Municipality guide
This section contains basic information of passive houses for municipalities.
Energy efficient urban structure
A master planner can greatly influence on the energy demand of the neighbourhood. The ways and means to promote urban energy-efficiency by master planning are compactness of the area and building structure, evaluation of the design area and utilization of site characteristics, location and orientation of buildings on individual sites, and minimizing over-shadowing between neighbouring buildings and design areas.
Compact area and buildings
Compactness of the area reduces energy distribution losses, but too dense area may reduce the possibility to utilize solar energy. Compactness of buildings can reduce exposed surface area and hence heating energy demand and consumption in cold climates.
Efficient use of passive energy sources
A Passive House should utilize free energy sources efficiently. In a cold climate passive solar heating may give an important contribution into a building’s energy balance, but at the same time passive cooling need to be addressed even in cold countries. Development plans should thus encourage passive heating and cooling design and shelter from extreme climate conditions.
Benefits of urban passive house neighbourhood
An urban neighbourhood of Passive Houses has many economical benefits. The low power demand is beneficial for the energy infrastructure. Also, local energy production on the scale of an urban area becomes a feasible option because of the low energy demand. While the regulatory and even voluntary actions have started to decrease the heating energy demand in many countries, consumption of electrical energy is still increasing.
A Passive House has minimized heat losses, and thus a larger share of building's heating energy can be covered economically by passive solar gains (mainly through windows). By optimising the site and buildings for passive solar energy, a neighbourhood's energy demand can be reduced by approximately 15 - 30%. The remaining energy demand can then be covered by active solar systems or other renewable sources.
Passive House is the most energy-efficient measure
The end use of energy in a neighbourhood can be described by the total annual heating, cooling, electrical and other household energy consumption and their peak demands. A Passive House represents the most efficient energy saving measure on the individual building and neighbourhood scale.
Master Planning
Master planning of an energy-efficient Passive House neighbourhood includes the basic master planning procedures as any master plan: site analysis, climatic analysis, topography, and slope analysis.
Site layout
The way in which a building is sited will have a major effect on its energy efficiency. For optimal master planning this refers to:
• Use of southern orientation of buildings for passive solar heating. Optimum locations are sunny southern sides of valleys where the temperature balance can become positive helping for reduced heat consumption of buildings.
• Avoidance of placing buildings in valleys because they can gather cold air during nights and the mean temperature will thus decrease.
• Avoidance of creating cold air pockets with long or even curved buildings placed unconsidered on slopes.
• Avoidance of placing buildings on shady places like northern slopes or the north side of dense forests or high buildings close to them.
• Utilization of sunshine also for increasing the pleasantness of yards and public urban spaces.
Climatic, topography and slope analysis
Climatic analysis of a site shows the planner to what extent air temperature, solar radiation, air movement and relative humidity affect on buildings’ energy demand.
In the northern hemisphere, south facing facades receive the greatest amount of solar radiation. The location of buildings on south facing slopes increases the number of buildings that can utilise solar energy, but it is as important to take care of solar protection to avoid overheating during summer.
Optimized urban structures
Passive houses perform the best in optimised urban structures that enable efficient use of energy-saving technologies. Both passive solar heating and passive cooling should be included, since high solar irradiation in winter and low irradiation in summer contribute for a building’s low energy demand. This also defines the extent to which the concept can be applied in various settlements.
Density
Density of the urban development is crucial for a Passive House settlement. The houses should have appropriate distances, or the building height should increase towards North. Flat areas and gentle south-facing slopes are the most prominent design areas for passive houses. However, Passive House concept should be used especially on north facing protection to avoid overheating during summer. Slope analysis gives preliminary information on settlement density and building sites that serve for overall energy performance of the neighbourhood.
Energy efficiency by master planning
A master planner’s possibilities to influence on the energy demand of a neighbourhood are as follows:
- Compactness of the area (gross floor area/design area): reduced district heating network losses
- Compactness of the structure (ratio volume-surface factor): tall apartment building (V/A 0,3) compared to houses in a row allows for approximately 20% less consumption for heating.
- Optimized orientation of buildings towards south: approximately 15% less consumption for heating possible
- Optimized solar irradiation: no shading vs. shading houses in a row; estimated 10% less consumption possible
- Roofs for active solar use by optimum south facing solar panels: estimated 10% to 15% less consumption for hot water possible
- Decision about building standard: Passive Houses compared to the national building code allows for at least 75% less space heating consumption.
For further information please click www.europeanpassivehouses.org