What Size Generator Do You Need to Run a Wet and Dry Vacuum?
By the Generator Size Calculator Team · Updated · 5 min read
Quick answer: Honda lists a wet and dry vacuum at 900 watts for 1.7 hp and 1,300 watts for 2.5 hp, with no start-up surge. A 2,000-watt inverter runs the smaller one and a 2,500-watt generator the larger. Add a dehumidifier and a light for cleanup and a 3,000-watt generator is the comfortable size. Keep the generator and its cords out of any water.
Wet and dry vacuum watts
| Vacuum | Running watts | Starting watts |
|---|---|---|
| Wet and dry vacuum, 1.7 hp | 900 | 900 |
| Wet and dry vacuum, 2.5 hp | 1,300 | 1,300 |
| Household vacuum, upright | 800 | 1,100 |
| Household vacuum, canister | 1,100 | 1,500 |
These are Honda's typical figures. The household rows are for comparison and are covered in what size generator runs a vacuum cleaner.
Which generator size to choose
| Vacuum | Generator |
|---|---|
| 1.7 hp (900 W) | 2,000 W inverter |
| 2.5 hp (1,300 W) | 2,500 W |
Sizes keep the running load under 80% of the rating. A 900-watt vacuum needs a rating of at least 1,125 watts, and a 1,300-watt one at least 1,625 watts, which rounds up to 2,500.
Example: vacuum, dehumidifier and light
| Load | Running watts |
|---|---|
| Wet and dry vacuum, 2.5 hp | 1,300 |
| Dehumidifier | 650 |
| Work light | 100 |
| Running total | 2,050 |
The dehumidifier's extra start-up load is 150 watts (800 minus 650), so the peak is about 2,200 watts. A 3,000-watt generator carries 2,050 running watts under its 80% mark (2,400 watts), and its approximate 3,750-watt starting capacity covers the peak. The light is an example value. See what size generator runs a dehumidifier.
Include a fan, a pump and lights.
Wet-work safety
- Keep the generator dry, outdoors and off wet ground. See can you run a generator in the rain.
- Use GFCI protection and outdoor-rated cords, with plugs kept out of standing water.
- Check the vacuum's label. Use a wet-rated vacuum for water.
Run the generator outdoors, at least 20 feet from doors, windows and vents. Never in a garage or shed, even with the door open. See how far a generator should be from your house.
Frequently asked questions
How many watts does a wet and dry vacuum use?
Honda lists a 1.7 hp wet and dry vacuum at 900 watts and a 2.5 hp one at 1,300 watts.
Can a 2000-watt generator run a shop vac?
A 1.7 hp one, yes. A 2.5 hp vacuum at 1,300 watts is above the 80% mark of a typical 2,000-watt inverter, so a 2,500-watt generator is safer.
Do shop vacs have a starting surge?
Honda lists the same starting and running watts, so no extra surge.
Can I run a shop vac and a dehumidifier together?
Yes, on about a 3,000-watt generator with a work light.
Is it safe to use a generator for water cleanup?
Only outdoors, dry, with GFCI protection and no cords in water. If wiring may be wet, ask an electrician.
Related calculators
Sources: Running and starting watts from the Honda generator wattage guide (wet and dry vacuums, household vacuums, dehumidifier). Generator sizes apply the 80% running rule and an assumed starting capacity about 25% above the running rating. The work light in the example is an assumed value.