The obligated energy suppliers do the job with installers to introduce certain efficiency measures into your residences, such as loft, floor or wall insulation, or heating measures. - Condenser Boiler - a condensing boiler could have a white or black plastic pipe under the boiler heading outside the house) NREL https://freeecogrants.co.uk/what-are-the-benefits-of-applying-for-external-wall-insulation-grants/