Energy Efficient Buildings
In a nutshell
SEMERGY® is a Web-based building optimization system that supports the planning of energy-efficient construction and refurbishment projects. It allows users to specify the properties of their buildings including size, type and geometry, identifies potential refurbishment options, evaluates the different options, etc. and suggests the optimal renovation solution with respect to energy savings, cost saving potential, and sustainability of building products.


Your Benefits
  • Significant Cost Reductions
  • Informed Decision Making
  • Efficient Energy Efficiency Optimization
  • Legal Compliance
  • Energy Provider
  • Cities
  • Companies
  • Building owners and managers
  • AEC (Architecture Engineering and Construction)
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Have a look at the unique
Web-based and intuitive user interface
Optimisation of energy demand
Extended cost-benefit analysis
Interactive decision support
Custom floor plan
Building shadowing and heating systems
3D Visualisation
Support for the planning of new buildings
Get a detailed overview of all features
Learn more about the
Legal Background
The Directive 2002/91/EC of the European Parliament requires member states to calculate the energy performance of buildings with the overall goal of reducing their energy consumption.

Additionally, the 2008 EU climate and energy package demands Austria to decrease the greenhouse gas emissions by 16% and increase the share of renewable energy sources by 50% till 2020 (basis 2005). With this requirements in mind, Semergy’s goal is to support ongoing EU and Austrian energy saving initiatives by creating an easy-to-use and end-user-friendly decision support system for the determination of a building’s energy performance and the identification of potential improvements. The basis for the energy performance calculation is the Önorm B8110-6 and the OIB-Richtlinie 6 to determine the heating demand with respect to a building’s heat losses (transmission and ventilation losses) and gains (solar and internal gains), supplemented by additional Önorms (e.g. B8110-5 for climate and building usage parameters). The calculation of the heating energy demand with respect to different heating systems with different energy carrier types is based on the Önorm H5056 to determine the heating technology energy demand (i.e., heat losses) to factor in an estimation of the energy saving potentials of updating an existing heating system. Sustainability information of building products is given the IBO OI3 index values.

Energy Efficiency Directive

The 2012 European Energy Efficiency Directive (EED – 2012/27/EU) requires member states to save at least 1,5% of their yearly energy consumption per year.

Within the member states companies are required to implement energy efficiency measures to achieve the national target values. Non-compliance results in fines for member states and companies.

Legal Obligations

Binding definition of national energy efficiency goals until 2020

3% refurbishment rate for public buildings

At least 1,5% energy savings per year – supported by fines in the case of non-compliance

Mandatory energy audits in large companies

EED Goals

Reduction of energy costs by lowering energy consumption

Improving the energy supply security by diversifying the energy imports

Stimulating economic growth

Climate protection by consumption reduction and implementation of energy efficiency measures

Find out about our main

Cities and Municipalities


Real estate owners and managers

AEC (Architecture Engineering and Construction)

Here are some of the

Accurate Energy Efficiency Optimization

Semergy involves elaborate calculations to determine the heating (energy) demands and other optimisation key figures. These calculations depend on multiple factors including (among others) the building geometry, building type, construction selection and building products. Since doing these calculations manually is a complex task, a Semergy user can benefit from the automated calculation and its accurate results.

Extensive Knowledge Repository

A Semergy user can benefit from the extensive data repository used by Semergy including different building constructions (walls, roofs, windows, etc.) as well as a multitude of suitable building products organized into classes (insulation materials, etc.). Each entry is supplemented with specific physical, environmental and economic properties for its evaluation during the optimisation run.

Interactive Decision Support

Since there is a multitude of potential building refurbishment measure combinations, Semergy includes an optimisation and decision support methodology that supports the user in finding the optimal choice based on the user’s requirements, as well as economic and ecologic parameters, while still respecting the physical structure of the existing building.

