Service Size Load Calculation
The standard NEC 220.82 calculation for a one-family dwelling: general load, small-appliance circuits, the appliance demand factors, and the amps your main lands on.
Heat and A/C are counted at the larger one plus 25%, not both. An EV charger is 125% of its continuous draw, so a 48 A charger is 12,000 VA at the panel.
How the math works
- General load (220.82(A)): 3,000 VA for the first 35 sq ft plus 3 VA per sq ft for the remainder. A 2,000 sq ft house = 3,000 + 1,965 × 3 = 8,895 VA.
- Small-appliance and laundry (220.82(B)): 1,500 VA for each 20 A small-appliance circuit (kitchen, dining, pantry, living) and each laundry circuit, added at full value, not derated.
- Appliances (220.82(C)): range at the Table demand (8,000 VA for a 12 kW range), clothes dryer at 5,000 VA, water heating at nameplate, and the larger of space heat or A/C plus 25% of it. The sum of these is taken at 100% of the first 10,000 VA and 40% of the remainder.
- Continuous loads: an EV charger at 48 A is 125% × 38.4 A × 240 V = 11,520 VA at the panel; the largest motor adds 25% of its rating; a well pump and a hot tub are nameplate at 100%.
- Service size: net VA ÷ 240 = the calculated load, and the main is the next standard size (100, 125, 150, 175, 200, 250, 300, 400). A 200 A service is the 2026 minimum for a house with an EV charger and heat, and the utility drop is sized to the main.
How many amps does a 2,000 sq ft house need?
The standard method on a 2,000 sq ft house with electric heat, a range, dryer, water heater, and 3 small-appliance circuits nets about 21,000 VA, which is 88 A: a 100 A service, and a 200 A panel for a 2026 house with an EV charger.
Do I need 200 amp service?
For a house with electric heat, central A/C, an electric range, and an EV charger, yes. The standard method lands near 120 to 150 A on a 2,500 sq ft all-electric house, and 200 A is the smallest main that leaves room for a hot tub, a shop, and a second charger.
Why is the general load 3 VA per square foot?
220.82(A): 3,000 VA covers the first 35 sq ft and 3 VA per sq ft beyond that models the lighting and small loads of the floor area, with no appliance in it. That is a general lighting load, not an appliance, so a finished basement counts.