How we estimate your power needs

Gridwise is a planning prototype. All product specifications and reference prices are illustrative and unverified. Confirm exact regional models, connectors, voltage, surge duration and charging limits with official manufacturer documentation.

Battery-only runtime

Average appliance power = sum of running watts × duty cycle. Usable energy = rated Wh × 90% conversion efficiency × temperature factor × (1 − reserve). Runtime in hours = usable energy ÷ (average appliance watts + 10W inverter idle draw). No appliances means no runtime estimate.

Temperature factors are 70% below 0°C, 85% below 10°C and 100% otherwise. These simplified assumptions are not manufacturer discharge curves. Charging below freezing requires explicit manufacturer support.

Running and startup power

Continuous demand is the sum of appliance running watts. Conservative simultaneous startup demand is the sum of each appliance’s larger value of startup surge or running watts. Duty cycles do not reduce required inverter ratings. Editable startup values should come from the device label, a datasheet, or measurement.

Overload recommendations must satisfy both continuous and surge limits. They do not model surge duration, power factor, motor behavior or start sequencing; verify these separately. If the catalog contains no match, we show required minimum ratings.

Solar harvest

The simulator models parallel wiring only. Operating current adds; voltage does not. Cold open-circuit voltage = panel Voc × [1 + voltage temperature coefficient ÷ 100 × (ambient °C − 25)]. Arrays outside sample voltage or current limits produce no estimated harvest.

Solar watts = the minimum of 80% of array nameplate watts, station solar watt limit, and station current limit × panel operating voltage. Daily harvest = solar watts × peak sun hours. Solar is excluded from battery-only runtime; daily coverage does not prove uninterrupted overnight operation.

Electrical installation

Never backfeed a wall outlet. Furnace integration may need a neutral-ground bond and a professionally installed transfer switch. The calculator does not certify installation safety or guarantee medical-device runtime.

Prices and availability

Purchase links, once configured, use “Check current price.” No live prices or stock are claimed. Illustrative internal price values only order recommendations; a larger battery alone does not resolve an inverter overload.