Questions regarding a custom A/C installation (pics)

66ChevyTailgater · 05-08-2005, 09:50 PM

We are going to attempt to install some A/C units in our bus. We do NOT want to look into overhead units as we may try to put in a roof deck sometime in the future. We have purchased two small A/C units and we want to mount them in a way that will look decent on the outside and will not impact our space on the inside. We have come up with the idea of mounting them in a pair over one of the wheel wells in the following manner:

My drawing sucks and it certainly isn't to scale, but we have measured and there is more than enough room over the wheel well for the two units - there is even enough room if we have to put a space in between them if there is a "rib" when we start cutting.

1. We plan on putting a rectangular box made of plywood directly on the wheel well with "legs" running the length of each side to keep it on there.

2. We plan on making the box taller than the A/C units themselves, so as to leave airflow room. This will be sealed as best as possible on the inside, but open to air on the outside.

3. We will bolt the units down to the box.

4. The units are 7500 btu's each, which should be adequate.

5. When we cut the outside of the bus, we will try and use the cutout as a "door," adding hinges to protect the units from the elements when they are not being used.

We have decided to go over the wheel well because the box will be about end table height (there are couches on either side of the wheel well) and it would be a great use of underutilized space. It will also be great for cupholders for those sitting on the couches.

So as you can expect, I have a TON of questions. I would appreciate if people would answer any and all that they feel qualified to answer. Thanks in advance!

1. What is the best way to cut the metal? What ways will work that might be cheaper?

2. Is there a rib or any other structural metal rod running where we are going to cut? Like I said above, we are planning on seeing one in the middle and we plan to mount them around it.

3. Do I really need the "airflow" space above each unit?

4. Can you think of a better way to mount them?

Once again, thanks in advance!

OK, after seeing the other buses, I've decided to include a second option for your review:

Again, sorry for the drawings, they're the best I could do. This option would allow me to utilize the windows, which are obviously already cut. Any ideas or suggestions?

Thanks!

trx · 05-09-2005, 08:41 AM

1. Cutting the metal probably depends on the tools you have available. On way is to make the initial cut with a 3" air cut off then use a reciprocating saw (Sawzall). It can be tricky to cut straight with a reciprocating saw if you are not careful. I'll let others speak up on other ways they have used.

2. Typically it's empty space. There's a verticle support between each window. The one over the wheel well probably doesn't do much since there's no floor to tie into.

3. You shouldn't if there are no vents there. You'll only need airflow where there are vents.

4. That's all personal preference. If you want a real challenge mount them under the bus and vent them up through the floor. You could even run ducting under the bus to have multiple floor vents. Of course it all depends on if the design of the air conditioner makes this feasible. It would involve a lot of creativity and work to pull it off. I don't think anyone has tried it before (maybe for good reason).

Chad

TravelingMan · 05-09-2005, 01:35 PM

Im not clear, are the units going to slide out when used? Just remember you can only be so wide on the highway not sure but think its 108 in.

Steve · 05-09-2005, 01:53 PM

My ac is somewhat similar to yours.

Here you can see I replaced the window with inlet and exhaust vents for the ac unit.

There is plenty of room for the inlet air around the sides of the unit.

After the exterior was in place ducts were constructed so that there was a vent in for cool air and out for hot. You be amazed at how well this works and how much hot air is blown on you if you stand under the vent.

TravelingMan · 05-09-2005, 02:18 PM

How well does one unit do at cooling the bus?

Steve · 05-09-2005, 02:24 PM

Quote:

Originally Posted by TravelingMan

How well does one unit do at cooling the bus?

I have insulation over all of the windows and coated the roof with CoolSeal. Even then the little airconditioner I have cannot cool the entire bus down on a really hot day. I have a door between the living and sleeping areas, with the door closed it does work very well.

I imagine if I had two of these or one twice as big it would cool the bus down very well. I think the one I have installed is a 7,200 BTU unit. What I did want to point out is not to be afraid to mount a conventional unit inside of your bus, with the right duct work the heat exchanger will work just fine. If you do find you need to move more air around it an electric automobile radiator fan can be easily adapted to give you enough extra circulation.

66ChevyTailgater · 05-09-2005, 07:00 PM

Quote:

Originally Posted by TravelingMan

Im not clear, are the units going to slide out when used? Just remember you can only be so wide on the highway not sure but think its 108 in.

No, we're planning on having a swinging door that we'll open when they're in use. I suppose vents would be another option, but we hadn't thought of that.

Thanks.

66ChevyTailgater · 05-09-2005, 07:05 PM

How easy was that setup to do. The reason I'm asking is that it seems like it would be MUCH easier to do than to start cutting metal!

Does the relatively small opening the vent provides hurt your coooling perfomance at all?

Thanks!

Steve · 05-10-2005, 12:12 PM

Well in the case of the small AC unit I have, I think the vents are sufficient in size. Just remember, the more and cooler the air you suck in the better your heat exchanger will work. The vents for the intake and exhaust on my insulation are insulated and sealed around the edges so there isn't any heat leakage.

dammitAndy · 05-10-2005, 12:30 PM

Nice Steve!

