nZEB estimation method of the Living EPC Tool

Written by REGEA

The Living EPC Tool is a complex interactive web-based application consisting of data from collected energy performance certificates and accompanying reports, updated with technical and financial parameters describing current status of each building. As a result, the tool offers different combinations of energy efficiency and renewable measures for reaching nZEB requirements.

Since the tool should be a very simple to use- a significant number of assumptions had been used in order to simplify it. These simplifications made an input process significantly easier, while influencing the results’ accuracy to some extent.

After the input data is entered- the tool runs the nZEB estimation process through a range of formulas while targeting the country specific values for: percentage of renewable energy used on-site, building envelope thermal transmittance values (U-values), primary energy, specific energy for heating.

Estimation process, which is happening in the tool background, can be presented through four phases. 
In first phase, by analyzing the current percentage of renewable energy used on-site- the tool estimation formula can replace existing HVAC systems with those which are using renewable energy in order to generate power. In second phase, the tool estimation formula is programmed to 'build' a required U-value (by adding the thermal insulation on the building envelope) after which the condition of primary energy is checked (third phase). If primary energy, after achieving a required U-values for building envelope, is not in accordance with specific country target- the tool will display the message that 'nZEB standard cannot be estimated'. If primary energy condition is in accordance with specific country target- then the tool is checking the condition for specific energy for heating (fourth phase).

If all four conditions are met, in accordance with country specific targets, the tool will display a list of possible combinations (EE&RES measures) whose implementation could result with the nZEB buidling.