Diagnosis
The ceramic heating element isn't energizing. This is usually because the thermostat on the unit is set too low, the internal high-limit safety has tripped, or the element itself has failed.
How to Fix It
Start with the simple stuff. Make sure the thermostat dial on top isn't turned all the way to the 'Min' or 'Low' position. Turn it to a higher setting, like the middle. Also, check that the 'Heat' setting is selected, not just 'Fan'. Let the unit sit unplugged for at least 30 minutes to allow any internal safety fuses to cool and reset. Then plug it back in and try again on a medium heat setting.
If That Didn't Work
The ceramic heating element or its connection could be the issue. There's no user-serviceable fix for this. If the fan runs but you get zero heat after the steps above and on multiple outlet settings, the internal heating assembly has likely failed and you'll need to contact Lasko for repair or replacement.
Heads Up
These heaters have a built-in delay. When you first turn on the heat, the fan will start immediately, but it takes 15-30 seconds for the ceramic plates to get hot enough for you to feel warm air. Don't mistake this normal delay for a failure.