Custom Mobile Office: How to Spec a Working Office in a Sprinter Van

What makes an office custom rather than a van with a desk

A custom mobile office is specified around the work being done in it, so the layout, the power budget, the acoustics and the connectivity are designed for that work rather than fitted from a catalogue.

That is the whole difference. A catalogue conversion asks what fits in the van. A custom mobile office asks what the work needs, then finds a van that carries it. The second question produces a vehicle people actually use.

This article is the specification guide. If you are still deciding whether to buy one at all, start with our guide to mobile office vans instead and come back here when you are ready to order.

Step 1: define the work before the van

Answer these four before you look at a single chassis. Every later decision falls out of them.

1. How many people work in it? One person needs a desk. Three people need three work positions, which is a completely different layout and a completely different electrical load.
2. Do clients sit in it? If yes, the cabin is a meeting room. Finish, privacy and acoustics move to the top of the list and seat count moves down.
3. Are calls confidential or recorded? This decides the acoustic specification and whether you need a full privacy divider between the cab and the rear cabin.
4. How many hours a day is it parked and running? This sizes the battery, the climate system and the insulation package. A van that runs two hours a day and a van that runs eight are different builds.

Write the four answers down before the first build meeting. Manufacturers who are worth working with will ask for them, and the ones who do not ask are the ones who will sell you a catalogue layout.

Step 2: choose the chassis

The chassis sets floor area, ceiling height and payload. Everything else fits inside those three numbers.

One work position fits the Sprinter 144. A desk plus 7 or 9 rear passengers needs a 170 Extended. The Super Single trades seat count for work surfaces and finish.

Step 3: lay out the interior

Three layouts cover almost every custom mobile office. Pick the one that matches step 1.

Single operator layout

One work position against one wall, facing the side of the van, with the opposite wall free for storage or a second seat. This gives the largest continuous work surface in the smallest vehicle, and it is the layout that works on a 144 chassis.

The trade is flexibility. A fixed desk against a wall is always there, which is ideal if the van is only ever an office and awkward if it also has to carry four people to dinner.

Two person facing layout

Two work positions facing each other across a centre aisle or a shared surface. This is the layout for a principal and an assistant, or for two people who need to talk while they work.

It needs the floor length of a 170 Extended. It also doubles the electrical load at a stroke, which is why step 4 comes after this one and not before.

Client meeting layout

The cabin as a meeting room: facing captain's chairs, a removable or fold-out table between them, and a full privacy divider to the cab.

First Class Customs fits a removable conference table to the VIP Shuttle, which is the clearest example of this layout in the range. For a smaller group, the Private Class build is laid out around four McLaren style captain's chairs with three fold-out desks, which converts between a meeting cabin and three working positions without any of the furniture leaving the vehicle.

Step 4: size the power system

This is the step that decides whether the vehicle works. Everything in the cabin is a load, and the loads add up faster than people expect.

Start by listing what will run at the same time, with a figure against each:

A laptop draws 45 to 100 W, a monitor 20 to 60 W, LED lighting 20 to 60 W and a router 10 to 25 W. Climate is several hundred watts and is the largest single load.

Three practical rules:

• Size for the real day, not the average day. The day that matters is the one where the climate runs for six hours and somebody prints.
• Charge from two sources. Shore power when parked at base, alternator charging when driving. Relying on one of them means a flat system on the day the other is unavailable.
• Document the system. Circuit by circuit, with the cable sizes. You will want it in year four, and a manufacturer who will not produce it is telling you something.

First Class Customs does its electrical work in house, and electrical systems are covered under the conversion warranty, which runs three years or 36,000 miles from the original purchase date.

Step 5: connectivity

Cellular, not fixed line. Beyond that, three decisions:

One carrier or two. Two. A single carrier is a single point of failure and coverage gaps are not predictable from a map. A router that fails over automatically between two carriers is the difference between a dropped call and a call that keeps going.

Internal or external antenna. External, on the roof. A van body is a metal box, and an internal antenna is working against the vehicle it is sitting in.