Comprehensive Reporting

Since the finally selected optimisation solution’s properties might be difficult to remember in detail, Semergy provides the user with the option of creating a detailed written report than contains all details of the proposed optimisation solution, including the status quo building properties, the refurbishment measure details and the expected improvements in energy efficiency.
Have a first look at the
User interface
Web-based and intuitive user interface
Semergy is implemented as a Web application with an easy to use interface. The only requirements are access to the Internet and an installed Web browser. The Semergy project data is stored in a central database. Therefore,  users can access their projects from different machines including mobile devices without the need for locally storing project information. Semergy also keeps an archive of all user projects that allows users to reopen them as the basis for new projects.
Optimisation of energy demand
Semergy enables the optimisation of the energy demand of individual buildings by carefully choosing suitable refurbishment options. This includes, e.g., the thermal refurbishment of the building envelope and the replacement/modernization of the installed heating system. Any thermal refurbishment option influences the building envelope and, thus, the overall heating demand due to the improvements of the building construction’s u-value. Furthermore, the modelling of the heating system allows calculating the overall heating energy demand as well as the primary energy demand with respect to the heating energy carrier in use. The replacement of the installed heating system (modernization or switch to a more eco-friendly and efficient energy carrier) improves the end energy and thus the building’s final primary energy demand.
Extended cost-benefit analysis
The selection of the optimal refurbishment option depends on multiple factors. Therefore, Semergy identifies each refurbishment package in three categories: energy efficiency, costs, and sustainability. Energy efficiency is determined by the building’s heating demand, heating energy demand and primary energy demand. Each individual refurbishment option influences these values. Costs are determined in both investment and running costs (i.e. energy costs). This allows identifying the amortisation time when comparing the investment costs with the energy savings. And finally, sustainability is measured in delta OI3 numbers that factor in the global warming potential, acidification potential and non-renewable primary energy of each involved building product (e.g., insulation material).
Interactive decision support
The three optimisation targets energy efficiency, costs and sustainability are opposing: More energy efficient and sustainable refurbishment options are usually more costly and vice versa. The requirements of users are in general different. For example, some users focus on energy efficiency, whereas others focus on costs. Therefore, Semergy presents multiple solution packages as optimal trade-offs between the three optimisation targets instead of presenting a single solution with an aggregated optimisation target. Since there are a lot of potential combinations of refurbishment options (individual building products, construction types, etc.), the potential solution list is very large. Semergy’s optimisation algorithm filters out the unfeasible und less performing measure combination and presents the user the list of optimal trade-offs. The user is then presented with an interactive selection method that allows the user to compare the solutions with each other to support the user in making the final decision.
Custom floor plan
Semergy allows the user to specify their buildings either in a basic style where only the general floor geometry (square, L/T-form) and floor numbers are entered or in a more elaborate style where custom floor plans are possible. In the geometry definition phase of the latter type, the user can create custom floor plans using a simple drawing interface to determine the position of walls, doors and windows of different types. Based on these specifications, the Semergy logic automatically identifies the position and size of individual rooms, floors, and the whole building. With the option to determine the floor height and room functions, an accurate building model can be specified.
Building shadowing and heating systems
In addition to the custom floor plans, Semergy also implements support modules to specify input variables usually neglected in other end-user building optimization tools, the specification of building shadowing and installed heating systems. Shadowing that reduces the solar gains is modelled in both self and external shadowing forms: Self shadowing is modelled by specifying shading elements per each window, while external shadowing can be specified by drawing other buildings in close proximity in the drawing interface. For both cases, the Semergy’s geometry module creates a 3D representation of the building and identifies the shading factor based on the sun path and the visible sky from each window’s viewpoint. With the corresponding solar radiation calculation, the correct reduction of solar gains due to shadowing is determined by the system automatically.
3D Visualisation
The (elaborate) building geometry input method involves a top-down view to let the user draw the floor plans in a 2D environment. This was preferred over a 3D environment for the sake of simplicity and easier user input: Existing architectural plans are also represented as 2D images which makes it easier to be used as templates for the Semergy geometry model. Semergy’s geometry module is then responsible for converting the 2D into a 3D building model. Because each floor is drawn individually, it may be difficult to ensure that the model was drawn correctly. Therefore, Semergy presents the user a 3D-rendered version of the building to provide feedback on the user’s input. The 3D interface allows the (de)activation of individual building components to declutter the user’s view.
Support for the planning of new buildings
Semergy not only enables users to plan refurbishment projects, it also supports users when designing new building with respect to energy efficiency, building costs, and sustainability of building products. The initial geometry specification phase is similar to that of the refurbishment project type where the overall building geometry including additional properties like usage type and roof type is entered. Then the system identifies all necessary building construction types including walls, floors, roof and windows and preselects potential constructions and materials which are specifically designed for new buildings. Thus the user can be ensured that only state-of-the-art constructions are chosen. Finally, the system identifies the optional building options with respect to the optimisation parameters.
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