Daily Energy Usage Calculator
See your home's energy use hour by hour. Edit watts for each time slot — instantly see daily totals, monthly cost, and your peak demand.
| Time | Watts | Load bar | Wh |
|---|---|---|---|
| Morning (6am) | 0.800 kWh | ||
| Breakfast (7am) | 1.500 kWh | ||
| Daytime low (8am) | 0.300 kWh | ||
| Daytime low (9am) | 0.300 kWh | ||
| Daytime low (10am) | 0.300 kWh | ||
| Daytime low (11am) | 0.300 kWh | ||
| Midday (12pm) | 0.600 kWh | ||
| Afternoon (1pm) | 0.400 kWh | ||
| Afternoon (2pm) | 0.400 kWh | ||
| Afternoon (3pm) | 0.400 kWh | ||
| Late afternoon (4pm) | 0.600 kWh | ||
| Evening prep (5pm) | 1.200 kWh | ||
| Evening (6pm) | 2.000 kWh | ||
| Evening (7pm) | 1.800 kWh | ||
| Evening (8pm) | 1.500 kWh | ||
| Evening (9pm) | 1.200 kWh | ||
| Night (10pm) | 0.600 kWh | ||
| Night (11pm) | 0.300 kWh | ||
| Midnight (12am) | 0.150 kWh | ||
| Night (1am) | 0.150 kWh | ||
| Night (2am) | 0.150 kWh | ||
| Night (3am) | 0.150 kWh | ||
| Night (4am) | 0.150 kWh | ||
| Early morning (5am) | 0.400 kWh |
How to Use This Calculator
Enter your hourly load profile
Each row represents one hour of the day. Enter the average watts your home consumes during that hour. Include everything running: appliances, HVAC, lighting, electronics, and standby loads. The load bar turns red for your highest-load hours — these are the hours that most impact your peak demand and solar sizing.
Use realistic watt estimates
Sleeping hours (midnight–6 AM): 100–200W (fridge, standby devices, router). Morning routine (6–8 AM): 600–1,500W (shower, lights, coffee maker). Daytime if home: 300–600W. Evening peak (6–9 PM): 1,500–3,000W (cooking, TV, lights, AC/heat). Check appliance nameplates or a smart plug for accurate readings.
Enter your electricity rate
Enter your cost per kWh. Check your utility bill — the US average is ~$0.15/kWh but ranges from $0.10 (Louisiana) to $0.35+ (Hawaii). This converts your kWh totals into dollar figures.
The Formula
This is a load profile approach rather than an appliance inventory. It captures actual behavior — a gas stove that runs for 30 minutes shows as a partial contribution, and a fridge that cycles on/off shows as its average draw (~150W). The peak hour shows your maximum instantaneous demand, important for inverter and breaker sizing.
Example: Average US Home
3-bedroom home, family of 4, Southeast US
Gas furnace but electric AC, LED lighting, standard appliances. Work-from-home setup.
Result
This load profile shows that solar production hours (10 AM–3 PM) mostly cover 400–600W loads, while the 1,500–2,000W evening peak falls after sunset. A battery would capture midday solar and shift it to the 6–9 PM peak — the strongest TOU arbitrage opportunity.
Why a Load Profile Matters for Solar
Knowing your hourly profile tells you more than just total consumption:
- Solar self-consumption: Loads during 10 AM–3 PM can be powered directly by solar. The rest requires grid or battery power.
- Battery sizing: If your evening loads are 1,500W for 5 hours, you need 7.5 kWh of usable battery to cover them.
- Inverter sizing: Your peak demand hour determines minimum inverter capacity. A 2,000W peak needs at least a 3,000W inverter (with surge margin).
- Off-grid feasibility: Off-grid systems must cover every hour. Your overnight baseload (fridge, router, lights) determines battery minimum capacity.