Where did that 75% efficiency rating come from? Although it is probably
close. Looking at the btu input/output specs on the Propex site you get ~93%
which is really good for any furnace. At these high efficiencies you get
some water vapor condensation in the exhaust. Larger furnaces that work this
way are often known as condensing furnaces.

Consider that with the US style furnaces you get a lot more heat which means
run time will be a lot less.

For the Vanagon I like the Propex due to the small size and quiet operation.

The compression fitting should be replaced with a flare. It would be nice if
someone could get these UL or FM listed and make them main stream here in
the US.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Karl Mullendore
Sent: Thursday, October 29, 2009 10:32 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Suburban Type Furnace Install;

>
>Important to recognize is that furnace blowers draw current. This one, the
>16,000 btu Suburban NT-16SE, wants 2.8 amps when running. One hour of
>operation is 2.8 amp-hours, size your aux battery accordingly.

Also worth considering: the Atwood/Hydroflame furnaces are only 75%
efficient when running perfectly - Propex heaters are 95%. Throwing away a
gallon of propane for every three that results in heated air seems a bit
wasteful, not to mention fouling the environment more. Might that make the
efficient Propex a better deal in the long run?

Karl