Dwelling load calculator

Size the service for a single-family house. Enter what's in it, and switch methods to compare.

Method

Standard methodOptional method (220.82)

The house

Living area

ft²

Small-appliance circuits

Laundry circuits

Appliances that stay with the house

Water heater, dishwasher, disposal, built-in microwave and similar. The range, dryer, heat and A/C go below.

Cooking, drying, heating and cooling

Range

Dryer

Electric heat

Separately controlled heaters

A/C or heat pump

Largest motor

How this is calculated

Standard method: 3 VA/ft² general lighting (Table 220.12), 1500 VA per small-appliance and laundry circuit (220.52), demand from Table 220.42. Fixed appliances at 75% when there are four or more (220.53). Dryer at the larger of 5000 W or nameplate (220.54). One range from Table 220.55. The larger of heating or A/C (220.60). Plus 25% of the largest motor.
Optional method (220.82): all general loads at nameplate, the first 10 kVA at 100% and the rest at 40%, then the largest heating or A/C option from 220.82(C).
Heat-pump supplemental heat and thermal-storage options under 220.82(C) aren't modeled yet.
Service size is the next standard rating from 240.6(A), never below 100 A (230.79(C)). Size the service conductors with 310.12.