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Author Topic: Heat & AC Choice and Why?  (Read 6448 times)
Orange Blossom Special II
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73' MC-8 8V71/HT740 Southwest Florida

« on: February 01, 2008, 07:39:30 AM »

OK, I am working on another project for the magazine. Here is the Question:  What Did You Use For Your Heat & AC and Why?

  I will start with my answer. We used a basement AC because there is less fan noise and a smoother roofline. Our original plan for heat was a compass & thermometer (When the thermometer said 50 degrees, we would look at the compass and head south) This was supplemented by a small electric "cube" heater and an electric toe kick unit. We recently installed a ProHeat diesel fired boiler since we now occasionally spending time in cooler temperatures. After talking too several fellow busnuts with diesel fired boiler and some with LP furnaces, we felt the diesel fired boiler was a better choice and an easier installation is our already finished interior. (Easier to run length of 3/4' hose than a 4" duct)
  Remember, there are no wrong answers, everyone's situation is different and what works for you may not work for someone else. I am just interested in what works for you.  Jack

Growing Older Is Mandatory, Growing Up Is Optional
Arcadia, Florida, When we are home
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1995 Prevost H3-41, series 60, B500 Allison

« Reply #1 on: February 01, 2008, 08:56:25 AM »

Heat - Diesel fired heater and toe kicks.  I used because
1. The bus came with an Espar 40k BTU aux heater that could be modified for my uses
2. Many satisfied people with this system, purported to be "the Best"
3. It was a way to heat my domestic hot water too.
4. Single fuel system
5. Space efficient

AC choice - 3 Roof airs
1. Easy to install and service
2. My roofline and awnings hide them from the ground
3. I didn't feel I had the technical knowledge to install splits or basement air.
4. Low profile are not higher than other things on the roof
5. I kept bay space for toys
6. noisier than I had anticipated or hoped

ps I kept bus heat and air and am very pleased with that decision.

Jim Stewart
El Cajon, Ca.  (San Diego area)

Travel is more than the seeing of sights, it is a change that goes on, deep  and permanent, in the ideas of living.
Nick Badame Refrig/ACC
1989, MCI 102C3, 8V92T, HT740, 06' conversion FMCA# F-27317-S "Wife- 1969 Italian/German Style"
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Nick & Michelle Badame

« Reply #2 on: February 01, 2008, 10:05:56 AM »

Hi Jack,

HVAC- I choose 2 stacked 15,000 btu Basement Heat Pumps ducted to overhead outlets. Why? Whisper Quiet System, No Worts on the Roof, and it's

a system that is designed for Over the Road use.

Redundent Heating to the Heat Pumps- I have a Proheat X-45 piped to a Hydronic Coil in the return air of the Heat Pumps. Why? because Heat Pumps

loose their heating ability below 35 deg's, Extra capacity if I want, I can heat the bus on diesel or electric if I choose, and have a choice weather I'm in

a park with paid electric, or at my home where I pay for electric.

OTR HVAC- Factory system. Why? Because it does the job in any climate.

What would I do differently next time? Install a loop of radiant heat under my Marble Kit and Bath Floors. "coooold feet in the winter" Shocked

Hope this helps
« Last Edit: February 01, 2008, 11:37:36 AM by Nick Badame Refrig. Co. » Logged

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« Reply #3 on: February 01, 2008, 04:22:53 PM »

Basement air because I didn't like the looks of rooftop air units and wanted less noise.

Aquahot diesel fired heating system with hydronic radiant heat installed in the floor and walls. Why? Because everyone
said it wouldn't work in a bus Smiley


Craig Shepard
Located in Minnesquito

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« Reply #4 on: February 01, 2008, 07:20:30 PM »

Since I have a transit, my bus needs are a little bit different.  First I got rid of the under floor central heating system (no A/C since it was from Portland), pressure tested the big heating heat exchanger and then mounted it in the hallway on the floor with two 14" 12v radiator fans to push the air into the hallway.  It is so powerful, when I hear it come on from the driver's seat, I can count to 10 and feel heat.  Kept the original front defroster system.
For parked heat I have a 35,000btu propane furnace mounted next to my stove (stove and furnace are the only propane items on the bus with the tank directly chassis mounted below for the shortest gas lines possible [don't like propane]).  Also have heating strips in the three roof airs and a electric wall heater in the bathroom. Very pleased with the system-will probably use the same on my next RV.

