Cavity and solid wall insulation systems must be covered by an appropriate lifetime guarantee to qualify for ECO (Energy Companies Obligation). In October 2014, Ofgem published a list of 13 guarantees which it considers meet the four criteria for appropriate guarantees.

The difficulties of finding affordable and appropriate guarantees for cavity and solid wall insulation have been key concerns of ECO Installers and Green Deal Providers. ECO funding is likely to be a pre-requisite for most cavity and solid wall insulation systems under the Green Deal due to the upfront costs required.

If an ECO installer uses a pre-approved guarantee, Ofgem will, when assessing the ECO measure notified by the energy supplier, accept that the guarantee is an appropriate guarantee.

ECO installers may still choose an alternative guarantee that meets the four requirements of financial assurance, duration, coverage and quality assurance. However, Ofgem would need to assess the appropriateness of the chosen guarantee when the ECO measure is notified. It is therefore likely that the Ofgem pre-approved list will be widely used by the Industry.