THINK!! before removing your factory A/C!

[Polarweasel]

I kept forgetting to sticky this. Fixed now.

[cadillackid]

Originally Posted by Polarweasel

I kept forgetting to sticky this. Fixed now.

Super!!!!

Oh and for those still on the fence about AC..

My big trip in August had me going from Ohio to the Carolinas and Florida .. both coasts and central Florida. And down to key west.. up info Alabama. Georgia and such...

This day it was nearly 98 out and dewpoint close to 80... I was enjoying the views and the cold air !! i have this AC system dialed in. My whole firewall is dynamatted and insulated.. and this bus has 70,000 btu system and could still use a second unit at the rear to keep the whole bus cool in this type weather

[cadillackid]

Oh yeah and most important reason to have dashboard Air Conditioning..

[Doktari]

The factory 12 volt mini split AC system is free for the taking from the shuttle bus I bought a few days ago. I don’t know what condition it is in. It probably needs a charge and the fan makes noise. Needs oil at the minimum. The bus came for Missouri originally. May not have been used much if at all here in the Puget Sound. The inside unit is above the rear door and will be in my way. The outside unit is under the side of the bus and I might place a tank there.

[wrenchtech]

Thanks for this discussion. It is really timely for a guy who is trying to buy his first bus. I almost bought a bus where the guy had ripped out all the air conditioning and was touting the benefits of his 12,000 BTU rooftop RV Air-con. And then I was looking at big old Thomas HDX models with no AC at all and marveling at how reasonably they were priced. Now I see why the southwestern buses command higher prices, not only are they rust free they have the industrial duty air conditioning

[wrenchtech]

I am on the steep part of the learning curve with regard to these buses. This discussion about the industrial-strength air-conditioning required to cool the bus as you go down the road leaves me wondering, If you have such a system in your bus, what are you going to use to cool the interior of the bus when you are at not moving, for instance at a campground. Are you going to idle your big 8.3 L Cummins the whole day and night, or are you going to have to have a completely separate air-conditioning system for use when the bus is stationary?

[PatrickBaptist]

Originally Posted by wrenchtech

I am on the steep part of the learning curve with regard to these buses. This discussion about the industrial-strength air-conditioning required to cool the bus as you go down the road leaves me wondering, If you have such a system and your bus, what are you going to use to cool the interior of the boss when you are at not moving, for instance at the campground. Are you going to idle your big 8.3 L Cummins the whole day and night, or are you going to have to have a completely separate air-conditioning system for use when the bus is stationary?

That was my thought when choosing a bus, I went to a large salvage yard that had 70 of them, I chose a bus with a better trans over the ones with the ACs in them (they had AT545s and I won't have one). I went with the lowest mileage bus with the Allison MD3060. Wish I could have gotten that 8.3 but they didn't have any RE buses with them and that was the other must have for my plan.
I'm using 2x 15kBTU roof air units from a 84 year RV I scrapped out and they have done a fine job upto 98F and humidity in the 90s. When driving (which I haven't needed AC last time I drove it) I would just close off the rear half from the front and run the front AC which I'd think would be fine enough. I also don't think I'd like the extra pump and plumbing on the engine when it comes time to having problems on the road, I always plan for it to happen and want dealing with it to be as easy as possible to deal with, another reason for the RE, I can climb inside and get to everything easy, especially after I do the fuel bowl delete on my 7.3.

[o1marc]

Originally Posted by wrenchtech

I am on the steep part of the learning curve with regard to these buses. This discussion about the industrial-strength air-conditioning required to cool the bus as you go down the road leaves me wondering, If you have such a system in your bus, what are you going to use to cool the interior of the bus when you are at not moving, for instance at a campground. Are you going to idle your big 8.3 L Cummins the whole day and night, or are you going to have to have a completely separate air-conditioning system for use when the bus is stationary?

