What Can a 5500 Watt Generator Run?
Check the appliances you want to keep on during an outage and see whether a 5,500 W generator can start them and keep them running together.
What can a 5,500 W generator run
E03Scenario A
On a 5,500 W generator
1,500 W to spare at the starting peak.
- Usable capacity (90%)
- 4,950 W
- Running load selected
- 1,950 W
- Peak when the largest motor starts
- 3,450 W
- Does it fit?
- Yes
Estimate. Formula and sources are under “How it works”. Change any input; the result updates as you type.
Formula
How it works
- Usable capacity = generator watts × 0.9 (we keep 10% in reserve)
- Running load = the sum of the running watts of everything you checked
- Starting peak = running load + the largest extra starting surge among the checked appliances
- It fits when the starting peak is at or below the usable capacity
Only the single largest surge is added, because motors rarely start at the same instant. If two big motors kick on together, the peak is higher: start them one at a time.
Sources: running and starting watts from manufacturer sizing tables (Generac) and DOE; motors typically draw 2–3 times their running watts to start. The 90% usable margin is our planning assumption.
Appliance watts and combination table
Identical to E03-3500.md (same 16-row appliance table; same "what fits, by generator size" table with the 5,500 W column highlighted).
Worked example
A worked example
A 5,500 W generator has about 4,950 W usable. The refrigerator, a 1/2 HP sump pump, 10 LED bulbs and the TV and router run at 1,950 W together. When the fridge compressor starts, the peak reaches 3,450 W. Verdict: yes, it fits, with about 1,500 W of room left for a furnace fan or a microwave used on its own.
Questions
FAQ
Can a 5500 watt generator run a refrigerator and AC?
A refrigerator plus a 10,000 BTU window AC, yes: 1,900 W running and a 4,300 W start, under the 4,950 W usable. Add a microwave and the start reaches 5,300 W, which doesn't fit. A 3-ton central AC doesn't fit on 5,500 W: its start alone needs about 7,000 W.
Can I run a well pump on a 5500 watt generator?
A 1 HP well pump plus a refrigerator runs at 1,700 W and peaks at 3,700 W, so yes. Keep other motors off when the pump kicks on.
Can a 5500 watt generator run a space heater?
A 1,500 W space heater plus the refrigerator peaks at 3,700 W, which fits. It's also the fastest way to burn fuel: 1,500 W is a large share of a 5,500 W generator's output. See what that costs on the generator fuel cost page.
Running vs starting watts: what's the difference?
Running watts are what an appliance draws once it's going. Starting watts are the brief surge a motor needs to get turning, typically 2–3 times the running figure. A generator must cover the running load plus the biggest surge.
Can a 5500 watt generator power a whole house?
It covers the essentials of most homes, not everything at once. An electric water heater (4,500 W) or an electric dryer (5,000 W) takes nearly all of it by itself. Connecting a generator to house wiring needs a transfer switch or an interlock installed by an electrician.
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