My only A/C is three Coleman 13,500btu roof airs.  Driving in 107 degree weather, only ran the front two and was comfortable.  A 12v dash mounted fan blowing right on me made a big difference.  They work well, but would use Duotherm next time since the Coleman's only have a two speed fan-like medium and high- and the Duotherm has the extra third speed for a quiet low speed.  I think also next time I would eliminate the third A/C over the bed in place for a 14,000btu split CruiseAir that would be 7,000btu in the bedroom and 7,000btu in the living room for after dark use and quiet night time use.

After pricing the AquaHot and the fact that I live in Los Angeles, I felt I didn't need the tremendous heating capability of 80,000btu of the AquaHot (plus having 2" of sprayed on insulation really helps).  I have been using the bus on the average of 5 trips a year since it was done in 2000 and have yet to have any trouble with any of my appliances.  The only thing I have had to overhaul is the ball valve on the toilet-otherwise every thing has been 100% reliable.  I know those with AquaHots can't say that.  Good Luck, TomC

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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1981 MC9 8V71, HT 740

« Reply #5 on: February 01, 2008, 08:50:50 PM »

Two Coleman Roof airs, I belive they are 13500 BTU,
have heat strips that dont seem to do much and
are in the emergency hatch holes,  would rather have the hatches
two speed fans are loud but was glad to have them last summer at  the beach

Why? because they were there when i bought it.

Also have have two electric radiaters to plug in.

just bought a pro heat to try to set up and use for hot water.
« Last Edit: February 15, 2008, 03:44:59 AM by NewbeeMC9 » Logged

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« Reply #6 on: February 01, 2008, 09:18:07 PM »

First I was new to this whole bus conversion thing, and unfortunately I did not know about this site, until after i converted.

I like the basement air idea. we are in the fiber optic business and use the rooftops for our splicing trailers, in using the rooftops (now in fairness we use the cheapest ones and they are not ducted thru the roof) i knew that would be loud and I also knew that do a correct job for the south in summertime (100+) heat in a metal bus that I would need 5 tons of air = 5 rooftops and even thought a lot of the high dollar conversions go this route, and you would have automatic redundancy, even if one of 5 was down you most likely would still be pretty comfortable -- i still wanted to do the basement air ...

The old bus that I was converting (a mc7 mci) I noted that existing  system was designed at 7 tons, that the coils were over sized even for this rating, they have a system to distribute the refrigerant across the entire coils with expansions valves (by better distributing the refrigerant the system can except more heat and reduce the tendency to freeze up while operating at a lower temp) ... the old system was r12 so I converted the expansions valves to r22 (the old otr system was not working -- even thought the compressor was a rebuild the PO complained the otr would not keep up) added a 5 ton copland scroll compressor (I placed this unit in the condenser box) converted both the air handling fan and the condenser  fan to 240vac added the controls and plumbed in the compressor.  I had to change both expansion valves (on the main evaporator for the coach and the valve on the small evaporator for the drive air) ... I then ducted the air along both sides of the coach in the conversion and have my basement air -- i used the old floor depression as a return -- the unit gets it return air from the front of the bus and return under the bed in back -- i kept the old filter system in the bus and added a modern filter past the original filter (wire mesh)

works great -- but you have to run the genset anytime you want heat or air -- for the heat I did not remove the heater core for the main coach or the driver -- but i have not needed them - i added a small heat strip in the system and main thermostat uses that for heat control.  I have contemplated a 24volt - 240vac inverter in that way you could heat or circulate air with out have the genset on line -- but i do not mind running genset all the time -- when you are burning ~ 10 gals an hour with the coach on the road -- was is another 1/2 gal to make everything simple  -- i run most everything on 120 vac

feel free to contact me if you have additional questions --

The drawbacks are that on the exterior when the condenser motor comes in it is pretty loud on the exterior -- on the next bus I will do a varable drive for this motor and control the speed of this fan based on the heat pressue and exterior temp ... and do a variable on the interior air handling as well

hope this helps.

1972 MC7

Parker Systems, LLC
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« Reply #7 on: February 02, 2008, 05:55:03 AM »

Two ducted 13,500btu roof airs. Ducted because I can put the air where I want it. We have vents over the front seats that keep us cool in the hotest weather. Usually run just the front air off the inverter while on the road.We run the front air at night, to keep down the noise in the bed room.I put a butterfly valve in the duct to isolate front and rear, but usually just keave it open.
 Hydronic heat fired by a Pro-Heat with baseboards and three kick heaters. Also provides heat for domestic hot water and engine pre-heat.
 My first choise would have been a system like Nick's, but there wasn't room in my RTS. All in all both systems work great.
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« Reply #8 on: February 02, 2008, 07:09:30 AM »

