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Electrical Load Calculator
Calculate residential service load in volt-amperes and amps using a simplified NEC-style demand method.
General lighting load = 3 VA per square foot.
Common appliance checklist
Fixed appliance loads are included in the 10,000 VA / 40% demand calculation below. HVAC adds only the largest heating or cooling load, which keeps this close to a simple NEC residential load worksheet.
Recommended service size
100A
Demand load and amperage update live as you add appliances.
Adjusted demand load
0 VA
Connected load
0 VA
Amps @ 240V
0 A
Largest HVAC load
0 VA
General demand load
0 VA
NEC-style load breakdown
This uses a simplified dwelling-unit method: first 10,000 VA at 100%, remainder at 40%, plus the largest HVAC or heating load at 100%.
| Load component | Calculation | VA |
|---|
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Frequently asked questions
How is the general lighting load calculated?
This calculator multiplies your residence square footage by 3 volt-amperes per square foot, which is the common starting point for a dwelling-unit general lighting load.
Why is only the largest HVAC load counted?
In a simplified residential NEC load calculation, you generally add only the largest noncoincident heating or cooling load instead of stacking every possible HVAC load at once.
Does this replace a full code-compliant load calculation?
No. It is a planning tool for homeowners and contractors. Local code amendments, demand factors for fastened-in-place appliances, optional methods, and utility requirements may change the final answer.
What service size is typical for a modern home?
Many newer all-electric homes land near 200A service, especially with EV charging, electric dryers, large HVAC loads, or hot tubs. Smaller homes with gas appliances may still fit comfortably on 100A or 150A.
Can I add custom loads?
Yes. Use the custom-load button for specialty equipment, workshops, detached buildings, or any appliance not already listed in the common checklist above.
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