Approval Definitions

HETAS Product Approval Definitions

“The Appliance”

Means the named fully assembled end product, manufactured for the purposes of heating dwellings, and for which HETAS approval is sought.


HETAS Ltd, the certification body competent to issue a certificate of conformity and approve an appliance. HETAS operates the Heating Equipment Testing and Approval Scheme.

“The Manufacturer”

Means the person, partnership, company or sole distributor on whose behalf a signature appears on either the Form 4A or Form 5A.

“The Initial Type Test Report”

Means the test report submitted by the manufacturer to HETAS following initial type tests undertaken to an EN or BS standard by a Notified Test Laboratory and which is assessed by HETAS under clause 8 of these conditions.

“Notified Laboratory”

 A third party test laboratory accepted and listed by the European Commisision as being independant and technically competent to undertake the tests on those solid fuel fired appliances for which they have been notified as published in the Official Journal of the European Communities.

“Approved Appliance”

Means the appliance which has ben assessed by HETAS and gained approval and which is available for public purchase in the UK.

“SAP Efficiency”

This is the best available estimate of annual average efficiency when installed in typical domestic conditions in the UK, and it is used in SAP 2009 (the government’s methodology for calculating the energy performance of dwellings). For boilers which have been tested for full-load efficiency and part-load efficiency and the results accepted for the database, the SAP 2009 annual efficiency will be SEDBUK(2009). For older boilers, where test data is not available, the SAP 2009 annual efficiency is a default value based on type, age, and fuel.


SEDBUK stands for the Seasonal Efficiency of Domestic Boilers in the UK. This is an estimate of the seasonal efficiency of a boiler installed in typical domestic conditions in the UK, and is used in SAP assessments and the building regulations. It is an annual average, calculated from full-load efficiency and part-load efficiency test results and other data.


The organisation responsible for the operation of the MCS scheme.


Stands for the Microgeneration Certification Scheme and is the scheme operated by GEMSERV, for the independent certification of microgeneration products and services in accordance with consistent standards.