A copy brings over square footage, appliances, cooking, dryer, EV, motor and HVAC loads. The unit count is never copied.
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Dwelling Unit Load Calculator
NEC 220 — Standard Method (Part III) vs. Optional Method (220.82), Compared
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Project Info
Dwelling & Circuit Inputs
Common to both methods — general lighting, small appliance, and laundry loads per 220.41 / 220.52
120/240 V, or 120/208 V from a 208Y system. One setting for the building — also shown under Multifamily Feeder Inputs.
Also editable from the Unit Mix table on the Feeder tab — both stay in sync.
1500 VA per circuit — 220.52(A)
1500 VA per circuit — 220.52(B). Set to 0 only where a common laundry facility is provided elsewhere on the premises for all occupants — 210.52(F) Exception No. 1.
Enter each cooking appliance separately. Standard method (Table 220.55): appliances over 8¾ kW through 27 kW use Column C (each under 12 kW counted as 12 kW; +5% per kW or major fraction the average exceeds 12 kW — Notes 1 & 2). Appliances over 1¾ kW through 8¾ kW use Column A (under 3½ kW) or Column B (3½–8¾ kW) per Note 3, or Column C with the rest — whichever is lower. Appliances 1¾ kW or less, or over 27 kW, are outside the table and taken at 100%. Optional method: full nameplate kW sum, no table reduction — 220.82(B)(3).
Standard method: each dryer at the greater of nameplate or 5000 W, 100% demand — 220.54 / Table 220.54. Optional method and 220.84 feeder: nameplate rating — 220.82(B)(3), 220.84(C)(3). (Table 220.54's demand-factor reduction below 100% applies to the count of dwelling-unit dryers on a multi-unit feeder, not to multiple dryers within a single unit.)
Fixed / Fastened-in-Place Appliances
Water heater, dishwasher, disposal, microwave, compactor, etc. — 220.53
Standard method: if 4 or more fastened-in-place appliances rated ¼ hp / 500 W or greater (excluding cooking equipment, dryers, space heating, A/C, and EVSE), apply a 75% demand factor to those appliances' sum — 220.53. Appliances entered below 500 VA don't count toward the four and are carried at 100%. Optional method: all appliance nameplates included in the general 100%/40% demand block — 220.82(B)(4).
EV Charging Equipment
220.57 (standard) & 220.82(B) (optional — full nameplate, no 7200 VA floor)
Standard method: greater of 7200 VA or nameplate rating per unit, 100% demand, calculated separately from the fixed-appliance load — 220.57. Optional method: actual nameplate VA (the 7200 VA floor doesn't apply to the optional method) folded into the general 100%/40% block — 220.82(B). Not evaluated here: an EVEMS (Article 750) load-management system that could reduce this further.
Motor Loads
Well pump, sump pump, other dwelling-unit motors — 430.24
Sum of nameplate VA plus 25% of the largest single motor's nameplate VA — mirrors 430.24's rule for feeder/branch-circuit conductors supplying two or more motors. Standard method: added as its own line at 100% demand. Optional method: the same value is folded into the 220.82(B) general load, so it's subject to the 100%/40% demand factor.
Heating & Air Conditioning
220.60 (standard, noncoincident) & 220.82(C) (optional, largest applicable category)
Electric heating (resistance or heat pump) is subject to Article 220's heating demand factors (220.60 standard, 220.82(C) optional). A gas/oil/propane furnace has no electrical heating load to demand-factor — only its blower motor/controls draw current, so it's treated as a fixed connected load instead.
Small electric heating units installed in addition to the gas/oil/propane furnace (bathroom heaters, etc.) are still "electric space-heating equipment" under Article 220 — they get demand-factored and compared against A/C below, separately from the furnace's own blower/controls load above.
Standard method always uses 100% of the larger of heating or cooling (noncoincident loads, 220.60). Optional method uses 100% of A/C vs. the selected category's demand on the heating VA, and takes the larger of the two.
220.82(C)(3): the compressor is taken at 100% and only the remaining supplemental electric heat at 65%. Enter the compressor's nameplate VA; the electric heating load entered above (space heating, or supplemental electric heating with a gas furnace) stays the total — compressor + supplemental — which the standard method uses at 100%. Not evaluated: the (C)(3) allowance to omit the compressor where it's interlocked so it can't run with the supplemental heat — this tool always adds it (conservative).
Optional Method Eligibility
220.82 applies only to a dwelling served by a single 100A+ service/feeder supplying that one dwelling unit
Results — Method Comparison
Both totals divided by service voltage for calculated load current
Standard Method
NEC 220 Part III
Total calculated load
— VA
Load current: —
Optional Method
NEC 220.82 — one-family dwelling
Total calculated load
— VA
Load current: —
—
Uncheck for a single-family or single-unit project with no shared feeder. The 220.84 calculation below is then marked not applicable, and the Drawing PDF export then has only the dwelling-unit page — the feeder page is left out.
Multifamily Feeder Inputs
220.84 — optional calculation, three or more dwelling units on one feeder or service
Each unit type's appliance, cooking, dryer, EV, motor, and HVAC package is edited on its own tab. Feeder voltage applies to the whole building (currently 240 V) and is the same setting as the Dwelling Unit tab's service voltage.
Three-phase: A = VA ÷ (V × √3). Single-phase: A = VA ÷ V.
Unit Mix
Composition of dwelling units on this feeder — up to 12 unit types
Each unit type's square footage, appliances, and HVAC are set on its own tab (created automatically when you add a type here). Total dwelling area and total unit count for Table 220.84 are computed automatically from this mix.
220.84 Eligibility
Three or more units plus all three 220.84(A) conditions must hold, across every unit type, to apply Table 220.84
Auto-detected per unit type — checked when each type's cooking-appliance package has a combined nameplate rating > 0 kW. If any type has none, the 220.84(A)(2) Exception is applied automatically: the feeder load is the lesser of the Part III standard calculation and the Table 220.84 calculation with 8 kW of cooking added per unit lacking it.
Auto-detected per unit type — checked when each type's heating fuel is Electric, or its A/C load is greater than 0 VA.
Not one of the four 220.84(A) conditions above — NEC 220.85 (Two Dwelling Units) separately permits a 2-unit feeder to use the lesser of the Table 220.84 three-unit calculation and the standard Part III two-unit calculation. Enter 3 as this unit type's count on the Feeder tab to actually apply Table 220.84; checking this box only adds a note to the calculation output documenting that basis — it does not change any calculated value.
House / Common-Area Loads
Not part of the individual dwelling units — calculated per Part III and added at 100%, outside the Table 220.84 factor
E.g. corridor/stairway lighting, parking lot lighting, common laundry, elevators, pool/clubhouse, fire pump/sprinkler controls.
Results — 220.84 Feeder/Service Load
Connected load (per unit type × that type's count, plus aggregate lighting) × Table 220.84 factor, plus house loads at 100%