A low-energy house is any type of house that from design, technologies and building products uses less energy, from any source, than a traditional or average contemporary house. In the practice of sustainable design, sustainable architecture, low-energy building, energy-efficient landscaping low-energy houses often use active solar and passive solar building design techniques and components to reduce their energy expenditure.

The meaning of the term ‘low-energy house’ has changed over time, but in Europe it generally refers to a house that uses around half of the German or Swiss low-energy standards for space heating, typically in the range from 30 kWh/m²a to 20 kWh/m²a. Below this, the term 'ultra-low energy building' is often used.

PASSIVE HOUSE BUILDINGS

The term passive house refers to a rigorous voluntary standard for energy efficiency in a building by reducing its ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling. Passive design is not an attachment or supplement to architectural design, but a design process that is integrated with architectural design.
 

The Passive house standard requires that the building fulfils the following requirements: 

  • The building must be designed to have an annual heating and cooling demand as calculated with the Passive House Planning Package of not more than 15 kWh/m² per year in heating and 15 kWh/m² per year cooling energy OR to be designed with a peak heat load of 10W/m².
  • Total primary energy (source energy for electricity and etc.) consumption (primary energy for heating, hot water and electricity) must not be more than 120 kWh/m² per year.
  • The building must not leak more air than 0.6 times the house volume per hour (n50 ≤ 0.6 / hour) at 50 Pa (N/m²) as tested by a blower door.