Integrated home energy planner guide
What does this calculator help you figure out?
Most calculators look at one thing — a bill, a battery, a solar array. This planner puts them together for a single day so you can see how home consumption, EV charging, solar generation, battery storage, and the grid interact. Enter daily electricity use, usable solar generation, the battery’s usable capacity with its starting charge and reserve, EV miles and efficiency, and your tariff: import rate, optional peak rate and peak share, export credit, fixed monthly charge, and energy tax. The daily mode meets demand from solar first, then from the battery (between its starting charge and its reserve), and imports the rest from the grid; any surplus solar is exported at 90 percent of the raw figure to reflect clipping and self-consumption timing. If you paste two 24-value kWh profiles, the planner switches to an hourly simulation with a 16:00–22:00 peak window and a battery power limit. It also shows how many hours the battery would carry a stated essential load in an outage, which is useful for load-shedding planning. Treat it as a planning scenario, not a design or a bill.
How is the result calculated?
EV energy (kWh) = EV miles ÷ EV efficiency (mi/kWh). Demand = home use + EV energy. Deficit = max(0, demand − solar). Battery contribution = min(deficit, usable battery × (starting charge − reserve) ÷ 100). Grid import = deficit − battery contribution. Export = max(0, solar − demand) × 0.9. Daily net cost = (peak import × peak rate + off-peak import × grid rate − export × export credit) × (1 + tax ÷ 100) + fixed monthly ÷ 30. Backup hours = usable battery × (100 − reserve) ÷ 100 ÷ essential load (kW).
Worked example
Worked example with the defaults: 20 kWh/day home use, 12 kWh/day solar, a 10 kWh battery starting at 80% with a 20% reserve, 40 miles of EV driving at 3.5 mi/kWh, $0.16 per kWh import, $0.05 export credit, no peak rate, fixed charge, or tax. EV energy = 40 ÷ 3.5 = 11.4 kWh. Demand = 20 + 11.4 = 31.4 kWh. Deficit after solar = 31.4 − 12 = 19.4 kWh. Battery available = 10 × (80 − 20) ÷ 100 = 6 kWh, so grid import = 19.43 − 6 = 13.43 kWh and there is no export. Cost = 13.43 × $0.16 = $2.15 per day, the figure the planner displays. Essential-load backup = 10 × 0.8 ÷ 1 kW = 8 hours.
Units and conversion notes
Home use and solar generation are in kWh per day; take home use from your bill (monthly kWh ÷ 30) and solar from the solar-generation calculator. Battery capacity is usable kWh, with charge, reserve, and peak share as percentages; the battery power limit is kW and only applies in hourly mode (0 means unlimited). EV driving is miles per day and efficiency is miles per kWh — for km, divide km by 1.609 and use km/kWh ÷ 1.609. Rates are currency per kWh, the fixed charge is per month, and the tax is a percentage applied to the energy cost. Hourly profiles are 24 comma- or space-separated kWh values.
What does the result mean?
This is a modelled estimate, not a meter reading. Real consumption moves with weather, occupancy, appliance age, standing charges, and tariff structure, and equipment rarely runs at its nameplate rating. Use the figure to compare options against each other, then confirm against your own bill and the manufacturer's specification before committing to a purchase. On this page the figure rests entirely on home electricity use, usable solar generation, usable battery capacity, battery starting charge, battery reserve, battery/inverter power limit, essential backup load, ev driving, ev efficiency, grid import rate, peak import rate, peak import share, solar export credit, fixed monthly charge, energy tax, optional 24-hour load profile (kwh), optional 24-hour solar profile (kwh), market / jurisdiction, effective date, data source, update owner and review date, so start there if the integrated home energy planner returns something you did not expect.
Common mistakes to avoid
Good to know: a battery does not add energy — with 12 kWh of solar and 31 kWh of demand it only shifts 6 kWh from grid to storage, so the daily cost barely moves unless a peak rate makes those 6 kWh expensive. Entering the battery’s nominal capacity instead of its usable capacity, or a starting charge of 100 percent every day, overstates its contribution. Export at $0.05 rarely pays for an oversized array; the planner shows this when you raise solar past demand. In hourly mode, forgetting the power limit lets a 5 kWh battery “deliver” 5 kW in one hour, which most units cannot.
Energy results depend on tariffs, equipment behavior, region, weather, and installation assumptions. Verify rates and electrical decisions with the utility, manufacturer, or qualified professional.
