Passive House Design

“For us, the quality of the building experience is as important as the quality of the final product.”

The Passive House design concept is a comprehensive approach to cost-effective, high quality, healthy, and sustainable construction. It seeks to achieve two goals: minimizing energy losses and maximizing passive energy gains. Simple enough. But achieving these goals has led to extraordinary results – a Passive House uses up to 90% less energy for space heating and cooling than a conventionally constructed house.

The Passive House design standard is the world’s most rigorous standard for energy-efficient construction, and Lamar Valley Craftsman is a Certified Passive House Builder with the Passive House Institute.

To achieve this, Passive House design employs seven principles. The result? All heating needs in a typical Passive House can be met with a heater the size of a hair dryer. Heat from people, lights, appliances and the sun does the rest. Working with a Certified Passive House Design Consultant can optimize the right design for you and your new home project.

Passive House Design Principles

Superinsulate

This concept is no different than putting on extra clothes in the winter to help keep your body comfortable. Insulating the outer shell or building envelope of the passive house slows heat transmission and maintains the contents at a relatively constant temperature. Warm contents stay warm, cool contents stay cool. When done in conjunction with all the other strategies outlined in the passive house recipe, your home will never fluctuate in temperature more than a few degrees over the course of the year.

Thermal Bridge-Free Construction

To maintain consistent, comfortable temperatures wall assemblies must not only be well insulated, but free of thermal bridges.

What is a Thermal Bridge? A thermal bridge is an area of extreme heat transfer caused either by a conductive material crossing through an insulation layer or a geometric transition in the thermal boundary.  Commonly found at studs, plumbing penetrations, steel beams, and balconies, thermal bridges can significantly reduce the overall R-Value of an assembly.  Passive House buildings are thoughtfully designed to eliminate thermal bridges, thereby mitigating energy loss.

Airtight Construction

The airtight layer (ATL) is one of the most important components of Passive House design and construction and is probably the most difficult to achieve.  Air leakage through a building assembly not only results in energy loss, but more importantly, it can compromise the durability of a structure by trapping water vapors in an assembly.

Mitigating air leakage is the most cost effective measure of reducing energy loss and is the “secret sauce” of any Passive House building. Passive House Certification requires buildings to achieve air leakage no greater than .6 ACH at 50 pascals of pressure.

Did you know? Air movement accounts for more the 98% of water vapor moment in a building assembly. While a one-half inch hole in a wall assembly can introduce more than 30 quarts of water, only 1/3 quart will be lost through diffusion.

High Performance Mechanicals with Energy Recovery

Traditionally, inefficiencies in the building envelope are compensated for with large mechanical systems that are expensive and prone to failure.  Passive House buildings have extremely low energy demands, saving owners capital upfront and drastically reducing operating costs.

In addition to smaller mechanicals, Passive House buildings feature mechanical ventilation systems with heat and energy recovery, which are also referred to as HRVs.  Quite simply, these units are the lungs of any passive house building, constantly supplying fresh filtered air to the home.  HRVs not only provide higher indoor air quality, they also provide moisture management, dramatically improving durability and comfort.

Energy Saving Windows & Doors

In conventionally constructed buildings, windows are one of the greatest areas for both air leakage and energy loss. Passive House buildings specify high performance, specially designed windows and doors to eliminate this concern.

With proper orientation and strategic placement, Passive House windows actually become a significant part of a building’s heating system.  Typically, Passive Homes employ triple glazed units with thermally broken spacers. These windows are highly impressive machines that become an asset in the performance of your home versus a liability.

Passive Solar Orientation

Passive House projects are strategically oriented to take advantage of a building’s natural environment.  Before construction, every Passive House is carefully modeled using a highly sophisticated dynamic software tool developed by the Fraunhofer Institute in Germany, known to the community as WUFI Passive.

Modeling Software

A passive house is all about energy use and comfort. To verify that the desired performance is achieved, it must be designed for, quantified, and verified throughout construction. Passive House Planning Package (PHPP) is a powerful and accurate energy-modeling tool that helps a designer analyze the architectural design of the project and integrate all elements into the design of the home.

Every detail of the home is entered into the PHPP software and assessed as to how it will affect the energy performance. This includes wall thickness, R- or U-values, thermal bridges, airtightness, ventilation sizing, windows, solar orientation, climate and energy gains and losses. Nothing is left to chance.

When construction commences, the production team doesn’t have to make any field assumptions regarding materials or systems, as all details have been worked out in advance to achieve the Passive House energy goals.