Check the appliances you want to power during an outage. Adjust the running and starting watts if your appliance nameplate differs from the defaults.
| Include | Appliance | Running (W) | Starting (W) |
|---|---|---|---|
| Refrigerator / Freezer | |||
| Sump pump | |||
| Well pump | |||
| Furnace fan (gas furnace blower) | |||
| Window AC (10,000 BTU) | |||
| Central AC (3 ton) * | |||
| Space heater | |||
| Chest freezer | |||
| Microwave | |||
| Lights (per 100W of bulbs) | |||
| TV | |||
| Laptop / phone chargers | |||
| Shop power tools (circular saw) | |||
| Washing machine | |||
| Garage door opener |
* Central AC units this large typically need a dedicated whole-house standby generator — this entry is included for reference.
| Metric | Value |
|---|
Hoe de berekening werkt
This calculator sums the running watts of every appliance you check, then finds the single checked appliance with the largest starting (surge) watts.
Only that one appliance contributes its starting surge to the total — everything else is assumed to already be running steadily, since motors rarely all start at the exact same instant. A 20% safety margin is added, then the result is rounded up to the nearest standard generator size.
Safety: never run a generator indoors or in a garage — carbon monoxide from the exhaust can be fatal in an enclosed space. Backfeeding a house panel safely requires a transfer switch installed by a licensed electrician. This tool is for sizing only, not an electrical installation guide.