, roof and floor assemblies insulated to a level appropriate for the particular climate where the house is located and which achieves specific energy consumption standards.

Eliminate Thermal Bridges

Heat quickly finds its way out of a building in a path of least resistance leading to serious heat loss. The path is easily created from an area of higher thermal conductivity such as edges, corners, connections and penetrations. The goal of Passive House construction is to block thermal bridges by isolating them (thermal break).

Infared image of a wall protraying cold areas caused by the studs acting as a thermal bridge (dark lines).

Make It Airtight

The goal of an airtight environment is to minimize heat losses. Drafts, either hot or cold, make a major contribution to wasted space conditioning.  Also, penetration of the building by warm moist air can cause structural damage by condensation inside the wall. The Passive House standard achieves airtight construction by wrapping an intact, conitinuous layer of materials around the entire building envelope.

Specify heat recovery ventilation.

Traditional HVAC systems are dramatically simplified, down-sized and in some cases eliminated in a Passive House. Instead, Interior Air Quality (IAQ) is maintained by a smaller ventilation system, referred to as a fresh-air furnace. This heat/cold recovery ventilator retains energy that has already been generated in the house instead of venting it to the outside. Measured amounts of fresh air circulate inside the house while at the same time exhausting stale air from the house. A Passive House in a warm climate is ventilated with high efficient energy recovery ventilators (ERVs) or in cold climates, heat recovery ventilators (HRVs).

Specify high-performance windows and doors.

Windows and doors significantly affect heat loss in standard construction. In the Passive home, insulating value determines which windows and doors will be used in construction. Major developments in building construction include the development of fully operational, high performance, triple-glazed windows. The gaps between window panes are filled with inert gases like Argon or Krypton which provide better insulating values than air.

Optimize passive-solar and internal heat gains.

Many issues confront the Passive House designer when considering the orientation of a new structure and how it will affect its energy gains and losses. As sunlight falls on or in a house it is converted to heat so the first consideration for a designer are areas in a house that will be used most frequently by the occupants such as living rooms, dens/offices and bedrooms. These areas should be located on the south-facing side of the structure, while garages, laundry rooms and storage areas should be situated on the house’s north side.

Passive solar heat is generated through windows that must be oriented for optimal solar gain. Roof eves and proper shading can assist in preventing excess solar heat gain while still allowing heat gain from low winter-time sun angles. View lots and landforms can challenge even the most creative designers if they are not located in the optimal place for a passive house design.

Model energy gains and losses using the Passive House Planning Package.

Sophisticated simulations were once required to calculate energy balance in buildings but now The Passive House Performance Package (PHPP), a spreadsheet structured design tool, assists designers and architects to reliably calculate heating energy balances, heat distribution and supply and energy demand using managable data input. With reliable accuracy, the PHPP software program is able to describe the thermal building characteristics of an unconstructed passive house design.