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As sustainable and resilient design becomes an industry priority, Norway has introduced stricter building regulations to meet carbon-neutral initiatives by 2027. These building regulations, also known as TEK17, help manage future building projects in Norway and establish mandatory requirements around end energy. Software applications like FenestraPro are used to conduct energy model analysis, check code compliance, and identify sustainable solutions that can be applied to a new building.  

This blog will explain what TEK17 is and how thermal performance, daylighting and solar heat gains can be measured and managed to ensure projects meet regulations early in the design process. 

What is TEK17? 

TEK17 is a set of Technical Building Works Regulations created to regulate energy-efficiency levels for finished buildings. It requires designers to establish and calculate end energy use to manage a building’s total net energy consumption and for elements’ minimum U-values.

According to TEK17, the general energy-efficiency requirements are set according to the following principles:  

  • Buildings will be designed and constructed in a way that satisfactory energy performance is facilitated;  
  • The energy requirements apply to the building’s heated gross internal area (BRA);  
  • U-values are calculated as the mean for the various elements of the building.  

TEK17 requires detailed energy calculations of entire design projects to demonstrate compliance. Designers need to consider energy modelling and thermal performance analysis in the earliest stages of the design process to minimize the risk of late-stage redesign. Specifically, thermal performance, daylighting, and solar heat gains must be considered to ensure that the building does not overheat.  

Below we will demonstrate different workflows for measuring thermal performance, daylighting, and solar heat. 

Measuring Thermal Performance, Daylighting and Solar Heat Gains

Measuring Thermal Performance 

TEK17 provides prescriptive guidance to demonstrate compliance, including energy-saving measures such as thermal performance standards for building elements in different building categories (Section 14-2 (2), 14-3 & 14-5). In some cases, these include limitations on the proportion of windows and doors that can be used. FenestraPro facilitates compliance checking for thermal performance requirements and intuitively establishes the maximum percentage of glazing from the earliest stages in the design. 

Image 1 below shows a conceptual model with the required standards for TEK17. FenestraPro highlights the values that are non-compliant in red.  

Image 1

Image 2 highlights where thermal performance values are not specified in the detailed model. Designers can adjust the analytical properties for the element and display when thermal performance values are not compliant with the selected standard or code. 

Image 2

Managing Natural Daylight

Under TEK17 Section 13-7, daylight requirements are fulfilled by ensuring that the average daylight factor in the room is at least 2.0%. FenestraPro provides daylight factor values in real-time that enable compliance checking based on a 2% minimal design daylight factor. It considers the area of glazing, impact of shading devices, surrounding buildings and self-shading, and the glazing specification with appropriate Visible Light Transmittance (VLT).  

Image 3

Images 2 and 3 above shows how FenestraPro provides real-time daylight factors for facades separated into various surfaces based on internal zoned spaces or rooms. Although the average daylight factor for all façades is 5.12%, individual surfaces may be below the minimum required 2% or above the maximum recommended 5%. In this example, designers may consider a higher performance glass type (with lower SHGC) to reduce heat gain, adding fritting patterns to the glass, or using shading devices to reduce discomfort from excessive daylight and glare.

Considering Solar Heat Gain 

Consideration must be given to passive solar heat gain to reduce the heating and cooling loads that account for over a quarter of a building’s energy use. FenestraPro provides a balanced understanding of thermal performance (heat loss), daylighting, and solar heat gain.   

Image 4 below shows an overheated, highly glazed south-facing façade approaching the 25W/m2 maximum recommendation. In this instance, the amount of glazing could be reduced, perhaps with an increase in the amount of spandrel.

Image 4

Alternatively, changing the glazing specification to a glass with a lower solar heat gain coefficient (SHGC) or shading could be used to reduce the heat gain. However, when introducing shading devices, consideration should also be given to the impact of daylight.


Norway has introduced building regulations for zero-carbon design by 2027. TEK17 provides designers with strict requirements and guided resources to calculate end energy in the earlier stages of design. FenestraPro can assist in calculating thermal performances, daylighting, and solar heat gains in real-time to provide accurate calculations before building works begin. 

To test our Energy Model Analysis Tool and Compliance Checker on one of your projects, register for a personalized demo here.   

Megan Doyle

Marketing Manager @FenestraPro. Passionate about SEO, saving our oceans, and architectural history.