JOLT vs Mobile Modular for jobsite offices

JOLT and Mobile Modular both put offices on construction sites, but they sell different buildings in different ways. JOLT rents ground-level steel container offices with the rent published, fixed delivery fees in five Rockies states and a written quote elsewhere. Mobile Modular rents, leases and sells modular buildings, from single-wide trailers to multi-unit complexes, and prices them by quote.

What does Mobile Modular offer?

Mobile Modular's modular office page lists four kinds of office: single-wide, double-wide, sales offices and office complexes. The same page invites you to rent, lease or purchase standard or custom offices, and it says double-wide units come new or used with customized layouts and financing options.

Its construction industry page (both checked October 29, 2026) describes jobsite trailers for purchase, extended leases or short-term rentals, shipped from locations nationwide. It also lists modular locker rooms and portable sales offices, and notes that product availability varies by region.

Mobile Modular is a division of McGrath RentCorp, according to its company history page. That matters for one reason: it is a national modular building company, not a container yard, so its range runs larger than anything a single shipping container can hold.

What does JOLT offer?

JOLT rents four office builds, each a steel container that sits on the ground:

• the 20 ft Base at $795/mo, with a mini-split for heat and cooling and a 50-amp shore-power inlet;
• the 20 ft Grid-Free at $1,495/mo, with solar, a 10 kWh battery that runs the HVAC, Starlink and a camera built in;
• the 20 ft Alpine at $1,895/mo, the Grid-Free with a matte black and cedar envelope, a standing-seam over-roof, a covered entry deck and backup heat;
• the 40 ft office with bathroom at $1,595/mo, on shore power.

We build many of these offices in our shop in Gypsum, Colorado, and modify and maintain offices there as well. Every 20 ft build is also for sale, or on a 24- or 36-month lease-to-own plan, and the mobile office rental page lists each price.

How do the prices compare?

They cannot be compared from the public pages alone, because Mobile Modular does not post a rent. Its construction page says the cost depends on the building's size, the lease length, whether the unit is new or used and the customization, and it routes every price to a quote request.

JOLT's rent is on the page, and so are the reservation deposit ($750 per office, credited to the first invoice) and the delivery fee in Colorado, Wyoming, Utah, Idaho and Montana. To compare fairly, ask Mobile Modular for a written quote that separates rent, delivery, setup, any skirting or steps, and return delivery, then add JOLT's delivery and pickup to its rent for the same number of months.

Which building fits the job?

Pick a JOLT container office when:

• the crew needs a private office or two, a plan table and a locked door;
• the site has no power, and the Grid-Free's solar, battery and Starlink beat running a generator;
• you want ground-level entry with no trailer stairs or ramp;
• you want to see the price before anyone calls you.

Pick a Mobile Modular building when:

• you need a large open office, a conference room or a complex of joined units;
• you need a locker room or a sales office the public will walk into;
• the building will stay for years and you want a modular structure built to match existing buildings.

Our container office versus modular building guide goes deeper into the trade-offs.

Delivery and setup

A container office arrives on a tilt-bed truck and is set on a firm, level pad. There are no axles, no tongue and no skirting, and the office is usable the day it lands once shore power is connected, or right away on a Grid-Free. JOLT's standard delivery window is two to four weeks after you reserve, and a Base office in Colorado can go express, on site within seven business days, for $795.

A modular building is a bigger delivery. Ask Mobile Modular's quote to name the setup work, such as blocking, leveling, steps or ramps and utility connections, with the cost of each and the delivery date.

Terms

JOLT's office minimum is three months in Colorado and 12 months elsewhere, then month to month. Written cancellation more than 14 days before the first day of the delivery window is free. For Mobile Modular, the minimum term, deposit and cancellation terms were not on the pages we read; confirm them in the written quote.

Power, heat and internet

Every JOLT office heats and cools with a mini-split. The Base and the 40 ft office run it on shore power through a 50-amp inlet, so the site needs a power drop or a generator. The Grid-Free and Alpine run it from their own solar array and 10 kWh battery, and Starlink internet and a camera come built in, which suits a remote site where waiting on a utility connection would hold up the job.

For a modular building, ask the quote how the unit is heated and cooled, what electrical service it needs, and who arranges the connection. Those answers decide how soon the crew can actually use the space.

What to ask for in each quote

A fair comparison starts with the same request sent to both companies. Write down the number of people who will work in the office, the length of the job, the delivery address, whether the site has power, and the date you need the office open. Then ask each supplier to answer the same list in writing:

• the unit offered, with its size, layout and what is inside it;
• the monthly rent and the minimum term;
• delivery, setup and return delivery, each as its own line;
• any steps, ramps, skirting, blocking or utility work, and who provides them;
• the deposit and when it is credited or refunded;
• the delivery date and what happens if it slips;
• how the rent changes if the job runs long.

JOLT's answers to most of these are published: the rent, the minimum term, the deposit, the delivery and pickup fee in the Rockies and the delivery window. For a JOLT office outside the Rockies the delivery and pickup come back in a written project quote within one business day. The Mobile Modular answers will come from its quote.

Buying and lease to own

Both companies sell. Mobile Modular offers purchase of new or used units with financing options. JOLT sells its 20 ft builds outright from $17,500 and offers a 24- or 36-month lease to own on each, with title on the final payment; see lease to own for the payments. For plain storage, JOLT also sells shipping containers on the containers for sale page.

The short version

If one or two offices will do, especially on a site without power, a JOLT container office is the faster path to a known price. If the job needs a building rather than an office, with many rooms or a permanent installation, ask Mobile Modular for a quote. The table at the top of this page sets the two side by side, with a link to every Mobile Modular page we read.