Since 2011, when the welsh government first established nest, over 98,000 households in wales have benefited from free advice and support, with over 29,000 of those households receiving a package of free home energy efficiency improvements.â. Uk plumbing company snapped up by aussies for nearly £690m. Retrofits are fuel-specific, so see the following sections for retrofit information. Why not pick up the phone and talk to our friendly.