There in lies the dilemma. Have to have 2 systems or compromise. The factory units work great, but take up massive amounts of head banging room and are useless when not running. On the other hand mini-splits work fine for stationary use, but are worthless going down the road.

[wrenchtech]

I think I am still reeling from learning that it takes 120,000 BTUs to cool a bus as constructed by the manufacturer. It makes sense though, sheet metal and glass don’t offer much insulation. A bus is really a small solar oven. The building codes for residential construction now mandate at least R30 insulation for a ceiling and R13 for walls in even the warmest climate zones. That could be achieved with spray foam applied at roughly four inches in the ceiling and two inches at floor and walls. In the upper Midwest where I live you would need more like 7” and 3”. Removing as many windows as possible and installing a better door would go a long way to improving energy efficiency. Properly done, I have to believe that the cooling requirements could be reduced to a fraction of 120,000 BTUs, perhaps to the point where some version of an electrically powered mini-split could do the job, drawing its power from an engine mounted alternator, a solar setup, an auxiliary power unit, or shore power. So I guess it all depends on your purpose and desires. If your bus is mainly a means of transportation you stick with the factory air and if it’s more of a living space, you go high tech on insulation and HVAC. Of course, you are not going to get that kind of insulation in a standard height bus and still have A reasonable amount of headroom unless you’re very short, so it looks like that solution is left to those who are willing to raise the roof. No easy choices here.

I’m sure this is all been covered somewhere else in this form, but I am new and wanted to get that off my chest. Thanks for bearing with me

[o1marc]

Originally Posted by wrenchtech

I think I am still reeling from learning that it takes 120,000 BTUs to cool a bus as constructed by the manufacturer. It makes sense though, sheet metal and glass don’t offer much insulation. A bus is really a small solar oven. The building codes for residential construction now mandate at least R30 insulation for a ceiling and R13 for walls in even the warmest climate zones. That could be achieved with spray foam applied at roughly four inches in the ceiling and two inches at floor and walls. In the upper Midwest where I live you would need more like 7” and 3”. Removing as many windows as possible and installing a better door would go a long way to improving energy efficiency. Properly done, I have to believe that the cooling requirements could be reduced to a fraction of 120,000 BTUs, perhaps to the point where some version of an electrically powered mini-split could do the job, drawing its power from an engine mounted alternator, a solar setup, an auxiliary power unit, or shore power. So I guess it all depends on your purpose and desires. If your bus is mainly a means of transportation you stick with the factory air and if it’s more of a living space, you go high tech on insulation and HVAC. Of course, you are not going to get that kind of insulation in a standard height bus and still have A reasonable amount of headroom unless you’re very short, so it looks like that solution is left to those who are willing to raise the roof. No easy choices here.

I’m sure this is all been covered somewhere else in this form, but I am new and wanted to get that off my chest. Thanks for bearing with me

That massive system was only designed to drop the temps 20* from ambient.

[cadillackid]

You definitely need less cooling in an insulated bus but as some have found a couple mini splits don’t cool it on the highway in hot weather..

Most commercially built motor homes have AC for stationary use and AC for driving .. some of them have dashboard and single small evap rear and then count on you running generator and rooftop units while driving as needed.

Do you need 120k btu to cool an insulated and less windows converted bus? The answer is a good likely no but you very well may need 60

Insulation sin great but you are driving into hot wind at 65 sitting in an uncovered windshield with a big Diesel engine making heatceother in front of or behind you..
When parked you don’t have that 65 mph wind and you can curtain that windshield and there’s no diesel engine heat..
there’s no reason you can’t cistomize your AC and move your units around or even ditch the factory evap and roll something of your own. Sized properly but engine driven ... I built my own Inc the dev bus I have a custom dashboard unit..
You can do your AC however you want.. and maybe you don’t mind roasting or aren’t driving in the heat. I personally end up going laces I don’t always plan to be my original choice wasn’t to tour the south in the first week of August but it happened and I’m glad for the AC cause it was darn hot...

