How Is Maximum Demand of Electricity Calculated?
Maximum demand is the highest amount of electrical power that a home, building, or facility is expected to use at one time. It is useful when estimating electrical loads, sizing equipment, and understanding the power requirements of a property.
How Is Maximum Demand Calculated?
A simple way to estimate maximum demand is:
Maximum Demand = Connected Load × Demand Factor
The connected load is the total rated power of all electrical appliances, lighting, and equipment connected to the electrical system.
The demand factor represents the proportion of the total connected load that is likely to be used at the same time.
Example
Suppose a house has a total connected load of 20 kW, and the estimated demand factor is 0.6:
Maximum Demand = 20 × 0.6 = 12 kW
So, the estimated maximum demand is 12 kW.
Why Doesn't Maximum Demand Equal Total Connected Load?
It is unlikely that every electrical appliance in a building will operate at full power simultaneously. For example, a home may have several air conditioners, heaters, ovens, and other appliances, but they are not necessarily all running at the same time.
This is why a demand factor is used to produce a more realistic estimate.
Maximum Demand vs. Connected Load
Connected load is the sum of the rated power of all connected equipment, while maximum demand is the highest expected power used at the same time.
For larger electrical installations, maximum demand calculations can involve different demand factors for lighting, heating, motors, appliances, and other loads. Local electrical codes and utility requirements may also specify how demand should be calculated.
Calculate Maximum Demand Quickly
If you already know the total connected load and an appropriate demand factor, you can calculate the estimated maximum demand in seconds.
Use our Maximum Demand Calculator to simplify the calculation and get a quick result without doing the formula manually.