Passive House History

Passive Solar Design

Passive solar design is hardly a new concept. From Wikipedia:

“The techniques of passive solar building design were practiced for thousands of years, by necessity, before the advent of mechanical heating and cooling. It has remained a traditional part of vernacular architecture in many countries. There is evidence that ancient cultures considered factors such as solar orientation, thermal mass and ventilation in the construction of residential dwellings. Fully developed solar architecture and urban planning methods were first employed by the Greeks and Chinese, who oriented their buildings toward the south to provide light and warmth”.

Before grid electricity, oil and gas, designers often had to utilize passive energy sources to achieve comfort. The ancient Greeks planned whole cities in Greece and Asia Minor such as Priene, shown in the illustration, to allow every homeowner access to sunlight for winter warmth. By running the streets in a checkerboard pattern east-west and north-south every home could face south.

During the fifth century BC, many Greek cities faced severe heating fuel shortages (due to deforestation on the thin soils of their Mediterranean environments). Fortunately, an alternative source of energy was available - the sun. Archaeological evidence shows that a standard house plan evolved during the fifth century so that every house, whether rural or urban, could make maximum use of the sun's warm rays during winter.

As the Greek philosopher Aeschylus wrote more than 2000 years ago: "Only primitives & barbarians lack knowledge of houses turned to face the Winter sun."

Looking at modern Canadian housing, you might feel we could add Canadian planners and developers to this group of “primitives and barbarians”, since virtually every subdivision built in Canada in the past 40 years completely disregards solar exposure as a significant design component.

Passive Solar Design in North America

North American solar architecture began with its indigenous heritage. For example the passive solar town of Acoma, New Mexico, built by the Pueblo Indians in the 12th century AD (and continuously inhabited since then) serves as an excellent example of their sensitivity to building with the climate in mind.

Spaniards who settled in the American southwest often built to take advantage of the winter sun: they aligned their homes east to west so the main portion of the house faced south.
Early European settlers in New England considered the climate when they built their homes. They often chose "saltbox" houses that faced toward the winter sun and away from the cold winds of winter. These saltbox homes had a large south-facing façade where most of the rooms were placed, and only one storey at the rear of the building. The long roof sloped steeply down from the high front to the lower back side, providing protection from cold winter winds.

The oil crises of the 1970s renewed interest in passive solar designs, with numerous prominent building projects and publications appearing across the U.S. and Canada. In general these “passive solar” houses performed poorly, with many of them experiencing wide interior temperature fluctuations, high construction costs, moderate comfort levels, drafts and higher-than-expected heating bills.

We now know that these passive solar buildings from the 1970s and 1980s were often designed improperly, and fitted with building components (e.g. windows) of insufficient quality. Often such buildings were overglazed, full of serious thermal bridges and they incorporated excessive, expensive thermal mass. Such problems are not found in today’s Passive Houses.

First Passive Houses

Although the Passive House approach to construction has been developed and refined in Europe over the past 20 years, it’s been said that the first real Passive House ever built was the Saskatchewan Conservation House designed and constructed in Regina, Saskatchewan in 1977 by a team including researchers from the National Research Council and Saskatchewan Research Council.

From a 2011 perspective it can seem ironic that Canada was a world leader in energy efficient construction practice during the late 70’s and early 1980s, but we then seemed to lose interest, and certainly failed to incorporate any of the successful features of the Saskatchewan Conservation House into later residential construction codes.

The first so-called Passive Houses were designed and built in 1990, in Darmstadt, Germany. These houses incorporated R&D from many parts of the world, including Canada’s R-2000 program and the Saskatchewan Conservation House, yet they differed significantly from other low-energy houses.

These units confirmed that it was possible to build homes in a cool northern climate which simply don’t need a conventional heating system in order to maintain excellent year-round comfort and high levels of indoor air quality.

This represented a ‘Factor 10’ improvement in building energy performance, compared to standard Building Code construction. It is achievable only through dramatic improvements in the thermal and airtightness properties of the building envelope, and it requires significant changes to normal construction practice.

The concept of ‘zero-energy’ buildings was already well known at this time, and many had been built. But such buildings must incorporate expensive renewable energy systems, therefore Net Zero houses have always been unaffordable for the average homeowner, and will likely remain so.

Instead the Passive House approach aims for an optimal economic investment combined with the highest levels of comfort and indoor air quality. Even at today’s relatively low energy prices a Passive House is the cheapest house you can build in Canada over its lifecycle, if you take all costs into account.

In 2008 the European Union passed a resolution calling on each European member state to adopt the Passive House Standard by 2016 for all new construction and major renovation projects. Ultimately this resolution will alter the construction industry in all parts of Europe, as the continent recognizes the need to build for long-term economic benefits, improved indoor air quality and personal and national energy security.

The Passive House movement has built great credibility across Europe because of the growing number of successful projects in almost all countries, and the realization that this is an optimal economic investment. As one architect has stated:

“Every Passive House building is a savings factory offering future security against rising energy prices”.