Off-grid planning tool

Tiny House Solar Calculator

Estimate daily energy use, battery capacity, solar panel wattage, inverter output, and a few system options that fit your numbers.

Battery capacity and inverter output are separate

Battery capacity, measured in kWh, estimates how long your power lasts. Inverter output, measured in watts or kW, estimates what can run at the same time. A large battery can still struggle if the inverter is too small for appliances that start together.

Appliances

Add the devices you expect to run in your tiny house. Presets are planning estimates and every row stays editable.

Appliance	Watts	Startup watts	Hours/day	Qty	Daily Wh	Remove

Startup watts are optional. If left at 0, the calculator uses normal watts for peak inverter sizing. Use whole numbers for quantity. Decimals round to the nearest whole number.

Fridge cycling: refrigerators do not pull their full wattage all day. Presets use 8 hours/day as a simple planning average.

Vampire power: always-on items like routers, chargers, clocks, and standby electronics can quietly add up over 24 hours.

System settings

Use local solar conditions and your preferred backup assumptions.

Battery backup days How many cloudy days the batteries should cover.

State sun-hours estimate Planning estimate by state. Peak sun hours

System efficiency (%) Accounts for real-world losses from wiring, inverter use, heat, and charging. Battery depth of discharge (%) Usable share of the battery before recharge. Inverter safety margin (%) Extra room above estimated peak load.

Estimates for year-round planning. Winter sun hours are lower - if you'll rely on solar in winter, subtract about 1 to 1.5 hours or size up.

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Estimated results

Total daily energy 0 Wh 0 kWh per day

Battery capacity needed 0 Wh 0 kWh needed for backup time

Solar panel size 0 W Needed to recharge daily use based on sun hours and system efficiency.

Estimated peak load 0 W Running load plus any startup watts entered for motors, pumps, fridges, or microwaves.

Inverter output needed 0 W Based on estimated peak load plus the inverter safety margin.

Systems that fit your numbers

These are planning matches based on your battery, solar, and inverter estimates. Always confirm final sizing before buying equipment.

This calculator gives a rough planning estimate only. It is not a final electrical design. Consult a qualified electrician or solar professional before buying or installing equipment.