In 1988, two physics professors began discussing the scientific components that might lead to better energy efficiency in building construction. Bo Adamson from Lund University in Sweden and Wolfgang Feist from the Institut für Wohnen und Umwelt in Germany had read the research, dating back to the 1970s, that suggested it was possible to construct a low-energy building that was designed to exploit passive solar technologies and establish a comfortable indoor temperature with a low-energy requirement for heating or cooling.
They coined a German term to describe this process. It was “Passivhaus.” As this school of thought spread to English-speaking countries, like the US and the UK, these design theories came to be known as “Passive House.” In many ways, this approach fundamentally changed the way architects, construction engineers, and builders viewed energy efficiency in homes, commercial buildings, schools, and all other structures.
As Feist noted later, “Passive House is a building standard that is truly energy efficient, comfortable, and affordable at the same time. Passive House is not a brand name but a tried-and-true construction concept that can be applied by anyone, anywhere.”
What This Means for You — Energy efficiency is among the most discussed topics for homeowners, residential and commercial builders, and architects. Why? It impacts the availability of fossil fuel and its pricing. And for everyone on the planet, energy costs have become expensive reminders of the importance of energy efficiency.
Energy efficiency, resulting from innovative construction strategies such as Passive House, relies on building materials that help insulate the structure. For thousands of years, brick has helped shield homes and other buildings from nature’s relentless onslaught. For more information on using brick in your next project, speak to an expert at Acme Brick.
Passive House Construction: More Than a Low-Energy Building
In an interview with Professor Feist, the Passive House Institute highlighted the benefits of construction that uses this standard. He noted:
- Passive Houses allow for space heating and cooling-related energy savings of up to 90% compared with typical building stock and over 75% compared to average new builds. Passive Houses use less than 1.5 liters of oil or 1.5 cubic meters of gas to heat one square meter of living space for a year—substantially less than common “low-energy” buildings. Vast energy savings have been demonstrated in warm climates, where typical buildings also require active cooling.
- Passive Houses make efficient use of the sun, internal heat sources, and heat recovery, rendering conventional heating systems unnecessary throughout even the coldest of winters. During warmer months, Passive Houses make use of passive cooling techniques such as strategic shading to keep comfortably cool.
- Passive Houses are praised for the high level of comfort they offer. Internal surface temperatures vary little from indoor air temperatures, even in the face of extreme outdoor temperatures. Special windows and a building envelope consisting of a highly insulated roof and floor slab, as well as highly insulated exterior walls, keep the desired warmth in the house or undesirable heat out.
- A ventilation system imperceptibly supplies constant fresh air, resulting in superior air quality without unpleasant drafts. A highly efficient heat recovery unit allows for the heat contained in the exhaust air to be reused.
The 5 Classical Principles of Passive House
Due to its history in the construction industry—more than 130 years—Acme Brick customers have had sustainability on their radar screens for a long time. However, the Passive House standards have moved that “blip” on the screen to something exponentially larger.
There are five principles that enable this type of construction to enhance energy efficiency.
- Continuous Insulation
Buildings using Passive House standards are wrapped in a thermal barrier that keeps them warm in the winter and cool in the summer.
- No Thermal Bridges
Meticulous attention is paid to any construction details that might allow heat or cold to bypass that thermal barrier.
- Airtight Construction
This construction requires an airtight construction that acts as a “windbreaker” to stop air from penetrating to the inside.
- High-Performance Windows and Doors
The windows and doors in this type of build must be airtight, thermally broken, and insulated to manage solar gain.
Fresh Air Ventilation with Heat Recovery
These elements create “havens” of clean air and energy efficiency.
Click here for a less than 5-minute look at “Passive House 101”
It is no coincidence that the first principle noted above was “continuous insulation.” It is the most important part of the equation. Without this factor, Passive House is only Partial House.
Brick Construction + Passive House Design = Energy Efficiency
Going back to ancient times, long before Passive House was contemplated, builders recognized the durability, low maintenance, and classic appearance of brick construction in homes, public buildings, and commercial buildings. Over the centuries, as populations and the homes to shelter them increased, the demand for energy necessary to make these structures livable skyrocketed. Brick continued to be a popular choice for construction, partially because of its insulation value. This is due to its “thermal mass.”
The insulating property of buildings is very simplistically described by “R-value,” which is the resistance to heat flow in “steady state” conditions. The practical reality is that climates are not so steady, and structures are subject to more complicated conditions.
It’s more important to consider exterior cladding materials that have superior thermal mass benefits. Thermal mass is the material's capacity to absorb and store heat. Dense materials such as clay brick, stone and concrete have superior thermal mass capabilities.
As was noted in this article, “If you live in the Southwest US and it’s August, you will probably have your AC running non-stop. During the day, a clay brick wall will slowly heat up, but the temperature on the interior side of the brick wall will never reach the hottest temperature of the day. This is known as the ‘dampening effect’ because it heats up so slowly. When this occurs, a ‘thermal lag’ happens to the structure. The dampening effect and thermal lag are the two components that make up thermal mass.
“Other building materials may be better in ‘steady state’ conditions, but no building material has the superior thermal mass that a clay brick has. This thermal dampening can mean that less powerful air-conditioning (e.g., a 2-ton versus 3-ton unit) is needed, saving the homeowner money.”
The thermal mass of fired clay brick and the space between the exterior and interior walls provide the effective shield—the continuous insulation—required for Passive House construction. This is a critical factor in its effectiveness.
Shelter From the Elements
The challenges of energy conservation, including financial concerns, have encouraged construction engineers to think more creatively. Passive House standards are relatively new and, as such, are just getting the attention they deserve. However, construction materials such as brick have helped homeowners find shelter from nature for thousands of years. As with many “modern” advances, with brick and Passive House, everything old is new again.
If you’re considering building a new home and want energy efficiency, have your architect or builder contact Acme Brick for a quote.