What to expect honestly. Parked in a populated area, a well specified van will hold a video call as reliably as an office. Moving, on a rural route, it will not, and no hardware fixes that. Plan the calls that matter for the parked part of the day.

Step 6: acoustics and climate

These two are specified together, because the same insulation package serves both.

An untreated van body is a drum. Road noise, panel resonance and tyre roar land squarely in the frequency range human speech occupies, which is why an untreated van is unusable for calls. A full insulation package treats the floor, the walls and the ceiling, and it both quietens the cabin and stops the climate system fighting the outside temperature all day.

On climate, size for occupancy and running hours. First Class Customs fits 62,000 BTU of rear air conditioning with separate floor heat and a full insulation package to the VIP Shuttle, the highest occupancy line in the range. Separate floor heat is worth specifying on any build that will run in winter: ceiling vents do not solve cold feet, and cold feet end meetings early.

One honest limit. A van will never be as quiet as a room with no wheels on it. What a good acoustic specification buys you is a cabin where a call sounds normal at road speed, not silence.

Step 7: finish and materials

The finish is what you touch every day, and it is the part of the build that ages in front of you.

Three things to specify properly:

• Upholstery. Leather and the stitching pattern. First Class Customs builds its seating in house, so the options are not limited to a supplier catalogue.
• Woodwork and cabinetry. Grain, finish and edge detail. The curved wall work on the Ultimate Class line is cabinetry at the limit of what is practical in a van body, and it only works because the metal fabrication underneath was built to match.
• Lighting. Layered, not a single ceiling source. Task lighting at the desk, soft indirect lighting for the cabin, and the ability to run them separately.

Our deeper piece on luxury Sprinter van interior materials, tech and build covers the material choices in detail.

What a custom mobile office costs and how long it takes

A custom mobile office is priced on specification. In order of weight, the drivers are the seating, the layout and any privacy divider, the technology and electrical package, and the interior finish.

On timing, there are two separate waits and they should always be quoted separately: the Mercedes-Benz chassis, if one is not already allocated, and then the build itself from signed specification to delivery. A single combined number hides which half is slipping.

Builds are ordered factory-direct from the 30,000 square foot facility in Springfield, Missouri, so there is no dealer margin on top of the build.

Custom mobile office questions

What is a custom mobile office?

A custom mobile office is a van specified around the work being done inside it, so the layout, power budget, acoustics and connectivity are designed for that work rather than fitted from a catalogue. First Class Customs builds custom mobile offices on four Mercedes-Benz Sprinter chassis, plus the Metris, in house in Springfield, Missouri.

Can you work full time from a mobile office van?

Yes, if the electrical system, the acoustics and the seating are specified for it. The three things that stop people are a battery sized for an average day rather than a real one, an untreated cabin that makes calls unusable, and seats designed for short transfers. Specify all three properly and the vehicle holds up to daily use.

How much power does a mobile office van need?

It depends on what runs at the same time. A laptop draws 45 to 100 W, an external monitor 20 to 60 W, LED cabin lighting 20 to 60 W and a cellular router 10 to 25 W, while climate is several hundred watts and is the largest single load. The peak sizes the inverter and the daily energy sizes the battery. Those are two different numbers.

How long does a custom mobile office build take?

There are two separate waits: the Mercedes-Benz chassis, if one is not already allocated, and then the build from signed specification to delivery. Ask for both separately.

Can you stand up inside a custom mobile office?

On a Mercedes-Benz Sprinter with a raised or high roof, most adults can stand upright in the cabin. The roof choice decides this, not the floor length: a 144 chassis with a raised roof gives standing height in a short vehicle. The Metris is a seated cabin.

Is a custom mobile office cheaper than an office lease?

That depends on your lease, your mileage and your tax position, so it is a question for your accountant. What a manufacturer can tell you is what the vehicle costs and what it includes. First Class Customs provides the Manufacturer's Statement of Origin and the documented build specification, which is the paperwork an accountant will want.

Specify your custom mobile office

Bring the four answers from step 1 to the first conversation and the rest follows quickly. See the Private Class build with its three fold-out desks, or the compact Metris conversion, and talk to the build team in Springfield, Missouri.