Converting a Grumman step van into a mobile showroom. HVAC and electric

I was looking for a long time to convert an RV into a mobile showroom but decided to convert a 14' Aluminum body step van for my salesman and clients.  I have a few questions. Hope someone can help or lead me to information.

1-We want to add a rooftop ac/heat unit to cool/heat the entire van. There is no insulation at all anywhere. In fact the roof has semi-clear fiberglass running down the middle to let in natural light. We can add 1" thick on the sidewalls in between ribs but the roof, back wall and doors and front section can not be insulated so it seems like a waste to only do 40% of the walls. Inside of cab is basically 6'-8"' wide, 6'-8"' tall, and 18' from back door to windshield. I have seen the Coleman Mach III unit 13,500 BTU online. I will want it to run while driving, also at customers house when they are sitting inside. We are in North New Jersey. Gets into the 90's in summer and below freezing in winter.

Will this be adequate?
Is it quiet?
Can it be run while driving to house so it is at comfortable temp when we arrive?

2-Need to add a generator to run this roof unit and some electronic equipment, Laptop, printer, router, camera charger and some low voltage lighting. We were planning on mounting it underneath the body to frame rails(plenty of room) and cut an access panel through side of body. BUT.............. I really need this to be as quiet as possible while we try to talk with customer and make a sale. Other than the roof HVAC unit, the electronics and low voltage lighting there is no other need for power.

Do they make a unit that we can tap right into the regular  gas tank?
Are there any "turn key" units that we can buy or do we need to build a custom sound deadened box?
How large of a unit do we need to buy?
Do they have models that need less maintenance than others? (It will be used a lot, I don't want the truck running when customers are inside)


3-The lighting I am getting already has an inverter to plug direct into wall outlet, same with electronics. I "assume" the HVAC is the same????

Do I need to buy an inverter?
Is there a separate fusebox we need to get?

Pics attached for reference.

A gas powered generator won't be real quiet.Not awful, but not quiet either. And yes it can be plumbed to the gas tank - standard practice is to place the second gas intake at the 1/4 tank level, so you can't suck the tank dry with the generator (very embarrassing!).

You don't need an inverter if you run the generator when needed, including while driving down the road.

I would add the insulation - that tin box is going to heat up badly in the sun. Insulate the metal part of the roof too. You might consider a pull shade of some kind for the translucent strip on the roof as well.

A standard roof top a/c is 13,000 or 15,000 btus, which should be enough for the volume of space you are cooling IF the rate of heat  gain is not too great. No way I can guess if that will be OK or not, but I would think that the sun would make an oven out of it quickly.

Do you really need the natural light inside the rig?  Since you're going to be running a generator anyway you have lots of power available for supplemental lighting.  A couple of fluorescent strips down the middle of where the translucent strip is now will provide almost as much light.  Or you can put in track lighting or whatever else may be appropriate for your displays.

If there's not enough room inside the box to let you add a couple of inches of insulation, you can put the foam sheeting above the existing roof.  Then put a new roof over the insulation.  EDPM rubber is used on many RVs and is also used for new roofs on buildings.  Maybe you could interest a building roofer in the job.

Checked it and there actually is fiberglass insulation running down both sides of the roof under the metal. I guess adding it where we can in the walls plus the roof 2/3 done would make a difference.

I want to keep the "feel" of the truck as wide open as possible that was the idea of leaving the light come through. I don't want customers to feel cramped or uncomfortable while inside. We are building all the display stuff pulled down from the roof by minimum of an inch so I guess if needed we could go back and fit in some insulation

Forgot.......will also be painting it fleet white. That is going to help.



Edit: You mention that gas generators are louder than others. The only reason I was thinking gas was because it would be easy to tie into existing tank. However my MAIN concern is noise. So if there are other options of fuel or manufacturers that would be quieter I am all ears.

Diesel generators are quieter for two reasons:

(1) They run at lower RPMS
(2) They are much more massive and absorb vibration much better

They also cost more and weigh more and would of course require an additional fuel tank.

A pair of Honda eu3000i would give you a lot of power and excellent noise levels.  Not real large either - can be set outside even.  Most any generator that uses an inverter to produce AC will be quieter than a direct AC generator. That's because they can vary the engine speed to match the load, while the direct AC type has to maintain high RPMs to keep the voltage & frequency right.

Gary, Correct me if I'm wrong, but I don't believe the EU3000i's can be paralleled like the 1000's and 2000's; then an Onan (or other) 7kW unit in a suitable enclosure might be a better choice. That would eliminate the necessity of separate circuits for the 2 gensets. Of course, that may not be all bad - he could wire the constant-use electrics to one genset circuit, and bring the second genset online only when necessary. Weight would be about the same with 2-3000i's @ 268lbs (dry) and one Onan 7000 @ 280lbs, but space would required would be much less with the Onan at33x22x16 (LWH) versus the Hondas at 26x19x22 for each of them. Consider also that the Hondas would have to be modified to run directly from the vehicle's gas tank, or be fed manually to keep their tanks full.

Karl,
Honda has a 50A parallel kit for the eu3000i, so pairing them is not an issue.  And running them separately might work in this case anyway - looks like one could power the a/c and another (which could maybe even be a 2000i) could power the rest of the needs.

Despite the physical drawbacks of two portable gensets vs one designed for mounting in a vehicle, I suggested this lash-up because QUIET was a major requirement. I had occasion to stand next to a running 3000i just the other day and carried on a conversation in a normal voice.  It was lightly loaded and just purred along.

Honda eu3000i

Thanks for setting things straight for me. I also like the idea of the locking 30A plug to prevent someone from accidentally 'pulling the plug' when in the middle of a customer meeting. I would suggest a small electric fuel pump rather than having to rely on gravity feed. Honda could probably tell him to proper pressure to set it at - probably no more than a couple pounds.