5.1 Introduction This section gives guidance on specifying radiant heaters for space heating in new and existing buildings to meet relevant energy efficiency requirements in the Building Regulations. It includes guidance on measures, such as additional controls, that can be used to gain heating efficiency credits to improve the heat generator seasonal efficiency. 5.2 Scope of guidance The guidance in this section covers the types of radiant heater listed in Table 19. ****Table 19**** 5.3 Key terms Radiant heater seasonal efficiency (heat generator seasonal efficiency) is equivalent to thermal efficiency (net calorific value). For flued appliances, the manufacturer of the radiant heater should declare a thermal efficiency measured to the test standards BS EN 102026 or BS EN 1384227 as applicable. The calculation of the thermal efficiency (net calorific value) should: a. take account of the radiant heater and associated flue pipe/tailpipe within the building envelope b. exclude fans. 5.4 Radiant heaters Radiant heaters in new and existing buildings should have: a. an effective heat generator seasonal efficiency not worse than in Table 20 b. a controls package consisting of, as a minimum, time control and space temperature control with black bulb sensors. ****Table 20 Recommended minimum performance standards for radiant heaters**** 5.5 Heating efficiency credits for radiant heaters in existing buildings Heating efficiency credits can be gained by adopting the additional measures listed in Table 21. They are added to the heat generator seasonal efficiency (the thermal efficiency – net calorific value) to give the effective heat generator seasonal efficiency. ****Table 21 Heating efficiency credits for additional measures applicable to radiant heaters**** Example: Using heating efficiency credits to achieve the minimum effective heat generator seasonal efficiency for a radiant heater system A proposed building will have a flued non-luminous radiant heater system with a thermal efficiency (heat generator seasonal efficiency) of 84%. A black bulb sensor and an optimiser will be fitted. The heating efficiency credits associated with these measures are added to the appliance thermal efficiency to obtain the effective heat generator seasonal efficiency. Table 22 shows how credits are awarded for this example. ****Table 22 Example to illustrate the allocation of heating efficiency credits to a radiant**** Effective heat generator seasonal efficiencythermal efficiencyheating efficiency credits 84286% In this example, the application of additional measures to gain heating efficiency credits has brought the radiant heater’s effective heat generator seasonal efficiency up to the minimum recommended value.