How do I calculate electrical load for a residential panel?

Add general lighting at 3 VA per square foot, small appliance circuits at 1500 VA each, laundry at 1500 VA, and all large appliances. Apply NEC demand factors: first 3000 VA at 100%, remaining at 35%.

What is the NEC demand factor for residential loads?

NEC Table 220.42 specifies the general lighting demand factor: 100% for the first 3000 VA and 35% for the remainder from 3001 to 120,000 VA. This accounts for the fact that not all lights and outlets are used simultaneously.

How do I determine the right panel size for my home?

Calculate total demand load in VA, divide by 240V for single-phase residential service, and round up to the next standard panel size (100A, 200A, or 400A). Most modern homes need at least 200A service.

Electrical Load Calculator

Size residential panels per NEC Article 220. Enter square footage, appliance loads, and get minimum service amperage and recommended panel size.

Building Info

Square Footage

Small Appliance Circuits

Laundry Circuits

Large Appliances

Description	VA	Demand Factor	Demand VA

How to Calculate Residential Load

NEC Article 220 standard method for single-family dwellings.

Enter Building Info

Input square footage (3 VA/sqft), small appliance circuits (1500 VA each, minimum 2), and laundry circuits (1500 VA each).

Add Appliances

List all large appliances like range, dryer, water heater, AC, etc. Dryer minimum 5000W, range under 12kW = 8000W.

Apply Demand Factors

First 3000 VA at 100%, remainder at 35% per NEC Table 220.42. Result is minimum service amperage at 240V.

NEC Article 220 Summary

Key demand factors for residential load calculations.

Load Type	Unit Value	Demand Factor
General Lighting	3 VA per sq ft	First 3kVA 100%, rest 35%
Small Appliance Circuits	1,500 VA each (min 2)	Included in general lighting
Laundry Circuit	1,500 VA	Included in general lighting
Electric Range (<12kW)	8,000 VA	100%
Electric Dryer	5,000 VA (min)	100%
Water Heater	Nameplate rating	100%
HVAC Equipment	Nameplate rating	100%

Frequently Asked Questions

Common questions about residential load calculations.

Multiply square footage by 3 VA for general lighting. Add 1500 VA per small appliance circuit and 1500 VA for laundry. Add all large appliances. Apply NEC demand factors and divide by 240V for minimum service amperage.

NEC Table 220.42 specifies: 100% for the first 3000 VA of general lighting load, and 35% for the remaining general lighting load from 3001 to 120,000 VA. Large appliances do not receive this demand factor.

A 2500 sq ft home typically requires at minimum 200A service. The general lighting load alone is 7500 VA (2500x3). After applying demand factors and adding appliances, 200A is the standard recommendation for modern homes.