Do I need an electrical panel upgrade?
Not always. An upgrade is likely when the calculated load of your home plus the new equipment goes over the service rating. A quick estimate tells you what to ask about.
Reading the result
| Fits | 80% of the service rating or less. An upgrade is less likely, but confirm with an electrician. |
| Tight | Between 80% and 100%. Ask about smaller equipment, load management or an upgrade. |
| Over | Above 100%. An upgrade or a change to other loads is likely needed. |
Worked example: EV charger and heat pump together
Illustrative home, not yours: 1,800 sq ft, electric range (12,000 VA), electric dryer (5,000 VA), electric water heater (4,500 VA), 2,000 VA of other fixed appliances and a 4,000 VA central A/C.
| General loads: lighting at 3 VA per sq ft, two 1,500 VA small-appliance circuits, 1,500 VA laundry, plus range, dryer, water heater and other fixed appliances, plus the charger (40 A x 240 V x 125% = 12,000 VA) | 45,400 VA |
| First 8,000 VA at 100%, the rest at 40% | 22,960 VA |
| Heat pump (3 tons at about 1,200 VA per ton) in place of central A/C | 3,600 VA |
| Total, divided by 240 V | 110.7 A |
| Against a 100 A service | 111% (over, above 100%) |
On a 200 A service the same home reads 55%.
How Panel Check estimates it
Panel Check uses an NEC-style optional method for existing homes. It adds general loads, counts the first 8,000 VA in full and the remainder at 40%, adds the larger of cooling or heating, then divides by 240 V to get amps. An EV charger is treated as a continuous load, so its breaker size is multiplied by 125%. A result at or under 80% of the service rating reads as fits, up to 100% as tight, and above that as over. The heat pump figure is a rule of thumb; the nameplate on your equipment is the real number.
Frequently asked questions
What does a panel upgrade involve?
It can mean a larger main breaker, a new panel, or a larger utility service. Scope and cost vary, so get written quotes from licensed electricians.
Are there alternatives to an upgrade?
Sometimes. A lower-amp charger or other load changes can help. An electrician can tell you which are allowed where you live.
Does the estimate replace an electrician visit?
No. It prepares you for the visit. The electrician measures and calculates your actual home.
Try it on your own numbers
This is a planning estimate, not an electrical design. A licensed electrician must confirm your actual panel, wiring and local code requirements before any work. Nothing here is a guarantee of safety or code compliance.