Warm like sun on a winter morning.
GLN warms you directly, the way sunlight does, instead of blowing hot air around the room.
Cool like shade in summer.
In summer the same panels draw heat out of the room. No fan, no vents, no draft.
Illustrative render
Warmth that reaches you
Winter sun warms your face even when the air is cold, because the heat travels to you directly. GLN panels work the same way: they bring the surfaces of a room to a comfortable temperature, and the warmth reaches you without any air being blown around.
How warm a room feels is roughly the average of the air temperature and the temperature of the surfaces around you. With warm surfaces, the air can be a little cooler and the room still feels warm. In summer it runs the other way: air at 27 °C with walls at 22 °C feels about 24.5 °C.