Residential load is a term which is used to describe the amount of electricity entering a residence at any given time. The amount of electricity a residence can access is typically limited by the amount of its service drop. When homes are constructed or electrical systems are renovated, an electrician must perform a number of calculations to estimate maximum residential load to determine how the system should be laid out, with the goal of preventing electrical problems caused by overloading the system.
In some regions of the world, utilities have promoted load management programs which are designed to compensate for aging electricity grids by managing the use of power at peak times. These programs also generate savings for utility customers, helping them spend less on electricity. Load management programs control high-load electrical devices like water heaters and fridges, deferring electricity use during peak periods to free up power resources. For example, a water heater might automatically click on when the thermostat determines that the water inside is starting to cool, but under a load management system, the heater would stay off, clicking on later when the demand for electricity across the grid is not so high.
Residential load calculations determine the amount of service drop appropriate to a residence, the type of wiring which should be used, and how circuits should be arranged. Electricians also perform calculations to determine the heating and cooling needs of a structure so that the best system can be installed. A system which is too small will not be sufficient, while a system which is too large will be inefficient. Installing the right system will cut energy costs and keep the temperature more comfortable.
Utilities base billing on residential load. Houses which use more than the average will be billed more, reflecting the increased burden they place on the grid, while houses which use less power will be rewarded with lower rates. This system is designed to promote energy efficiency, and to keep the grid operable. Electricity bills usually break down energy usage for their customers, and may include measurements of peak residential load so that people can see when they were using the most energy.
Many nations have faced increasing demands on their electrical grids as the result of ballooning populations. Retrofitting and replacing grids is costly and time consuming, and can cause interruptions in electrical service. As a result, some grids have been allowed to reach a woeful state, which means that problems with electricity allocation will only increase in the future.