I haven’t been in a bus yet that I didn’t see some sort of dead space or ability to incorporate a hanging unit into a conversion.. are they ugly ? As stock yeah but they don’t have to be.. or you can use parts of the system and make your own ..

The cheapest and easiest is to keep the existing the way they are..
Christopher

[PatrickBaptist]

Originally Posted by o1marc

There in lies the dilemma. Have to have 2 systems or compromise. The factory units work great, but take up massive amounts of head banging room and are useless when not running. On the other hand mini-splits work fine for stationary use, but are worthless going down the road.

Yeah I wanted to do the mini split setup but I read what you said as well and not sure what I want to do about it, the roof air units in mine are from 1984 and though they work great, the motor in the front is about done for (bearings giving up have to grease it up every so often) so I will have to replace them next summer. Shocked they still work, used em all last year too, when I first turned them on they were locked up but responded well to some prayer and lithium grease.
I want something more energy efficient, we are doing the bus living to save money to buy property outright and build our home on it to do the homestead thing. Big reason I care about power usage is we are going to generate our own power and not fool with the electric company, I have a 4bt I am building a genset out of just need a gen head to finish the build, wanting to find something around 30-50kw range. I refine my own waste oil(ATF/brake fluid/motor oil/heating oil/rail road diesel/hydraulic fluid/power steering fluid anything but veggie oil) for fuel so after the initial investment the power shouldn't cost too much since the oil is free for the taking.
In my F350 I'd run 80% waste to 20% diesel, no smoke unless I stomped the go pedal, in winter I would do around 60-70% waste oil.
So I'm betting per kwh I can make electricity cheaper than I can buy it.
I'm not going the solar route, I need dependability and some days I use a welder. I do plan to do a battery bank on down the road so the gen doesn't run full time, but I don't want to have to rely on what the weather has in store for me. Same plan with the bus itself, I do have a 15kw gen head just waiting to find a engine for it and that will go in the bus setup.
And yeah run the bus on waste oil too, but not until I do the fuel bowl delete and install better filtration on it.
Anyways sorry for the long blabbery.

[Doktari]

For those on a small AC budget: I read about and watched a video about a RV solar installer who spent a year going over the specs of small window AC units. He wanted to figure out a affordable system for folks on a $139 budget and a system that could run on his solar. It’s a different strategy than the big factory system in a bus. The GE 5000 btu unit was the best he could find for the money ($139). The strategy is to let the RV cool down at night then try and keep it cool using solar energy all day. If allowed to get hot inside it wont be able to cool it down unless a second unit is purchased. One worked fairly well in his 27’ travel trailer but he did get a second unit just in case. Still a relatively small investment.
He has around 1200 watts of solar panels. 750 watts on the trailer and a giant 435 watt panel on his truck. After the brief initial power surge he says these units were consuming around 400 watts running. And in eco mode they would not consume as much power because they stop some of the time.
The giant factory AC systems in buses are to cool down passengers quickly by blasting out cold air. As I’m up North in the Summer I’m only going with the small 5000 btu units and mostly solar. Down South in high temperatures would be a different story. I think the temperature was averaging about 20 degrees cooler inside his trailer with one unit unless it gets extreme hot outside. 20 degrees difference on average was also my experience in my Motorhome using solar powered 9000 btu mini split AC also but it’s entire roof is shaded by solar panels and there is 4” of foam insulation in the ceiling. These factors kept it from heating up as fast in the morning. Often I would not need to turn a fan on until 1:00 pm. But a unshaded metal bus roof can heat up fast as I’m sure you’re aware.
I Africa I saw Safari roofs on the Land Rovers. Simply a second layer of aluminum with a ventilated air gap. My friend was going to do this on his Greyhound bus but gave up for now as it’s a big job. Insulation under the second layer might be better than air.

[wrenchtech]

Originally Posted by cadillackid

You definitely need less cooling in an insulated bus but as some have found a couple mini splits don’t cool it on the highway in hot weather..

