Hot air rises - so as fast as you heat the air - so it rises up into that ceiling space where it does nobody any good.
You have to heat up all of that air at the top of the room before it gets warm lower down where the people are.
Adding a ceiling fan will move hot air, but also creates a draft that makes you colder. Moving your HVAC vents lower, even to the floor, is okay if you plan on standing right next to the vent all day.
A Real Solution for High Ceilings Heating
Radiant Heat is Different
Radiant heat does not heat up the air directly like a hot air system does. Radiant heat warms objects and people directly.
Think of radiant heat like sunlight. It “shines” on all the objects and people it can see. That “shine” is what warms you and the objects within the room. Just like the Sun warms you directly on a clear day.
Directly, instantly and efficiently.
Ceiling height isn’t a factor in how far radiant heat can travel. Since radiant heat doesn’t heat the air directly, there’s no hot air rising (and no cold down drafts)in the room, and thus the warmth is evenly distributed throughout the space.
There’s no need for fans to move the heat to where you are—at the floor level. Radiant heat does its job effectively and efficiently.