One of the beast ways to determine required heater size is to experiment.
A 1500 watt electric heater provides a little more than 5,000 BTUs. If it
provide enough heat, than the HS2000 will be enough. From experience this
should be good down to just below freezing. If you want to camp in colder
temperatures, and/or want fast warm up, then go for the 2800. Keep in mind
these ratings are the BTU or fuel input. The actual heat to transfer
inside will be ~20% less. You will also need adequate battery capacity to
run it and do consider propane consumption.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Christopher Gronski
Sent: Sunday, July 29, 2007 4:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Time to think about winter

I have a Eberspacher B1L (NOS still in shrink wrap) that I plan to
sell on eBay in order to buy one of Karl's propex furnaces, It's 1800W
(6143.4 BTU). I was all set to install the B1L and then stopped
because I know one day I want to go diesel and I don't want to have to
change the heater again (or carry two fuels).

I think Karl's HS2000 at 6500 BTU would be plenty warm enough,
although the HS2800 at 9500 BTU might allow you to keep your pop top
up a little later in the season. If money is an issue go for the
HS2000, but fme I like overkill so when I get mine I'll pay the extra
$200 for the HS2800.

Chris

On 7/29/07, Tom Buese <tombuese@comcast.net> wrote:
> Since its really hot outside, I am starting to think about winter &
> installing 1 of Karl's propex furnaces.  I see on his website, that
> there are 2 models.  What's the opinion of this august group,
> especially you Canuckians, on the proper size furnace?  Will the $700
> model (6.5k btu)keep us nice & toasty, possible in the NE in mid
> winter, or do I need the $900 (9k btu)model?
>
> Tom B.-Wave 3000 didn't cut it at my coldest (28 degrees +-) campout
> this year, January in Lake Havasu City, AZ.
>