Methodology
The same math your electrician runs, in plain English
ChargeRight uses the NEC 220.82 optional load calculation - the same method a licensed electrician puts on a permit drawing. No black box. Every number behind your verdict is on the report.
What the calculation actually sums
The optional method gives the homeowner credit for what real homes really use, not the worst case the standard method assumes. It is in the code on purpose.
NEC 220.82 is the Optional Method for existing dwellings. It adds up your home's general lighting load, your fixed appliances at their nameplate ratings, the larger of heating or A/C per NEC 220.60, and the new EV circuit at the continuous-load sizing the code requires. The result tells you whether your existing service amperage covers the combined demand. I built ChargeRight to run this calculation for $12.99 instead of a service call.
General lighting and receptacle load
based on the size of your home, exactly the way the code prescribes it
Small appliance and laundry circuits
the code-required allowance for every small appliance and laundry circuit
Appliance nameplates
every fixed appliance you actually have, at its real nameplate rating
Heating or A/C - the larger of the two
NEC 220.60 lets the smaller load drop out, because they do not run at once
Electric heat strips
credited at the reduced factor 220.82(C) assigns when the conditions apply
The EV charger
sized for continuous load the way the code requires for a charging circuit
The demand factor
One demand factor is why most homes pass
After every load is summed, 220.82(B) lets a large share of the total drop to a reduced value, because a real home never runs everything at once. That single step is why most homes do not actually need a service upgrade when a charger gets added: a 200 amp service handles far more diverse, non-coincident load than a worst-case standard calc admits.
The code is public - you can read 220.82 at any library. What the report buys you is the calculation run correctly on YOUR panel: every threshold, every reduced factor, every intermediate number, applied where the code applies it and printed line by line. Bathroom branch circuits live in 210.11(C)(3), heat strips get their own reduced factor under 220.82(C), and the largest-motor surcharge belongs to the Standard method, not here. ChargeRight keeps each rule where the code keeps it.
Not an electrician? Your main panel is the gray metal box your meter feeds. ChargeRight checks if it has room for the charger before anyone upsizes it.
Three steps to a verdict
Add it all up
Sum the general load, every small appliance and laundry circuit, every fixed appliance nameplate, the larger of heat or A/C, and the new EV charger at its code-required continuous sizing.
Apply the optional demand factor
The code lets a big share of your total drop to a reduced percentage, because real homes never run everything at once. The exact thresholds and percentages are applied per 220.82(B) and printed on your report.
Compare to your service
If the demand-factored total fits under your panel rating, you can charge without upsizing the service. If it does not, you get an honest no with the exact number.
What the report tells you
- Whether your panel already has the capacity for the charger your car needs
- The exact circuit size to install (the 30, 40, 48, or 50 amp answer)
- A one-page report you can hand a licensed electrician for the install
- The math behind every number - not a black-box verdict
Run the math on your home
ChargeRight runs this exact calculation against your panel and your car. Get an honest verdict in a few minutes.
Check my panel$12.99 - results in minutes