Upfitting an enclosed truck
Enclosed service bodies are the go-to truck type in many industries, from utility companies and over-the-road service to HVAC, plumbing and electrical work. Available in a wide variety of sizes and styles, enclosed trucks often feature side-access storage and a secure cargo area for tools and equipment.
Because load space is typically at a premium, choosing the right equipment in the upfitting process is important for efficiency and productivity.
All-in-one power systems can be used in some enclosed trucks and offer numerous benefits in these applications. However, proper installation is critical to ensure the proper cooling air is provided and hot air is routed outside the truck. An all-in-one that is improperly installed can restrict airflow, provide poor performance and cause the unit to overheat.
Learn more about the advantages of all-in-one solutions and get four tips for proper installation in enclosed body trucks.
Benefits of an all-in-one
Integrated all-in-one solutions deliver benefits that can improve operator efficiency and comfort. These include:
- Space savings: When one unit provides all the necessary capabilities to tackle a range of jobs in the field, it eliminates the need to carry multiple pieces of equipment. A Miller® EnPak® all-in-one provides compressed air, generator power, battery charge/crank assist and welding in a small footprint.
- Noise reduction: Auto Start/Stop automatically turns the EnPak engine on and off based on demand, reducing fuel consumption and noise — which enhances safety and improves the work environment. In addition, Auto-Speed™ technology automatically adjusts engine speed to match compressed air, battery charge and weld demands — reducing noise for a safer, more efficient work environment.
- Access and convenience: Remote auxiliary panels available with EnPak solutions provide versatility in where the machine is located versus where the controls are for the user. This helps optimize the available space in a truck. For example, the technician can add outlets where their worktable is located. Properly located remote panels also enhance safety, since the technician doesn’t have to move around as much or move their equipment to use it.
It’s important to think through the design and layout of an enclosed truck in order to optimize all-in-one performance and safety. Every install is different but keeping best practices in mind when installing an all-in-one solution on an enclosed truck will help greatly.
Here are four tips for installation in an enclosed truck:
Tip 1: Don’t bury the unit

Using an all-in-one inside an enclosed truck requires proper ventilation around the unit to ensure airflow of cold air in and hot air out. If the all-in-one system doesn’t have enough airflow, the machine can overheat. This negatively impacts performance and machine life. An under-deck installation is an option worth considering on some chassis.
Tip 2: Duct directly to the outside

Think of the enclosed truck body as a closed system. Engines and other components produce heat, so adequate air circulation is required for cooling. Fresh, cool air must be brought in, and hot air must be removed. The best way to prevent recirculation of the hot air created by an all-in-one is to either duct the hot air directly to the outside or duct cool air into the air intakes.
In addition, engine exhaust fumes must be ducted to the outside because they contain carbon monoxide. Never use an EnPak all-in-one inside a home or garage, even if doors and windows are open. Always read and follow all labels and the Owner’s Manual carefully.
Avoid using exhaust pipe extensions or extra elbows to duct the exhaust fumes. This will cause back pressure in the engine exhaust and reduce flow through the combustion chamber. This compromises engine performance and can cause exhaust emissions issues.
Ideally there would be no exhaust pipe extensions, but when extensions must be used, keep them to a minimum. Any extensions require the use of larger-diameter tubing — at least one and a half times the diameter of the stock exhaust pipe.
Routing exhaust through the floor of the truck is discouraged because it requires at least two additional bends and several feet of exhaust pipe — resulting in excessive exhaust back pressure. Instead, it’s recommended to route exhaust through the closest sidewall or straight up through the roof if the unit is mounted on a stand.