Estimate solar capacity, panel count and battery storage for a small home—with simple questions about your home and everyday habits.
Free planning estimate · Small homes from 150–1,200 sq ft · Five US location examples
Solar & battery estimate
Explore covering the selected month’s daily electricity use. Winter coverage can require much more solar than a grid-connected system designed around annual savings.
Example ready · Step 1 of 3
We’ve set up a modern 500 sq ft home for two adults. Check what fits yours; everyday appliance habits are already filled in below.
Adjust everyday habits
Averages include a fridge, lights, coffee, microwave and small loads. Laundry and dishwasher use are spread across the week. Internet budgets assume 15 W for broadband or 100 W for Starlink plus router; your equipment may differ.
“Not sure” gives a wider range. Gas, propane and wood options estimate their electrical demand only; fuel use is separate.
These five cities are examples, not a lookup for your address. Location and season affect sunlight and the heating/cooling scenarios. Check your actual site before choosing equipment.
Advanced assumptions
Midday/evening presets assume 45%/65% of daily energy passes through the battery. They do not simulate hourly solar surplus. Solar models use a 25° south-facing roof and 14% losses; extra site loss is applied afterwards. Backup assumes zero generation and includes recharge over the chosen number of average solar days. Panel rating defaults to 450 W. All are adjustable assumptions.
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Your daily energy range
Bars show the higher-use scenario. Labels show both scenarios where assumptions differ.
These combine lower-use assumptions at one end and higher-use assumptions at the other. The upper number is not the expected size for every ADU; neither endpoint is a guaranteed bound. Insulation, comfort settings, showers, humidity and actual equipment can move consumption outside the range.
Daily kWh cannot tell you whether the inverter can run cooking, heating and other large loads together. Check continuous power, surge demand, voltage and equipment compatibility.
This is a monthly energy-coverage calculation, not proof of self-sufficiency. A smaller solar array can still help a grid-connected home. A monthly-average energy balance cannot guarantee overnight cover or off-grid operation through cloudy spells. Roof area, shading, snow, hourly demand and equipment limits need a site-specific design.
Explore home solar panels
Compare panel wattages and dimensions at A1 SolarStore, then confirm the complete system with your installer.
Explore solar panelsCheck current stock, delivery costs and minimum order quantities for your location.
How this estimate works
PVWatts AC output already includes the modelled inverter losses. The additional battery round-trip factor applies only to energy routed through storage. Reserve reduces available capacity; it is not charged as an extra daily loss. Battery result uses a generic nominal DC rating; a product’s usable AC rating needs a different comparison.
Guided climate assumptions: a square, single-storey home, 2.4 m ceilings and windows equal to 20% of wall area. Insulation choices set broad assumed heat-loss ranges. Hourly outdoor temperatures produce heating degree-hours below 18°C and cooling degree-hours above 24°C. Heat-pump heating uses assumed efficiency (COP) 2–4; cooling uses 2.5–4 plus an assumed internal/solar heat allowance. This is a simplified scenario model, not a Manual J calculation; cold-weather backup heat, humidity, defrost and actual equipment performance need separate assessment. Hot-water and dryer use also use assumed ranges. The reader-facing tool estimates these from your home and equipment choices; it asks for no daily heating or hot-water energy figure.
Location data: PVWatts v8.5.0, NSRDB TMY weather, retrieved 8 October 2026. Linear scaling assumes the same array orientation, loss inputs and DC/AC ratio. The model is not affiliated with or endorsed by DOE/NLR.
What would your appliances use?
Follow two adults and a dog through a solar-powered ADU day, including appliance timing and winter limits.
Explore the dayThis is an illustrative planning tool. Confirm your actual climate, energy use, roof layout and equipment power with a qualified installer before choosing a system.
