One of the main elements of the free insulation grant meant to increase building energy efficiency is internal wall insulation, or IWI. By adding insulation materials to the inside surfaces of exterior walls, IWI efficiently creates a thermal barrier that reduces heat loss and enhances the structures’ overall energy efficiency. By controlling indoor temperature, this method might lessen the need for excessive heating and, as a result, cut energy consumption. Affordably and with support, qualifying households can install internal wall insulation with the ECO 4 insulation grant, improving living conditions and promoting environmental sustainability at the same time. By implementing IWI, the insulation program contributes to the creation of more energy by being in line with the larger objectives of energy conservation and carbon emission reduction.