bus heat question

[4106-123]

can any one tell me about how many btu,s i would need  to heat my bus with the diesel fired coolant heaters like proheat? i was thinking of plumbing it to my defroster and then one more heater core in the middle of the bus. 4106 with pretty good insulation anyone heard of a superfex heater saw one for sale looks like military surplus?

[pvcces]

Nost RVers get by quite nicely on 40KBTU; a few have as much as 80KBTU.

There are a couple of reasons for choosing one or the other. While the smaller plant will heat the bus, if it is cold when turned on, it can take quite a while to warm up the bus. There larger unit can do it quicker if there is enough radiator.

It depends on the bus, but if you get into some cold weather and there is any amount of air turnover, you will likely find that even the larger unit could be too small while on the road.

For comparison, the main engine will pick up around a third of a million BTU while underway and a lot of that is made available through the original bus heat.

We have two furnaces AND our original bus heat, and that's the way that I want it. We do get into some cold weather every now and then.

For what it's worth.

Tom Caffrey

[prevost82]

I would agree between 40 to 60 BTU for a 40' bus
Ron

[JackConrad]

   We are presently installing a ProHeat system from parts we have been gathering (mostly off Ebay). We purchased a used ProHeat 45,000 BTU from Nimco, a new 65,000 BTU aux. heater near the drivers area, and an large (unknown BTU) heat exchanger to tie into the bius OEM cooling sytem. We are also adding 2 toe kick heaters (one in kitchen area and one in bathroom) as well as a small 7"x7" aux heater in the bay with the water tanks.
   The 65,000 btu is probably overkill, but we feel we can run the fan on low (or leave the fan off). We installed this heater near the driver's area under the sofa for a couple reasons. First, I think this area will be our biggest heat loss with poorly sealed holes in the floor around the steering column and brake linkage, as well as all that single pane glass in the windshield, drivers side window and door window and the entry door. The 2nd reason is that when driving, this is where we want most of the heat.
   Therer are several other variables, including how bus is insulated, number of windows (single or double pane), wind,and actual outside air temperatures.
Just our way, YMMV  Jack
   

[Jerry Liebler]

4106-123,
     I have a fairly similar bus with good, but not spray foam insulation, and can offer some data points.  My heating system is primarily an 18,000 BTU/h heat pump (ductless minisplit).  I also use 2 ea. 5000 BTU/h little electric fan heaters (electricity here in coal country is much cheaper than diesel fuel).  My back up heat is a 45,000 BTU/h Webasto system with 6 fan coil heat exchangers.  I keep my bus plugged in and heated all winter and hope the webasto never comes into use, it's thermostats are set at 45 degrees.  Right now the outside temperature is 30 and only the heat pump is running, but it's running continuously and the bus is at 64 degrees.  I have the thermostats on the 'resistance' heaters set to come on at 60.  Anyway the heatpump's ability to maintain a 34 degree diferential with 18,000 BTU/h suggests that the 45,000 BTU/h Websto can, by itself, heat the bus to 70 when its -15 outside.
Regards
Jerry 4107 1120