Engine Preheater - any good?

George Patterson wrote:

If it's really putting out air at 190 degrees, it's not any heater
you can buy at a retail outlet.

It puts out 500, 1000, or 1500 watts, which oddly enough are the same
power settings as on my Kmart "preheater". A weaker fan will result in
a higher temperature, a stronger fan a lower one. The temperature
itself is meaningless to someone trying to figure out how well this
thing is going to work. Marketing hype.

A claim is also made that it has a thermostat that will
regulate the unit. The thermostats on typical heaters designed for
home use measure the ambient temperature of the air in the room, not
the temperature of the air flowing through the unit. This is, of
course, a function of the location of the thermostat, but someone
had to do some design work here.

Not convincing. The temperature of the air is irrelevant. What matters
is the temperature of the engine and the oil.

Seems to me to be somewhat more effort involved than just putting
together a few off-the-shelf parts.

Maybe you're not cynical enough. Then again, maybe I'm too cynical.
Considering the other options available though (e.g. my cheap-ass
solution, or Red Dragon), $299 is a chunk of change for something like
this.
:
Jim Rosinski

Jim Rosinski wrote:

George Patterson wrote:


If it's really putting out air at 190 degrees, it's not any heater
you can buy at a retail outlet.


It puts out 500, 1000, or 1500 watts, which oddly enough are the same
power settings as on my Kmart "preheater". A weaker fan will result in
a higher temperature, a stronger fan a lower one. The temperature
itself is meaningless to someone trying to figure out how well this
thing is going to work. Marketing hype.

Yes, the temperature is meaningless up to a point. If it moves so much
air that the temperature never gets more than 5 degrees above ambient,
then it won't be a very good preheater. However, if the temperature of
the output air is at least as high as what you wish your engine
temperature to be, then it is heat output that matters rather than
temperature of the air.


A claim is also made that it has a thermostat that will
regulate the unit. The thermostats on typical heaters designed for
home use measure the ambient temperature of the air in the room, not
the temperature of the air flowing through the unit. This is, of
course, a function of the location of the thermostat, but someone
had to do some design work here.


Not convincing. The temperature of the air is irrelevant. What matters
is the temperature of the engine and the oil.

Yes, but the temperature of the air has an affect on that of the engine
and oil. The air temp has to be AT LEAST as high as what you wish for
your engine.


Seems to me to be somewhat more effort involved than just putting
together a few off-the-shelf parts.


Maybe you're not cynical enough. Then again, maybe I'm too cynical.
Considering the other options available though (e.g. my cheap-ass
solution, or Red Dragon), $299 is a chunk of change for something like
this.

Yes, it is a chunk of change, so better to build your own. I did that
with a "milk house" heater, some aluminum roof flashing and some
flexible dryer duct. It wasn't pretty, but it did the job for probably
$50 in parts. However, I also probably spent 3 hours of time so when
you factor that in, the commercial units don't look quite so overpriced.


Matt