Passive House - Exploded View

Passive House: From European Concept to Colorado Reality

What is the Passive House Concept?

Passive House is a construction concept that seeks to create buildings that are truly energy efficient, comfortable, affordable, and ecological all at the same time.

  • Passive House buildings typically use up to 90% less energy than comparable traditional buildings.
  • Homeowners frequently praise their Passive Houses for their high level of comfort, due to improved ventilation resulting in superior air quality and use of natural solar light and heat.
  • Passive Houses save money over the long haul due their greatly reduced utility bills. Certain aspects of a new Passive House might be a bit more expensive, but parts of the house system will be less expensive. For example, buying more insulation cost a little more money, but in return, a smaller, less expensive furnace and air conditioner can be can now be specified.
  • By definition, Passive Houses are eco-friendly. They use extremely little primary energy[i], preventing emissions from coal or natural gas.

Passive House Origins

The birth of the Passive House concept was in the United States during the energy crises of the 1970’s. The American physicist, Dr. William Shurcliff (member of the Manhattan Project) was an early pioneer. By the 1980’s with the energy crises over, American attention on energy efficiency and the Passive House concept vanished. The German government however, actually learned the lessons of the energy crises and encouraged the development of energy efficient houses, and became world leaders in this field.

In Germany, thousands of passive homes (known as “Passivhaus” in German) have been built over the last 30 years. These “houses” are all types of buildings: single family homes, multifamily apartments, and commercial buildings. In Germany the Passive House Institute (PHI) has been at the forefront developing standards.

Germany has exported the technology throughout Europe and there are now an estimated 40,000 Certified Passive House buildings scattered around Europe. With tens of thousands more buildings that have adopted at least some of the passive house concepts. The proof is in the graph below, notice how much less energy German buildings use today compared to 30 years ago. Unfortunately, cheap Russian natural gas stalled progress for more than ten years. But progress has resumed in recent years. The technology has finally made its way back to the United States.

Specific Energy Consumption Heating (Germany)

US adaption challenges

When the Passive House concept came back to the United States, it was realized that the standards created in Germany were not really suitable for environmental conditions found in the U.S. Let’s consider the differences. The U.S. is geographically a much larger country than Germany. Most of Germany fits into a single climate zone, a temperate continental climate. In the U.S. we have eight distinct climate zones, ranging from the hot, dry desert southwest to the cool, maritime climate of the Pacific Northwest, to the sub-tropical along the Gulf Coast, to very cold conditions upper mid-west and Alaska.

To handle these various climate conditions, the Passive House Institute of the U.S. (PHIUS) created a set of passive house standards that make sense for the different climate conditions in the U.S.

Colorado specific considerations

Here in Colorado, we have four different climate zones. Most of us live in climate zone 5B, relatively cold (in the winter) and dry. As we move higher into the mountains, our climate zone shifts to 6B or 7B (very cold). With a small area of zone 4B in the southeast corner of the state. The “B” designator indicates our dry, semi-arid climate.

What this means is that the home we design for the Denver area will be very different from the home that we might design for Summit County. Your architectural and engineering team will need to pay close attention to these differences in order to meet your goals.

Implementation Examples

For a home in Denver (zone 5B), we will need to consider both winter heating (down to 1°F) and summer cooling (up to 100°F). We’ll need insulation of R-60 in the roofs, with high quality windows and doors. A modern mini-split heat pump is a good choice for heating and cooling.

Up higher in the mountains, say Summit County, architects and engineers need to design homes for colder winters. The design temperature is a chilly -13°F. There is little need for summer cooling in most situations. Radiant floor heating systems are a good choice in Summit County. Most air source heat pump systems don’t work well at such cold temperatures; however, ground source heat pumps can still work well. For the insulation we will need at least R-76 in the roofs, with very high-quality windows and doors.

Bottom line, in Colorado we have multiple very different climate situations that require different solutions. At Delta Energy Solutions, we are not wedded to a single way of building homes. We look at the unique building challenges of each property, considering the unique goals of each client and design the home to meet those challenges and client goals.

To schedule a free 30-minute consultation, please contact us:

 

(1) Primary energy: Energy sources that present in the natural world, the source can be either renewable or non-renewable. Examples include; coal, natural gas, crude oil, sun, wind, geothermal.

Related Posts