MLamontagne
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Hi. I'm a bit familiar with heat loss design for building's based on loss per square foot. Since a conversion van is an entirely differant animal, I was hopeing someone out there can give me some numbers (best case / worst case) that i can use for computeing what size a/c unit and heating unit i should be looking into.
I'm hopeing to get away (with a decent insulation job) a polar cub 9,000 BTU A/C (specs)
And a Webasto "Air Top" model 2000 ST B Specs heater (specs are listed toward the bottom of the pdf)
Right now, I'm kinda doing an inside-out approach before I purchase the van to be converted, so i can make the best choice as to what platform i'll be working off of. I'm looking to make this a 4-season camper.
Thanks in advance!
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My Roadtrek
Tucson, AZ.
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Joined: 03/20/2002
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No way a 9,000 BTU is good enough, you need something in the 13,000 BTU range. For example, under ideal conditions (a cool chassis), a Roadtrek, or PleasureWay's 13,000 BTU A/C will only cool the van down about 15 maybe 20 degrees max. With a hot chassis, from driving all day, you are probably looking more at 10 degrees.
Search the forums here, there are a lot of threads about this.
Visit My Roadtrek
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Bumpyroad
Virginia
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Joined: 12/01/2005
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what are dash ACs rated at? It would seem to me that the interior would already be somewhat cool while driving and the roof AC would merely have to maintain it.
bumpy
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Golden_HVAC
Fulltime, CA, USA
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Joined: 08/19/2003
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Hi,
If you want to spend all 4 seasons in Arizona, the design is a lot different that if you want to spend 4 seasons in Maine.
Sheet metal has a really poor R factor, but at least the wind does not get through. You might consider Reflex insulation for it's thin R-4 value, or if put in right, you can get R-6 per layer of insulation. So two layers of reflex might be plenty, and still only about 3/4" thick. (flatten the reflex and the insulation value drops off).
Home Depot sells yard sale signs that are made out of plastic, kinda looks like cardboard, expanded material that has tiny slots in the material, between the inner and outer covers. Well air conditioners are shipped with this same plastic covers, for protecting the coils from shipping damage. I put some on the roof of my work van, with reflex insulation above it, the plastic holds the reflex in place. I figure that the plastic must have a R value of about 1.0, while the Reflex is R-6. It made the inside of the van cooler, as it will sit out in the sun all day.
I have not seen the plastic material for sale in bulk form, but have seen many posters made from the same material. So people who print posters can prbably buy it in rolls hundreds of feet long. It would make a good interior panneling, if the material was white, or your desired color or pattern.
Please let us know what states you plan on camping in, especially in summer and winter. It makes sizing the air conditioner or heater system much easier.
Are you trying to stay away from propane? I hear that diesel furnaces can consume a lot of power. What I used for heat is a Olympic Catalytic Safety Heater. It is 6,000 Btu's and keeps my 30' Bounder motorhome toasty warm even when it is 32F outside. Below that, I run my 40,000 Btu furnace about 5-10 minutes per hour to circulate warm air around, and keep it close to 70.
I figure that I might as well be comfortable - most people keep their house close to 70, and probably use more propane or home heating oil, or electric that I would use in a year.
There are some yachting supply companies that sell diesel powered stoves, but they would typically be more expensive that going with a 20 gallon propane tank and conventional stove, or a portable set-up and 1 gallon portable tank.
Have fun camping!
Good Luck,
Fred.
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My Roadtrek
Tucson, AZ.
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It's not going to matter what state you are going to camp in, a 9,000 BTU unit is too small, it would just be a waste of money. You would be almost as well off with a good roof fan like a Fantastic fan, and one or two small wall, or table fans. Probably only a few degrees difference between this set up, and a 9,000 BTU A/C.
Anywhere that's over 100 degrees, even a 13,000 BTU is not going to make living in the camper very comfortable.
As Fred mentioned, there are several options for heating.
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CJBill
Rockville Md.
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Joined: 10/09/2005
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For example: I have a 05/06 Roadtrek Popular with a Dometic heat pump rated at 11,500 btu. We have been having some really warm weather here in Rockville MD and I wanted to test my generator which won't always carry the AC in hot conditions especially when driving or afterward.
So with the temp. at 98-99F I drove for an hour plus to a nearby Orchard then pulled in at home. The Chevy AC was running but not the motorhome AC. At home with the outside temp. at 99F I started the Gen. then AC which ran fine for an hour and 45 minutes. Because I wanted to know if the Gen. failed I lay down in the back and took a nap after closing off the front of the van with the bathroom door to try and keep myself cooler. When I stopped my test the temp. on the kitchen counter top just aft of the bathroom door was 87.5F. The Chevy van mirror told me the outside temp. was 100F. When I closed the bathroom door and went forward I noticed it was quite a bit warmer in that part of the van but I did not have a thermometer up there to record the difference.
So while 13000 btu would sure be nice the 11,500 btu I have seems adequate for me. However, DW did not nap with me and I am pretty sure she would have wanted to be cooler.
We have noted that the heat pump works good for heat down to the 40F where it is supposed to shut itself off. DW likes it much better than the furnace and will push the limit so hopefully it will take care of itself, as the manual says, because my authority is inversely proportional to how uncomfortable she is. So I think "we" are pleased we have a heat pump not just an AC.
Bill
CJ is the better half.
05/06 Roadtrek 190 Popular
Rockville MD
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My Roadtrek
Tucson, AZ.
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Bill, I believe yours is rated at 12,000 BTU, at least that's what the web site says.
One major factor is how long you drive the van, because if you drive it several hours at hwy speeds, the chassis gets hot, and it takes a long time for it to cool down. The wheel wells get so hot you can't even touch them. This make cooling the van a lot more difficult. There are things you can do like spraying water on the bottom of the chassis, opening the hood, and parking on grass, or dirt.
To the op, the older Roadtrek's had 8,000 BTU A/C's, and I think most of the owners will tell you that they don't help much.
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MLamontagne
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Thanks, Everyone!
Golden_hvac: Doh! I forgot one important detail: design tempature differance. I am more comfortable in colder weather then a am in hot, So i figure The hottest It will be (and me not moving on to cooler places) is between 80-95 degrees. On the cold side: Probabily between 0 and -15.
I like temps between 68-72 degrees inside.
MyRoadtrek and CJBill: Thanks for the tips and warning. I'm currently emailing the MFG of said unit, but it appears from a more in-depth look that its used mainly for Tractor-trailer units for cooling the berth (the small space in back)
BumpyRoad: Ive been doing some thinking and a bit of drawing. I'm mechanically inclined, and have more then one family member who works in the HVAC field. Your idea about the in-dash A/C parallels one of my ideas about moving the evaporator core (the part of the a/c that sits under the dash) to a floor mounted heater/AC unit that i can use to boost whatever a/c unit goes on the roof. I Know they sell specialized rubber hose for vehicle A/C units, and am looking into the feasibility of the above, possibility adding in the ability of what ive sen refered to as "swampy" (using ice to cool) cooling units. Finding a non-ac unit dash setup shouldn't be a prolbem if i stick with an older G20 series of van, which is my current pick.
Once again: THANK YOU to everyone!
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