Smart Home Load Planner — Panel Size Advisor
Select your current and planned electrical devices to calculate total demand and find the right panel size for your smart home.
Select Your Devices & Appliances
Planning Your Smart Home Electrical System
The modern smart home is an electrical powerhouse. A typical 2020-era home drew 60-80A of peak demand. A 2026 all-electric smart home with EV charging, heat pump HVAC, induction cooking, and a home office easily demands 150-250A. The key to avoiding expensive panel upgrades later is planning ahead — size your electrical service for where you will be in 5-10 years, not just today.
This calculator uses a simplified version of NEC Article 220 load calculations. It applies the 125% continuous load multiplier (NEC 210.19) to loads that operate for 3+ hours (EV chargers, heat pumps, pool pumps) and sums non-continuous loads at 100%. The recommended panel size includes margin for future additions. For a formal load calculation required for permits, consult a licensed electrician.
Common Smart Home Configurations
Starter smart home (100A panel OK): Base load + central AC + smart thermostat + smart lighting. Total demand: ~65A. A 100A panel handles this with room to spare.
Modern smart home (200A panel): Base load + heat pump + electric water heater + EV charger + induction range + smart everything. Total demand: ~170A. The 200A panel is the sweet spot for most families with one EV.
Full smart home (320A+ panel): Everything above + second EV charger + hot tub + workshop + home server. Total demand: ~280A+. Requires 320A or 400A service, typically implemented as dual 200A panels.
Five Load Planning Mistakes
1. Forgetting the 125% rule. A 48A EV charger requires a 60A circuit, not 50A. The 125% continuous load rule adds up fast — three continuous loads add 75% more demand than you might expect.
2. Planning for today only. Installing a 200A panel when you might need 320A in 3 years wastes money. The panel itself costs 500-1,000 USD more; the labor to upgrade again costs 2,000-3,000 USD.
3. Ignoring diversity factors. Not all loads run simultaneously. NEC 220 demand factors account for this — a 50A range rarely draws 50A continuously. Professional load calcs use these factors; this calculator uses conservative estimates.
4. Overlooking the service entrance. Your panel rating means nothing if the service entrance cable and meter cannot handle the load. A 400A panel on a 200A service entrance is bottlenecked at 200A.
5. Not planning circuit routing. A finished home with drywall makes running new circuits expensive (500-1,500 USD per circuit through finished walls). During renovation or new construction, pre-wire for all planned circuits — the wire is cheap, the labor to open and patch walls later is not.