In particular within Europe, more and more countries are working on the concrete implementation of the set of EPB standards for the assessment of the energy performance of buildings.

The EPB standards offer specific choices to tailor the methodology to the national or regional situation. This was the subject of the second webinar. One of the key decisions in this process is whether or not to implement a calculation method with hourly calculation intervals instead of monthly. The set of EPB standards facilitates both choices.

The intention of this webinar was to show the main possibilities and limitations of both approaches, as described in the EPB standards.

Following the successful previous webinars:

this 4th webinar introduced and demonstrated the main possibilities and limitations of the monthly versus the hourly calculation method.

Some issues discussed during this webinar:

  • Is it easier to describe and calculate dynamic effects and interactions in low energy buildings with the hourly or the monthly method?
  • Is it easier to describe and calculate the operation of technical systems with the hourly or the monthly method?
  • Is it true that the hourly method inevitably requires more input data from the user than the monthly method?


In the past decades, the monthly method was quite satisfactory due to the high thermal losses and significant heat capacity of buildings. In the last years, the thermal insulation of new building envelopes has been greatly improved and this dramatically reduced the energy needs for heating. Deep renovation is encouraged and this means again an improved thermal envelope. Solar gains and internal heat gains play an increasingly important role, with strongly variations over the day and week.  Consequently, the traditionally simple monthly calculation method is challenged: how to take into account these dynamic effects in a realistic way and keep it simple? Or is an hourly calculation method a better alternative, without giving in on simplicity and transparency….


Download slide deck PDF

  • General introduction by Giulia LEGHISSA, Scientific communication at Eurac Research (BuildUp Editorial Board)


  • Introduction and overview of current EU practices by Jaap HOGELING, Chairperson CEN/TC 371, Energy Performance of Buildings project group, European Committee for Standardization (CEN)


  • Energy need and indoor temperatures calculation: hourly or monthly? by Dick VAN DIJK, EPB expert, EPB Center


  • Hourly or monthly? What about technical systems? by Laurent SOCAL, independent EPB expert


  • Moderated Q&A by Giulia LEGHISSA


Series of webinars on the EPB standards

This webinar series is jointly organized by BUILD UP and EPB Center’s experts under the scope of Service Contract ENER/C3/2017-437/SI2-785.185 “Support the dissemination and roll-out of the set of Energy Performance of Buildings standards developed under EC Mandate M/480” (duration September 2018 - September 2021).

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