Most commercially built motor homes have AC for stationary use and AC for driving .. some of them have dashboard and single small evap rear and then count on you running generator and rooftop units while driving as needed.

Do you need 120k btu to cool an insulated and less windows converted bus? The answer is a good likely no but you very well may need 60

Insulation sin great but you are driving into hot wind at 65 sitting in an uncovered windshield with a big Diesel engine making heatceother in front of or behind you..
When parked you don’t have that 65 mph wind and you can curtain that windshield and there’s no diesel engine heat..
there’s no reason you can’t cistomize your AC and move your units around or even ditch the factory evap and roll something of your own. Sized properly but engine driven ... I built my own Inc the dev bus I have a custom dashboard unit..
You can do your AC however you want.. and maybe you don’t mind roasting or aren’t driving in the heat. I personally end up going laces I don’t always plan to be my original choice wasn’t to tour the south in the first week of August but it happened and I’m glad for the AC cause it was darn hot...

I haven’t been in a bus yet that I didn’t see some sort of dead space or ability to incorporate a hanging unit into a conversion.. are they ugly ? As stock yeah but they don’t have to be.. or you can use parts of the system and make your own ..

The cheapest and easiest is to keep the existing the way they are..
Christopher

I would like to get a pusher with an 8.3 Cummins, but most that I’m seeing come without air-conditioning. Right now I’m looking in places like eBay, Facebook marketplace, Craigslist, truck papers and some of the bus dealers that have websites I want to raise the roof and insulate like mad. So I think the evaporator side would be getting some modification anyway.

[PatrickBaptist]

Originally Posted by Doktari

For those on a small AC budget: I read about and watched a video about a RV solar installer who spent a year going over the specs of small window AC units. He wanted to figure out a affordable system for folks on a $139 budget and a system that could run on his solar. It’s a different strategy than the big factory system in a bus. The GE 5000 btu unit was the best he could find for the money ($139). The strategy is to let the RV cool down at night then try and keep it cool using solar energy all day. If allowed to get hot inside it wont be able to cool it down unless a second unit is purchased. One worked fairly well in his 27’ travel trailer but he did get a second unit just in case. Still a relatively small investment.
He has around 1200 watts of solar panels. 750 watts on the trailer and a giant 435 watt panel on his truck. After the brief initial power surge he says these units were consuming around 400 watts running. And in eco mode they would not consume as much power because they stop some of the time.
The giant factory AC systems in buses are to cool down passengers quickly by blasting out cold air. As I’m up North in the Summer I’m only going with the small 5000 btu units and mostly solar. Down South in high temperatures would be a different story. I think the temperature was averaging about 20 degrees cooler inside his trailer with one unit unless it gets extreme hot outside. 20 degrees difference on average was also my experience in my Motorhome using solar powered 9000 btu mini split AC also but it’s entire roof is shaded by solar panels and there is 4” of foam insulation in the ceiling. These factors kept it from heating up as fast in the morning. Often I would not need to turn a fan on until 1:00 pm. But a unshaded metal bus roof can heat up fast as I’m sure you’re aware.
I Africa I saw Safari roofs on the Land Rovers. Simply a second layer of aluminum with a ventilated air gap. My friend was going to do this on his Greyhound bus but gave up for now as it’s a big job. Insulation under the second layer might be better than air.

Hey man, don't take this the wrong way, I couldn't handle the look of a window ac hanging out of my bus and I'm a redneck. Some RV parks are picky especially with buses, the window AC could really cause you to be turned away. We were only let in one park just because our bus looked normal and wasn't older, if we would have had a AC hanging out the window no doubt that lady would have turned us away. Just something to keep in mind for those that goto RV parks.
We have been turned away from one park, and what was really retarded is the year before we camped there for 2 days in a 1984 motorhome that wasn't a looker and they turned me away in a 20 year newer bus, dude told me to go get my old RV and they would let us stay. I laughed at him an said "there must really be something wrong with your thought process".

