prEN 12831-1

Energy performance of buildings - Method for calculation of the design heat load - Part 1: Space heating load, Module M3-3

This European Standard covers methods for the calculation of the design heat load for single rooms, building entities and buildings, where the design heat load is defined as the heat supply (power) needed to maintain the required internal design temperature under design external conditions.
Table 1 shows the relative position of this standard within the set of EPB standards in the context of the modular structure as set out in EN ISO 52000 -1.
NOTE 1   In CEN ISO/TR 52000 2 the same table can be found, with, for each module, the numbers of the relevant EPB standards and accompanying technical reports that are published or in preparation.
NOTE 2   The modules represent EPB standards, although one EPB standard may cover more than one module and one module may be covered by more than one EPB standard, for instance a simplified and a detailed method respectively. See also Clause 2 and Tables A.1 and B.1.
(...)

Energetische Bewertung von Gebäuden - Verfahren zur Berechnung der Norm-Heizlast - Teil 1: Raumheizlast, Modul M3-3

Performance énergétique des bâtiments - Méthode de calcul de la charge thermique nominale - Partie 1 : Charge de chauffage des locaux, module M3-3

Energijske lastnosti stavb - Metoda za izračun projektnih toplotnih obremenitev - 1. del: Toplotne obremenitve prostora - Modul M3-3

General Information

• Status: Not Published
• Publication Date: 08-May-2025
• ICS: 91.140.10 - Central heating systems
• Technical Committee: CEN/TC 228 - Heating systems in buildings
• Drafting Committee: CEN/TC 228/WG 4 - Calculation methods and system performance and evaluation
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 17-Apr-2025
• Due Date: 21-Dec-2023
• Completion Date: 17-Apr-2025
• Directive: 2010/31/EU - Directive 2010/31/eu of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings (recast)
• Mandate: M/480 - Mandate to CEN, CENELEC and ETSI for the elaboration and adoption of standards for a methodology calculating the integrated energy performance of buildings and promoting the energy efficiency of buildings, in accordance with the terms set in the recast of the Directive on the energy performance buildings (2010/31/EU)
• Ref Project: oSIST prEN 12831-1:2025 - Energy performance of buildings - Method for calculation of the design heat load - Part 1: Space heating load, Module M3-3

Relations

• Revises: EN 12831-1:2017 - Energy performance of buildings - Method for calculation of the design heat load - Part 1: Space heating load, Module M3-3
• Effective Date: 28-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2025
Energijske lastnosti stavb - Metoda za izračun projektnih toplotnih obremenitev -
1. del: Toplotne obremenitve prostora - Modul M3-3
Energy performance of buildings - Method for calculation of the design heat load - Part 1:
Space heating load, Module M3-3
Energetische Bewertung von Gebäuden - Verfahren zur Berechnung der Norm-Heizlast -
Teil 1: Raumheizlast, Modul M3-3
Performance énergétique des bâtiments - Méthode de calcul de la charge thermique
nominale - Partie 1 : Charge de chauffage des locaux, module M3-3
Ta slovenski standard je istoveten z: prEN 12831-1
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2025
ICS 91.140.10 Will supersede EN 12831-1:2017
English Version
Energy performance of buildings - Method for calculation
of the design heat load - Part 1: Space heating load, Module
M3-3
Performance énergétique des bâtiments - Méthode de Energetische Bewertung von Gebäuden - Verfahren zur
calcul de la charge thermique nominale - Partie 1 : Berechnung der Norm-Heizlast - Teil 1: Raumheizlast,
Charge de chauffage des locaux, module M3-3 Modul M3-3
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 228.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12831-1:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 5
Introduction . 6
1 Scope . 8
2 Normative references . 12
3 Terms and definitions . 12
4 Symbols and abbreviations . 16
4.1 Symbols . 16
4.2 Subscripts . 17
5 Description of the methods . 19
6 Standard method – Heat load of rooms, building entities and buildings . 20
6.1 Output data . 20
6.2 Input data . 21
6.3 Calculation procedure . 28
6.3.1 Design heat load . 28
6.3.2 Design transmission heat losses of a heated space (i) . 29
6.3.3 Design ventilation heat loss . 33
6.3.4 Additional heating-up power in intermittently heated spaces . 42
6.3.5 Time constant . 43
6.3.6 Heat transfer coefficients without temperature adjustment . 44
6.3.7 External design temperature (climatic data) . 45
6.3.8 Influence of the heat emission system in high rooms (ceiling height ≥ 4 m) . 47
7 Simplified method for the calculation of the design heat load of a heated space (single
rooms) . 49
7.1 Output data . 49
7.2 Input data . 49
7.3 Calculation procedure . 50
7.3.1 Design heat load of a heated space . 50
7.3.2 Design transmission heat loss of a heated space . 51
7.3.3 Design ventilation heat loss of a heated space . 51
8 Simplified method for the calculation of the building design heat load . 52
8.1 Output data . 52
8.2 Input data . 52
8.3 Calculation procedure . 53
8.3.1 Building design heat load . 53
8.3.2 Building design transmission heat loss . 53
8.3.3 Design ventilation heat loss of a building . 54
9 Compliance check . 54
9.1 General . 54
9.2 Dimensioning of heat emission systems . 55
9.3 Dimensioning of heat generators . 55
Annex A (normative) Input data, structure for default values . 56
A.1 General . 56
A.2 Input data for the standard method (6) . 56
A.2.1 Consideration of thermal bridges . 56
A.2.2 Correction of U-values for the influence of building element properties and
meteorological conditions . 56
A.2.3 Heat loss through the ground . 56
A.2.4 Temperature adjustment for heat loss to by-design unheated spaces . 57
A.2.5 Internal temperatures of adjacent building entities . 57
A.2.6 Influence of the heat emission system in high rooms . 57
A.2.7 Volume-specific thermal storage capacity c . 58
eff
A.2.8 Specific properties of air. 58
A.2.9 Volume flow ratio between room (i) and zone (z) . 58
A.2.10 Air tightness . 58
A.2.11 Minimum air change rate . 59
A.2.12 Coefficient for the volume flow ratio f . 59
qv,z
A.2.13 Estimation of design data of external ATDs . 60
A.2.14 Pressure exponent for leakages . 60
A.2.15 Adjustment factor for the orientation of the zone (orientation factor) . 60
A.2.16 Adjustment factor for the number of exposed facades . 60
A.2.17 Air volume flow through large openings . 60
A.2.18 Additional heating-up power in intermittently heated spaces φ . 61
hu
A.2.19 Heat gains Φ . 61
gain
A.3 Input data for the simplified methods (7, 8) . 61
A.3.1 Ratio between external and internal surface areas . 61
A.3.2 Thermal bridges . 61
A.3.3 Temperature adjustment factor f . 61
x
A.3.4 Air change rate . 62
A.4 Input data for the standard method and the simplified methods . 62
A.4.1 Climatic data . 62
A.4.2 Internal design temperature . 64
A.4.3 Simplified determination of U-Values . 64
Annex B (informative) Input data, default values . 65
B.1 General . 65
B.2 Input data for the standard method (6) . 65
B.2.1 Consideration of thermal bridges .
...