"mm" wrote in message

How does this apply to auto heaters?

You're the first person I've seen mention that one can get iiuyouc,
almost the same result with lower velocity and higher temp.

I like to put my car fan on one of the lower two speeds, because it
makes too much noise in the higher two.

I figure that at lower speeds, the air spends more time in the heater
core, and gets hotter, so that makes up for the fact that there is
less hot air.

Am I right, and do you have a guess about how much heat speed 2 puts
out compared to speed 3? It's a Chrysler at the moment.

Any auto with automatic heat starts the blower on low speed when the water
hits about 110 degrees. This gets heat into the car as soon as possible,
but at lower volumes. On mine, it steps up again at about 125 and again at
about 150.

In any case, there is only so much heat available at a given temperature of
the heating coil. Lower speeds give a higher relative air temperature due to
the increased residence time, but overall heat output would be less than the
optimal combination of coil temperature and air flow.