Plan my backup system
Five-step wizard: what must run, size, source, inlet and wire, code edition, then a shareable plan link with verified models.
Tools
Free, no sign-up. Each tool answers one real question about backup power.
Backup power calculator
Pick appliances and outage length; get the battery size, power and surge you need, and which power stations fit.
CPAP battery backup
How long a power station runs a CPAP, with the calculator pre-filled.
Sump pump on a power station
What size battery keeps a sump pump going, including start-up surge.
Power station for a well pump: size, 240 V and surge
What size power station can run a well pump: typical watts, 240 V requirement, start-up surge and a worked runtime example.
Power station to work from home in an outage
What size power station keeps a laptop, router and lights running through an outage: typical watts, an hourly example and what a desktop PC adds.
Power station for a chest freezer: size and runtime
What size power station can run a chest freezer: typical watts, start-up surge, a worked runtime example and how long a closed freezer stays frozen.
Power station for a window AC: size and runtime
What size power station can run an 8,000 BTU window air conditioner: typical watts, start-up surge and a worked runtime example.
Run a fridge in an outage
Fridge runtime on a power station, using typical (labelled) draw.
What a 30 amp generator hookup can run
Typical appliances against the 30 A ceiling at 120 V and 240 V, with step-start logic.
What a 50 amp generator hookup can run
Typical appliances against the 50 A ceiling at 120 V and 240 V, with step-start logic.
What size wire for a 30 amp generator inlet?
Wire gauge by distance, copper and aluminum, from NEC 310.16 and voltage drop.
What size wire for a 50 amp generator inlet?
Wire gauge by distance, copper and aluminum, from NEC 310.16 and voltage drop.
Generator vs power station vs home battery
10-year cost of each option from your own prices and outage hours, with break-even and every assumption editable.
Generator fuel use and runtime
Gasoline, propane or natural gas use at your load, hours per tank, tanks for a 24 or 72 hour outage, and cost per day with your own fuel price.
What size generator do I need?
Tick your appliances; get running and starting watts with 30% headroom and the generator class to look for, working shown.
Critical loads panel planner
Tick the circuits to back up; get running watts and amps, worst-case start-up, start order and a printable subpanel circuit list.
Will my panel take it? Service load calculator
NEC 220.82 optional method: add a heat pump water heater, induction range, EV charger or battery and see if your service still passes, working shown.
Will my electrification package fit my panel?
Heat pump water heater, induction range, heat pump dryer or HVAC: NEC 220.83 and 220.87 check with 120 V and load-management options before you pay for a panel upgrade.
Electrification package builder
Tick several switches at once: yearly running cost, panel verdict and what the package does to your backup system, in one shareable link.
Appliance model lookup
Type a brand and model number to get its published watts, volts and amps with the source for each, edit anything, and see the backup size it needs.
Home battery and inverter size
Critical loads or whole house: usable kWh, inverter kW and surge, 120 V leg balance and whether you need 240 V.
Solar string and charge controller sizing
Cold-temperature Voc correction, max panels in series and parallel for a controller or power station input, NEC 690.7 and 690.8 cited.
Solar panel and battery sizing
Panels and battery for days of critical loads using worst-month sun, plus a reverse mode: roof area or budget in, kWh per day out.
Solar panels to recharge a power station
Panels needed to fill a station in your sun window, recharge time for panels you own, and a check against the station's max solar input.
Will these solar panels work with my station?
Check panel voltage and current against a station's solar window, and compare portable panels with a rooftop array by kWh a day.
Generator inlet breaker and wire size
2-pole breaker and feeder wire from inlet to panel, NEC 310.16, temperature correction and voltage drop, working shown.
One-line diagram builder
Pick inlet + interlock, station, standby generator or battery + solar; get a labelled diagram with breaker and wire size. Print or save as PNG.
Permit packet printer
One printable page: load summary, equipment list, one-line diagram and spec sheet checklist for an inlet with interlock.
Permit and inspection checklist
Documents to bring, what inspectors commonly check and inspection day prep, by project type. Printable.
Wire size and breaker size from a load
Amps or watts in, breaker and minimum copper or aluminum conductor out: 125% continuous rule, NEC 310.16, temperature and conduit derating, terminal limits, working shown.
DC battery cable and fuse size
Inverter watts and 12, 24 or 48 V in; fuse rating and minimum copper cable by ampacity and voltage drop out, working shown.
Conduit fill and size checker
Smallest EMT, PVC, rigid or flex conduit for your inlet or battery wires, NEC Chapter 9 Tables 1, 4 and 5, working shown.
Voltage drop calculator
Drop and smallest wire for long generator, shed and well pump runs from 12 V to 240 V, with a motor start-up check, NEC Chapter 9 Table 8, working shown.
Which NEC edition does my state use?
State-enforced NEC edition, effective date and local amendment notes, from state sources. Shows where we have no data yet.
Do I need a permit?
Permit requirement, issuing office and document list for generators, batteries and solar, city by city, from city pages. Shows where we have no data yet.
Generator inlet and cord matcher
Match your generator outlet to the right inlet, cord wire size and length, adapter warnings, and what the hookup can run.
Electrician quote checker
What a good inlet, interlock, generator, battery or solar quote should state. Tick what yours lists, get the gaps and a questions email.
Interlock vs transfer switch chooser
Which generator hookup fits your panel: interlock kit, manual transfer switch or automatic, with NEC 702 references.
Backup power incentives finder
Federal and state incentives for home batteries and solar, with primary sources and check dates. Shows where we have no data yet.
Generator placement and noise rules finder
Estimate generator dB(A) at distance against a city limit, with placement rules and the ordinance source.
Generator safety and placement checklist
Where to put a generator, CO alarm basics, and a cord gauge picker by amps and length.
Soft-start and surge check
Will a station or generator start your fridge, sump pump, well pump or AC? Start-up vs running watts, with and without a soft-start kit.
Will it run?
Pick a station with maker-verified specs and your appliances: runs, needs a soft-start kit, or will not run, with a typical runtime.
Medical device battery runtime
Oxygen concentrator, CPAP with heated humidifier and nebulizer: hours on a battery, with the safety steps to take with your supplier and utility. Oxygen guide · Nebulizer guide
Power station runtime calculator
How long will a verified model run your load? Hours of runtime, a table for a CPAP, router, TV, fridge and sump pump, and a check against output and surge ratings.
Runtime widget to embed
Free one-line script for blogs and forums: battery Wh and a device in, runtime out. No cookies.
Cost per kWh and cycle life
Compare up to 4 batteries by cost per usable kWh and per kWh delivered over rated cycle life, using your own price.
Appliance switch cost compare
Gas, propane or resistance versus heat pump water heater, heat pump dryer, induction cooktop or heat pump: yearly running cost at your prices, with a payback range.
Cold weather power station check
Will it charge and how much capacity is left at your lowest winter temperature? Maker temperature limits for verified models, plus a revised runtime.