Use one all winter long, ezbtr. It's in the huge master bath that has a 4' square skylight. It's not exactly like yours but the same idea. I have it on a heavy duty Intermatic timer so it comes on every morning before I need to go in for morning duties. We will also turn in on in the late evening for night time duties. I also have a little 750/1500 watt heater on the dashboard of my service van. I ran a cord out thru the firewall to the grille. In the garage I have another timer (on the ceiling) and a cord that runs out under the garage door. On nites I know it will be cold, frosty or snowing, I plug that cord into the grille plug and the timer kicks on at 5 am. By the time I need to leave, the windshield is clear and dry and the cab is tolerable.
I an not so sure it is anymore economical than the heat pump HVAC, but it allows you to target smaller areas without having to run the HVAC at full blast.
I am skeptical about any claims of economy for any small space heaters. A watt is a watt, no matter how you try to claim it.
