Decision helper
Do you need a service upgrade?
A service upgrade costs thousands of dollars and is often not needed. Pick what your home has and what you plan to add. This helper compares your service with a simplified demand estimate and tells you whether to upgrade, manage the load, or leave it alone.
Your result
Start with your service size
The result appears once every list has an answer.
Why this result
What to do next
How this result is reached
| Result | When |
|---|---|
| No upgrade needed | The estimated demand stays at or below 80 percent of your service. |
| Tight: manage the load first | The estimated demand is between 80 and 100 percent of your service. |
| Plan a service upgrade | The estimated demand is above your service, or the service is 60 amps. |
| Find your service size first | You do not know the size of your service. |
The estimate. General load is 3 volt-amps per square foot plus 4,500 for the kitchen and laundry circuits. The range counts as 8 kW, the dryer as 5 kW, and the water heater at its rating. The first 10 kVA of these counts in full and the rest at 40 percent. Heating and cooling count in full. The EV charger counts in full: 11.5 kW when the car must be full in 5 hours or less, 3.8 kW when it can charge all night. The total is divided by 240 volts.
This is a simplified version of the optional method in the NEC, not a load calculation for a permit. A licensed electrician must do that for your home, and your local electrical inspector has the final word.