The assessment concludes with a certificate detailing the energy efficiency and environmental CO2 impact of your home. This is similar to the A-G rating scheme that is required on household appliances such as fridges. The most important element is the inspection visit, lasting approximately 1-hr in the case of a 4-bedroom house. The inspection will consider the built construction of the home, the sources of heating and hot water provision, together with an assessment of the prevention of heat loss through the wall, roof, doors, windows and floor. The resulting certificate will also include, where relevant, suggestions for energy-saving improvements. The suggestions for improvement range from improving the insulation on hot water tanks, to installing solar water heating.