Appendix A

Main and secondary heating systems

The main heating system is that which heats the largest proportion of dwelling. It is a heating system which is not usually based on individual room heaters (although it can be), and often provides hot water as well as space heating. Main heating systems are either identified via the Product Characteristics Database or are categorised on the basis of the generic types in Tables 4a and 4b.

A2.1 Identifying the main system

  1. If there is a central system that provides both space and water heating and

    it is capable of heating at least 30% of the dwelling, select that system as the main heating system. If there is no system that provides both space and water heating, then select the system that has the capability of heating the greatest part of the dwelling. For this purpose only habitable rooms should be considered (i.e. ignore heaters in non-habitable rooms).

  2. If there is still doubt about which system should be selected as the main system, select the system that supplies useful heat to the dwelling at lowest cost (obtained by dividing fuel cost by conversion efficiency).

epctk.appendix.appendix_a.apply_appendix_a()[source]

Todo

Move the main logic relating to appendix A from wherever it is now into this function!

A4 Description of the dwelling’s heating systems and software implementation

  1. If there is no heating system, assign electric heaters as the main system heating all rooms (no secondary system).

  2. If 25% or less of the habitable rooms are heated and their heating is by a room heater (not electric), assign electric heaters as the main system and the identified room heaters as the secondary system, applying the secondary fraction according to Table 11 for electric room heaters as the main system.

    If two main heating systems have been identified (e.g. a gas fire in one room, a coal fire in another room, plus 6 unheated habitable rooms) then:

    • assign electric heaters as main system1
    • assign the room heater entered as main system1 as the secondary system
    • main system2 remains as it is
    • set the fraction of heat from main system2 equal to heated habitable rooms divided by total habitable rooms

  3. Otherwise if there are any unheated habitable rooms and no secondary system has been identified, undertake the calculation with electric secondary heating

(portable electric heaters).
  1. If any fixed secondary heater has been identified, the calculation proceeds with the identified secondary heater, whether or not there are unheated habitable rooms.
  2. If there are no unheated habitable rooms and no fixed secondary heater in a habitable room, undertake the calculation with no secondary heating.
  3. An assumed heater, where main or secondary, is an electric portable heater. In case of main heating it does not have thermostatic control.

Table 11 gives the fraction of the heating that is assumed to be supplied by the secondary system. The treatment of secondary systems is not affected by any control options for the secondary system.

epctk.appendix.appendix_a.get_4a_main_system(dwelling, system_code, fuel, use_immersion_in_summer, hetas_approved)[source]

Get the main heating system according to Table 4a for the given dwelling

Parameters:
  • dwelling –
  • system_code –
  • fuel –
  • use_immersion_in_summer –
  • hetas_approved –
Returns:

heating system configured according to Table 4A
Return type:

HeatingSystem
epctk.appendix.appendix_a.get_4a_secondary_system(fuel, sap_type_code, electricity_tariff, use_immersion_heater_summer, hetas_approved)[source]

Get the secondary heating system according to Table 4a for the given dwelling

Parameters:
  • sap_type_code –
  • electricity_tariff –
  • use_immersion_heater_summer –
  • hetas_approved –
Returns:

Secondary heating system configured from Table 4a
Return type:

SecondarySystem
epctk.appendix.appendix_a.get_4b_main_system(dwelling, system_code, fuel, use_immersion_in_summer)[source]

Get the secondary heating system according to Table 4b for the given dwelling

Parameters:
  • dwelling (Dwelling) –
  • system_code –
  • fuel –
  • use_immersion_in_summer –
Returns:

Secondary heating system configured from Table 4b
Return type:

SecondarySystem
epctk.appendix.appendix_a.sap_table_heating_system(dwelling, system_code, fuel, use_immersion_in_summer, hetas_approved)[source]

Loads a HeatingSystem definition from SAP Table 4a if available, otherwise from Table 4b

Parameters:
  • dwelling –
  • system_code –
  • fuel –
  • use_immersion_in_summer –
  • hetas_approved –
Returns:

A heating system object with data loaded from the appropriate SAP table
Return type:

HeatingSystem