I was going to reply to this thread earlier but waited to see how it developed. I was originally going to mount a window AC unit on the outside of my bus too. But now that I see how you mounted it inside, its my new project

So there is plenty of airflow to the AC unit in that box you mounted it in??

trx · 05-10-2005, 01:07 PM

Steve, have you considered isolating the air conditioners side intake vents from the rear to prevent recirculating hot air back through the unit? It might improve efficiency. But what do I know, my bus is a/c-free (always run off batteries).

Chad

Steve · 05-10-2005, 01:46 PM

That is what I was trying to say. The Intake and Exhaust do NOT mix, each are seperatly vented, and insulated inbetween the two.

On my installation there is two louvered vents. One for exhaust and one for intake. On the rear of my ac unit a fan blows out hot air. The entire area behind where this fan sits, a foam vent is constructed from the rear of the ac unit to the exhaust vent. When the fan is running all of the air is blown directly out the vent, not allowed to recirculate back in the sides.

I will try to find a picture to post when I get home, although when I did it, it was hard to take pictures because of the small space above the unit and the roof.

trx · 05-10-2005, 02:04 PM

Quote:

Originally Posted by Steve

That is what I was trying to say. The Intake and Exhaust do NOT mix, each are seperatly vented, and insulated inbetween the two.

Sorry, didn't read close enough. The pictures don't really show how the vents are separated. Sounds like it should work pretty good how you have it setup.

Roasting8 · 05-10-2005, 02:15 PM

Hi Steve,

That's a great idea for the window air; not only does it look good it's also economical (cost of A/C unit as compared to a roof unit).

I only have one question for you: How do you take care of condensation? what I mean is; when you camp in a humid place, the unit drips from reaching dew point temp. Did you run a drain through the window drain or directly outside?

If you don't have a drain, you might consider it before you ruin the wood.

Thanks,

Roasting8

BTW, I'm also going to try your idea, I really think its great.

Steve · 05-10-2005, 02:33 PM

The model of AC unit I got said you are not supposed to drill a hole for a drain, you may want to look at that before you buy one. This one has a pan around the bottom of it and water that forms on the cool side gets collected and evaporated and blown out by the hot side. The only time I have had trouble with water is when I have been running the AC and then drive the bus right away. Then the water in the pan splashes out. Other than that, when the bus is sitting there isn't any problem with water.

lapeer20m · 05-10-2005, 02:42 PM

my favorite took for cutting straight lines in the side of the bus (if you're still planning to cut holes in yoru bus) is a metal abrasive blade for the standard circular saw. I find this is much easier to cut a straight line with this setup than using a sawz-all.

Wear safety glasses and ear protection. It's amazing how loud it gets!

Roasting8 · 05-10-2005, 04:39 PM

Hi Steve,

Thanks for the information about the A/C units. I was still used to the old type that had a drain hole in it. I also lived in Mississippi, that no matter how much tray you had, it still leaked water.

I might try to put another tray under the A/C unit and avoid the grief.

Thanks again for the info.

Roasting8

busone · 05-10-2005, 11:13 PM

This is simillar to what I am planning on doing. Many units have a drain plug at the rear of the unit. You can attach a tube to that or drill a hole in the bottom of the unit.

dammitAndy · 05-11-2005, 08:47 AM

Same here. It wouldn't be too hard to run a hose under the bus or out the side. Probably under though so you wouldnt get runs on the side. I love this idea. Soon as I get my electrical figured out, its on.

captainkf · 05-14-2005, 11:10 AM

There was a thread a month or so I started regarding under bus ac units. The plan was to install and vent into the bus. However after doing some figuring (never ending it seems) I have opted to not use under compartments to maintain clearance. So last week I installed my AC unit inside the bus in a similar fashion to steve's. However I went throught the side of the bus. There is about half an inch of the unit visible sticking out the side that vents. There was no concern on this model of condesation after having run it in the house for a few days strait.

I hadn't planned on installing the AC unit until I reached Halifax in the summer because I don't own one. There isn't much of a need for one here in Calgary Alberta. I gets warm but not hot enough for long enough. But when in BC a couple weeks ago I came across a unit in the dump while I happend to be there that somone had tossed. So I plugged it in and it worked great. woohoo!

I also was given an older model 2kw mcoulough (sp) generator. So now I have constructed two small platforms on the back of the bus. On which one is the new home of the generator. I built a box for it that has an intake vent and an exhaust vent. It's insulated with 2 inch blue sheet foam (also donated). The box is lifted off to start the generator. Very high tech. But it makes a huge difference in volume.

So the AC unit is locate in the middle of the bus in the kitchen area beside the propane furnace. It is resting on a 2 by 4 frame with another fresh water tank located underneith (sp) it. This was rescued from a van conversion at a local parts yard. Now I'm up to about 35 gallons of fresh water. I don't have a shower and don't plan on one until I redo the system next year so That should be ample water.

The AC unit has it's power cord run to the main power center. In theroy it could be run off the 1200 watt inverter but I haven't done this. It takes 950 watts to power it. I built an insulated box around the bottom and top. The sides are open and vent into interior compartments that it shares with the furnace so it is able to gather fresh air to push through the coils. So far so good. I will post photo's when able. -Richard

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