Why there is something rattling inside the heater when shaken?
No worries, it is normal. Because the built-in tip-over switch inside the heater will rattle when its shaken. It is not a quality problem.
How long is the power cord?
he power cord is 5.2 feet.
Can the oscillation be turned off?
Yes, you can just clockwise rotate the control knob from "WARM" mode or "HOT" mode with arrow above it to "WARM" mode or "HOT" mode.
Is it safe to use the N1 space heater on the wood table?
Yes, it is safe. Do not worry about this because the temperature in the base will not too high.
How and how often does the filter need to be cleaned?
The filter is detachable and washable. It is recommended to clean the filter once or twice in a month. Please just make sure its dry when you put back in.