| Author |
Message |
Nelson Thomas (205.188.209.8)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 06, 2004 - 10:34 pm: | |
Does anyone have any experience with a 4104 or 06 conversion with hot spray foam insulation?
How well does it retain heat and A/C? Just trying to plan for the size of heat and air systems in the build out. Would a heater with a range of 5000-12000 B. T. U. s be adequate for cold weather or would it take a larger unit?
Nelson, Knoxville TN. |
James Maxwell (Jmaxwell) (66.81.47.165)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 1:06 am: | |
That size heating unit would probably keep u reasonably comfortable down to about 40, presuming the insulation you mention, reasonable window covering, and adequate air distribution of that heat. Go much below 40 and you're going to have to break out the Mukluks. |
h3jim (68.105.103.139)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 4:26 pm: | |
I'm told by Dick Wright that a moderately foamed 40 ft bus, using webasto type hot water heat that 40,000 BTU is a good number to use for almost any circumstance. if thats true, Jim M's comment seems right on. |
Tom Caffrey (Pvcces) (65.74.64.127)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 10:19 pm: | |
Nelson, the biggest problem with sizing the heat on the small side is that it will take a lot time to get comfortable if your coach ever does get chilled inside.
And if you're chilly or cold, it's easy for your patience to run out. With 40,000 btu, it will warm up quickly enough that this should not happen.
Good luck!
Tom Caffrey PD4106-2576
Suncatcher |
Rodger in WA (64.70.24.209)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 12:01 pm: | |
Dick Wright's calculations are right on but keep in mind that heat and cooling capacity requirements in a well insulated coach will vary greatly with your coach's total window area and type. Windows are nearly as important as insulation and HVAC capacities and should be a significant factor in your HVAC calculations.
Besides reducing heat loss or gain, thermopanes greatly reduce condensation on the windows.
Here's a case in point: A friend's late model professionally converted 40' Prevost has tall single pane curved OEM windows. His window treatments don't contribute much insulation. Despite good insulation a 40,000 plus BTU heating system and three roof air units, he complains that he can't keep his coach interior comfortable in temps cold or hot weather.
Our coach is a 1976 35' Prevost with about 3/4" sprayed foam in sidewalls and roof. It has tinted thermopanes, except for the windshield. It has pleated shades on the side windows. The headliner is naugehyde with about 1" of airspace between h'liner and the foam. Pleated shades contribute greatly for window insulation but the windshield has privacy blinds which are ineffective as insulation. I cover the w/s with a sheet of foil faced bubble wrap in cold and hot weather.
A 3 zone Webasto hot water/forced air heating system, two roof air units with heat strips and two roof vent/fans easily keep our coach very comfortable in the most extreme temperatures we've experienced. These include 15 deg F with a 30 mph wind and 110 deg w/high humidity. In the coldest weather we've experienced, the Webasto system ran about half the time, keeping the coach at 70 deg.
When parked in temps down to 40 deg. with outside elec. power available, I usually run just the roof air heat strips or a small elec. ceramic heater, which is quieter. Except when underway, the system I use the least is the Webasto. In 15 deg weather can keep one or both roof vents cracked open to preclude condensation.
Awnings over all side windows help greatly in hot weather and allow us to keep the windows open in warm rainy weather, rather than run the a/c units.
In my opinion, good insulation, tinted thermopane windows and awnings are just as important as HVAC capacities.
Additionally, for driving in hot weather, driver/buddy seat fans mounted at the outside corners of the windshield are a very worthwhile investment. In hot weather, lots of heat radiates through the windshield, especially when driving into the sun.
This is more than you aked for, so I apologize for this overly long dissertation.
Good luck with your project. |
TWO DOGS (67.209.132.203)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 14, 2004 - 11:18 pm: | |
I think generaly...a bus needs min. of 40,000 heat & 36,ooo to 48,000 for cool...and think the more windows you eliminate the easier those systems will have to work... |
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