Dwelling load.
Run the standard dwelling method without losing the order. Start with 3 VA per square foot, add the required small-appliance and laundry circuits, apply the demand factor, then add the range, dryer, water heater, larger of heat or AC, and any EVSE load.
Uses NEC Article 220 dwelling-load steps, Table 220.55 range demand, the 5,000 VA dryer minimum, the heat-versus-AC rule, and the 310.12 dwelling service-conductor allowance.
Dwelling load is bookkeeping before it is math. Pick the method, keep the buckets separate, and do not add heat and AC together. Most wrong answers come from one load counted in the wrong step. If you searched for residential electrical load calculator, this is the Article 220 dwelling-service version.
2,400 sq ft dwelling with range, dryer, heat, and 5 ton AC
Inputs
- 2,400 sq ft dwelling
- Two small-appliance circuits and one laundry circuit
- 12 kW range and 5 kW dryer
- 15 kW electric heat
- 5 ton AC at the calculator convention of 3,600 VA per ton
Result
General-load demand is 6,045 VA. Range demand is 8,000 VA. Dryer is 5,000 VA. AC is larger than heat at 18,000 VA. Total demand is 37,045 VA, or 154.35 A at 240 V. That rounds to a 200 A service, with 166 A service-conductor ampacity under the 83% dwelling allowance.
Here is the trap: the 83% rule applies after you pick the dwelling service rating. Do not multiply the calculated load by 83% and use that smaller number to pick the service.
The dwelling-load mistakes that cost exam points
- Adding heat and AC together. Take the larger one. Drop the smaller one. They are not both in the same dwelling demand total.
- Using the range nameplate directly. A common 12 kW household range does not add 12 kW of demand in the standard method. Read Table 220.55.
- Forgetting the required circuits. Two small-appliance circuits and one laundry circuit add 4,500 VA before the demand factor.
- Misusing the 83% rule. Pick the service rating from the calculated service current, then apply the dwelling conductor allowance to that selected rating.
After you run the calculator, drill the setup
Dwelling load calculator questions
How do you calculate a dwelling load?
For the standard method, start with 3 VA per square foot, add the required small-appliance and laundry circuits, apply the Article 220 demand factor, then add range, dryer, water heater, the larger of heat or AC, and any EVSE load.
Do you add heat and air conditioning together?
No. Heat and air conditioning are noncoincident loads for a dwelling. Use the larger value and drop the smaller one. Adding both is one of the fastest ways to miss a dwelling-load question.
What is the dryer minimum in a dwelling load calculation?
If an electric dryer is present, use the larger of the nameplate value or 5,000 VA. If the question gives a smaller dryer nameplate, the 5,000 VA minimum still controls.
Does EV charging count as continuous load?
Yes. EVSE is treated as a continuous load, so the calculator applies the 125% multiplier to the charging current before adding it to the dwelling load.
Which NEC article covers dwelling load calculations?
Dwelling load calculations live in NEC Article 220. Range demand uses Table 220.55, dryer load uses the dryer rule in Article 220, heat vs AC is the noncoincident-load step, and qualifying dwelling service conductors use 310.12.
Is this the same as an electrical load calculator?
This page is the dwelling version of an electrical load calculator. It is built for residential service-load exam problems, not a full commercial load study. If you searched for residential electrical load calculator, this is the right tool.
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