An airtightness test certificate remains valid as long as the building’s airtightness characteristics remain unchanged, though there is no universal expiry date for the certificate itself. However, the certification for testers, such as those from the Federation of European Heating and Airconditioning Associations, must be renewed every three years, contingent on the demonstration of continued competence. Ratio Seven Limited, based in Nantwich, Cheshire, provides comprehensive airtightness testing services, ensuring compliance with regulatory standards by employing qualified professionals. Established in 2008, the company collaborates with housebuilding firms on projects ranging from rural to large urban residential developments.

Energy-efficient lighting systems are pivotal in reducing global energy consumption and lowering greenhouse gas emissions, with innovative options like LED technology offering up to 90% energy savings over traditional incandescent bulbs. These systems provide multifaceted benefits, including reduced operating costs, lower carbon emissions, and extended lifespan, all while maintaining optimal light quality. Implementing these solutions through re-lamping, upgrading fixtures, and employing advanced lighting controls can significantly enhance energy efficiency in buildings. Ratio Seven Limited, a UK-based energy and building consultancy, leverages its industry expertise to facilitate the adoption of such efficient lighting systems, thereby supporting sustainable development across various projects.