You do realize a DB rise of 3 is double the volume...so your contractor's generator will be around 4 times as loud based on the spec you show.
Also are you comparing apples to apples noise specs?
- Check the distance it is estimated at.
- Check the throttle level assumptions.
A good chance the contractor's unit is estimated from a greater distance and at a lower throttle setting.
Then you have fuel economy and power quality:
- If the air/con (or other heavy load) is cycling on and off, the inverter generator will typically use much less fuel because it will throttle way back when the load is off. A traditional generator must keep the RPM up to provide a steady 60hz.
- Related to this, inverter generators generally are better at keeping the 120v-60hz power clean. Traditional generators tend to slow down and the voltage sags when you apply a heavy load before the engine can catch up.
10-15yrs ago, it was pretty much Honda/Yamaha if you wanted a quiet quality inverter generator...today, there are lots of options many much cheaper than the name brand, so going with the contractor type doesn't make a lot of sense.
