Frequently Asked Questions (FAQs)

19. Low Energy Building - is there a standard?

In a report "Low Energy Buildings In Europe: Current State of Play, Definitions and Best Practice" low-energy buildings are defined as "...typically using high levels of insulation, energy efficient windows, low levels of air infiltration and heat recovery ventilation to lower heating and cooling energy. They may also use passive solar building design techniques or active solar technologies. These homes may also use hot water heat recycling technologies to recover heat from showers and dishwashers."

With the accelerating trend to low energy building throughout the world many terms are currently used to describe the desired end result. This can often create confusion as well as mislead as the there is no global standard and regulations vary from country to country.

A European survey undertaken in 2008 identified:

"...17 different terms in use to describe such buildings used across Europe, among which the terms low energy house, high-performance house, passive house / Passivhaus, zero carbon house, zero energy house, energy savings house, energy positive house, 3-litre house etc. In the relevant literature additional terms such as ultra-low energy house can be found. Finally, concepts that take into account more parameters than energy demand again use special terms such as eco-building or green building."

Such confusion can be understood when comparing the passive house / Passivhaus approach which aims to reduce energy consumption by appropriate design and construction techniques so as to minimize the requirements for heating, cooling and ventilation and the concept of zero net energy with its strong emphasizes on using local generated renewable energy sources to replace grid reliant energy. Both approaches have the same desired outcome i.e. low energy use, but the end result may be totally different in terms of building performance and, occupant comfort and satisfaction.

pub. California Energy Efficiency Strategic Plan Jan. 2011 update

Indeed within the concept of zero net energy there is the energy harvest" versus "energy conservation" debate, as the end result can be achieved with a conventional house with sufficient renewable energy sources or design and construction techniques that minimizes energy usage and requires less renewable energy. The European Council for an Energy Efficient Economy in a review paper titled "Steering through the maze -Nearly zero energy buildings: achieving the EU 2020 target" in Feb. 2011 stated " Despite the excitement over the phrase "zero energy," we lack a common definition, or even a common understanding, of what it means "

A paper delivered at the Renewable Energy Research Conference 2010 Trondheim, Norway called "User Evaluations of Energy Efficient Buildings" by Hauge, Åshild Lappegard; Thomsen, Judith; Berker, Thomas, showed that more education is required to enable people to better understand the concepts and technologies utilized in low energy building. It is also called for long term studies to be undertaken to ensure that such low energy buildings do perform as planned. Education is seen as critical for the success of low energy building world wide and the standardization of terminology and regulations would play a significant part in achieving this.

Currently an emerging de facto standard is the passive house / Passivhaus standard (see faq 17) which originated in Germany in 1988. This is a measurable standard and long term studies have been undertaken of the performance of buildings certified with the standard.