Without standards, architects and builders are under pressure to minimise investments in efficiency to hold down the initial cost of the buildings, even when the additional investments would be repaid rapidly through lower energy costs. These standards now have the additional advantage of reducing GHG emissions from the burning of fossil fuels. Building energy codes have become widespread. Many countries modelled their building codes on those in other countries. While most codes are adopted nationally, local agencies often are responsible for their enforcement.
Buildings differ in size, function, and location.
An effective enforcement system requires trained local inspectors, who periodically visit the construction sites of complex buildings. Studies in the United States report rates of non-compliance of 50 per cent or more. After building standards laws are approved, it is necessary to have strong implementation, training, and enforcement programmes to realise their potential benefits. Some governments have also moved lately to mandate appliance and equipment energy efficiency standards. The United States and Canada cover the most appliances, followed by Switzerland and China.