I used a mini split heat pump and supliment with electric heaters. electricity is cheaper than fuel and I rarely boon dock. Jerry

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« Reply #9 on: February 02, 2008, 07:15:30 AM »

don;t forget to mention the Diesel fired Forced hot air units by webasto and espar.

best bang for the buck IMHO, size of a shoebox and one will keep a 35 foot coach toasty down to just below freezing while using little fuel, no noticiable electric and will suck the humidity oout of the air.

no plumbing to worry about in your layout. or leaks to be concerned with.  no electric pumps to have to run, no fans at each in coach unit to power.

available in 12 and 24v

« Reply #10 on: February 02, 2008, 08:06:36 AM »

Jack, for air I choose the Cruiseair split system for space and to keep the top of my bus clean 2 units are installed in the spare tire bay with one evaporator in the drivers and living room area another evaporator in the kitchen with a vent to the bath the other unit is installed at the back with two small evaporators for the bedroom. I love the variable speed fans 0 to high for the night time sleep.I would like to upgrade to touch pads controls but the price Nick said it would cost I will be turning knobs for a while

For heating i choose the Primus system over the diesel fired systems because of the smell and noise, it has 2 propane boilers and 1 electric boiler to take advantage of the electric when parked.I have 76 lf of radiant heat with 3 kick heaters on this system (which I never use)my bays are heated, the system is tied into my defroster in the drivers area to keep the windshield frost free when parked with a thermostat control for a kick heater in the drivers area if needed plus the Primus under floor heat.The only draw back is having two fuel sources but it uses so little propane with todays diesel prices I am glad to have it 
« Last Edit: February 02, 2008, 04:56:46 PM by luvrbus » Logged
1990 Thomas "Hormone Derange" Gunnison, Colorado
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1990 Thomas Transitliner, 8.3 Cummins/Allison Auto


« Reply #11 on: February 02, 2008, 08:34:26 AM »

A/C: one rooftop 15KBTU Coleman. It's usually cool here and we don't need alot of A/C. We have lots of windows for fresh air cooling and one fantastic fan.
Heat: Now this is where I went a little overboard, it gets chilly here. Thomas was a ski area bus, so it came with lots of heat. Big bus heat up front and two dual fan underseat units. Kept all of that, one underseat unit under the RF couch with toe kick height vent and one under the rear bed. System also has Espar boiler. Works great for stationary heat, pre-heating the engine for cold starts and heating domestic water thru heat exchange coil in water heater. Added 35K BTU propane heat in center of the bus for that extra measure. Also no diesel exhaust if I'm around other folks. Should have ducted it front and rear, but did install it so it gets make up air from the front and blows out in the middle. 110 ac ceramic block to blow in the bath for extra comfort.
Doug Engel, Gunison, CO

"If people don't stare and point as you drive by, keep working."
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« Reply #12 on: February 02, 2008, 08:50:18 AM »

We have two Duo-therm roof airs, a Suburban 35K furnace and an Olympian catalytic auxiliary heater because thats what the PO had in the bus when we bought it.  We boon dock a lot so we can run the heat off the batteries. I don't know what I would put in if I did the coach myself but I would lean toward radiant in the floor. I would definitely leave OTR heat & air in the bus. Unfortunately, ours was already removed before we bought it.
« Last Edit: February 03, 2008, 06:04:29 AM by oldmansax » Logged
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« Reply #13 on: February 02, 2008, 05:58:18 PM »

I choose rooftops for my A/C as I couldn't afford the the bay space for basement air nor do I really have space in my design for the ductwork.

I originally planned on a propane furnace, but I couldn't come up with a good place to mount the furnace and get the exhaust to not hit something.  I also didn't have much room for heat ductwork.  I will be installing a Proheat system for heat and hot water.

My OTR heat and A/C is gone.  The A/C didn't work and it required more work than I wanted to spend money on.  The heat was supplied by baseboard radiators and they would have been in the way so I removed them.  The A/C ductwork was part of the overhead luggage racks so I would have had to come up with new ductwork if I had kept the A/C.  The driver's heat and defrost still work.  The defrost will actually warm the front living area on a 40 to 50 degree day.

Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN

« Reply #14 on: February 03, 2008, 03:07:09 AM »


How did you run your exhaust on you Proheat? Is it OK to run an elbow just under the bay floor and out to the side? Could not quite tell from your Picture. I'm worried about the pipe being too low and getting knocked off or bent. I was considering putting my Proheat in the second bay, passenger side in front of our hot water heater. That's about the only room I have left.


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