[Doktari]

Originally Posted by PatrickBaptist

Hey man, don't take this the wrong way, I couldn't handle the look of a window ac hanging out of my bus and I'm a redneck. Some RV parks are picky especially with buses, the window AC could really cause you to be turned away. We were only let in one park just because our bus looked normal and wasn't older, if we would have had a AC hanging out the window no doubt that lady would have turned us away. Just something to keep in mind for those that goto RV parks.
We have been turned away from one park, and what was really retarded is the year before we camped there for 2 days in a 1984 motorhome that wasn't a looker and they turned me away in a 20 year newer bus, dude told me to go get my old RV and they would let us stay. I laughed at him an said "there must really be something wrong with your thought process".

Good point. Glad you mentioned the appearance of the window mount AC. The solar guy who demonstrated the AC unit built a clever sliding mount so it’s inside when traveling. And it doesn’t stick out very far when in use. But, yeah, being turned away from a RV park is a concern . Do they really do that? Reminds me of HOA, homeowners association, things I avoid like the plague.

[cadillackid]

remember this is about Driving A/C.. there are all kinds of creativer ways to A/C with a low nuymber of BTU's while being parked.. from double-top roofs to insulation to sub-cooling in the AM etc..


Doktari is right.. busses use large systems to cool quickly on the road in hot weather.. and you need some of that when you drive also, for mentioned reasons,. a window unit isnt gonna cool your bus while driving.. though parked in the shade it might..



however like mentioned i dont think you need 120,000 BTU to cool a converted and well insulated bus driving down the road.. half that will likely do.. esp if you relocate your units to the front where they cool the main passenger compartment..



personally if I were doing a conversion I would spend the $$$ to invest in a front bulkhead evaporator that ius mostly concealed inside that useless space above the windshield.. the vents blow out and down. with most of its cooling up front..

if you have a big alternator or a built-in generator its not out of the question to run your Minisplit or camper A/C if there is someone in the back of your rig needing to stay cool..



I know alot seem to be on shoe-string budgets.. if thats the case and your bus comes with factory A/C you have to make the decision between comfort or a little "ugliness" inside your rig..



these units CAN be altered to some extent.. the only hard-fast rules are that you size the condensors and evaporators and compressors and hoses as a set... but altering cabinetry, positions, etc are pretty flexible as long as they have good airflow...



airflow with A/C is paramount.. cool air moving will make occupants feel cooler..



my DEV bus is perfect example... even with it needing another 40-50k BTU to properly cool the inside, i was nice N cool in my driver seat because I have 6 vents pushing 40-some degree air .. get up from the driver seat and im like "wow its warm in here still.."...

-Christopher

[PatrickBaptist]

Originally Posted by Doktari

Good point. Glad you mentioned the appearance of the window mount AC. The solar guy who demonstrated the AC unit built a clever sliding mount so it’s inside when traveling. And it doesn’t stick out very far when in use. But, yeah, being turned away from a RV park is a concern . Do they really do that? Reminds me of HOA, homeowners association, things I avoid like the plague.

Hey buddy, oh yeah there are lots of picky parks. I sure was turned away for having a "school bus", even though the owner said ok on the phone, the host was another matter so after driving there we had to pull right back out.
Another barely let me in just because she thought mine looked better than the other campers in her park.
The ACs being pulled in when traveling, well then that means no AC while driving...
5k BTU sure isn't alot either, I use 2 15kBTU roof tops and they work pretty good but I sure wouldn't want less, so that would mean it would take 6 of those window units... Well then again my bus is just shy of 40', of course a smaller bus wouldn't require as much.

[o1marc]

I keep a small window unit stored in the "garage'. It slides right in a window opening and does a good job. Remove it when driving.

[musigenesis]

Originally Posted by cadillackid

Oh yeah and most important reason to have dashboard Air Conditioning..

Attachment 37255

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