03/19/2023 3:23PM

5 Types of Refrigerated Semi-Trailers

When choosing the best type of reefer trailer, you must consider several factors.

Factors include the kind of products you will be hauling, where you are hauling if you will have backhaul loads, how to maximize your hauling opportunities, and more.

Let’s look at some of the most important factors to consider when choosing a new reefer trailer or used reefer trailer spec’d to meet the specific needs of your business.

1. The Standard Reefer Trailer

80% of product types are hauled in a standard reefer trailer. 

Standerd Reefer Trailer Specs:

  • Payload Capacity: 55,000 lbs. Evenly Distributed
  • The temperature range is 0-55 degrees
  • Tare Weight w/ Tires and Wheels: 12,455, plus an additional 2000LBS for the reefer unit.
  • Floor: 1 1/2” Deep Heavy-Duty Aluminum Duct Floor
  • Insulation: 4” on the front wall, 3’ in rear doors, 2” inside walls
  • Standard reefer units: CA X4 7300 or TK Precedent C-600 (Standard for 80% of hauls)
  • 53’ Trailer: 53×102, 13.6” H
  • Lights: LED Standard is (2-0-1-5): Two on the Front, 0 on Top Rail, One on the Bottom Rail, and Five on Rear
  • Wheels: 22.5 Steel Disc Wheels & 22.5 Low Profile Tires
  • Wearband: 10” High, Heavy-Duty Extruded Aluminum Wearband/ Floor End Plank
  • Side Panels: Flat, Smooth, pre-painted white

80,000 lbs. GVWR is the federal maximum allowable weight you can haul in a standard 53’ trailer. That includes the total combined weight of the truck and driver and all personal materials, the trailer and product inside the trailer, and all fuels for the truck and the reefer unit.

2. Reefer Trailer for Hauling Produce

If you know you will be hauling produce in your reefer trailer, you want to consider airflow and floor options to keep your product fresh. Some things to consider are the types of trailer refrigeration units, airflow, vents, and the advantages of the flat or duct floor.

Trailer Refrigeration Units

The standard refrigeration temperature for hauling produce is about 36 degrees. We recommend the C600 from Thermo King and the X4 7300 from Carrier. Check out our inventory of Thermo King and Carrier units.

Two Options for Continuous Airflow in your Reefer Produce Trailer include: 

  1. Fresh Air Option: There’s a fresh air option with the reefer unit that will allow airflow to go through the unit and hit the back doors, where it will exit through the rear vent door. 
  2. Front Vent Door: Consider a Front Vent Door (if you don’t have the fresh air option) to allow for airflow.

Two product types that require airflow are watermelon and potatoes. You don’t need the reefer unit as much, and the airflow will take care of that product.

Reefer Trailer Floor Options

To know what type of floor you need in your trailer for hauling produce, you must first know what product you are hauling.

Duct Floor option: 
This 1 1/2-inch-deep aluminum duct floor, which comes standard on reefer trailers, will allow airflow to travel through the ducts and allow boxed floor loading or palletized loading. 90% of owners use a duct floor.

Example: Meat or yogurt is a boxed product that goes right on the floor on a slip sheet. The duct floor allows air to flow through the grooves in the floor under the product without needing the product to be elevated on a pallet.


  • Improved airflow.
  • It does not require palletized products.
  • Lighter weight than the flat floor.


  • Cleaning is more difficult than with a flat floor.
  • Some pallet jacks have small wheels that could get caught in the duct floor.

Flat Floor option:
Flat floors typically require you to palletize your product so the air can flow through the pallet. 

The flat floor is easier to clean out. It is stronger, and it allows your product carts to move around easier without getting stuck in the duck floors. But it is heavier and will cost more than a duct floor.


  • Easier Clean Out.
  • Stronger: Added aluminum in the stress areas. The floor planks are heavier and stronger.
  • Smooth Cart Operation. Allows your product carts to move around more easily without getting stuck in the duct floors.


  • Heavier: Adds approx. 539 lbs. to the weight of the trailer.
  • Costs More: Approx. $1000 more than duct floors.
  • Typically requires you to palletize your product so the air can flow through the pallet

3. Deep Frozen Reefer Trailer Specs

If you know you’ll haul product at 0 to -20 degrees, you want to be sure you’re specing your reefer trailer for deep-frozen.

Some things you want to consider are your clearance needs, insulation options when considering backhauling other product types, and spec’ing the correct reefer unit. Proper insulation and the right reefer unit are critical to keeping a 0 -20 consistent temperature.

Interior Dimensions and Insulation Packages for Reefer Trailers.

standard reefer trailer insulation is 2” in the side walls and 3” in the floor and ceiling.

For deep-frozen applications, you will add 1” of insulation to the ceiling and floor for a total of 4”, increasing your insulation factor for -20 and below. However, consider your backhaul opportunities before adding another 1″ of insulation to your sidewalls.

Why? A standard reefer trailer with 2″ of sidewall insulation = 97 ¼ interior width (wearband to wearband). This dimension will fit (2) pallets with space left over.

But, for every 1” of insulation you add, you will lose 2” of inside width and height. Adding another 1” to the sidewalls for the deep-frozen application will decrease your loading by 2 inches, limiting your backhaul opportunities. If you’re planning on hauling other product types on your backhauls, you won’t be able to get a standard pallet in that trailer insulated for deep-frozen products. 

How to spec a new reefer trailer to haul both deep frozen and produce and other general commodity products.


Insulation requirements:

  • 2″ insulation in the side walls to accommodate standard pallets.
  • 4″ insulation in the floor and ceiling.
  • Add a 4″ Wedge to keep the 105″ floor to ceiling height.

By increasing insulation and using the wedge design, you gain versatility with various backhaul opportunities and increased earnings potential.

4. The High Cube Trailer

A High Cube Capacity Reefer Trailer is built on a Wedge Design where the rear height is greater than the front, allowing for a higher stacked product. The inside front height is increased by 3″, and the rear is increased by 6″.


If you build the reefer with the Thin Insulation in walls, ceiling, and floor and build it on a Wedge Design, you can get up to 98″ inside width110″ rear door opening height, and up to 107″ inside at the front. 

This design allows you to load dry freight like potato chips or snack foods one way and refrigerated products on your return trip.

And you won’t be building a white elephant. Instead, the versatility of this reefer trailer can increase your ability to resell it in 5, 7, or 10 years.

Thin Insulation + High Cube Design + High BTU Unit.

Design your reefer trailer for hauling deep-frozen and still have the interior space needed to carry pallets of produce or general commodity.

Specs include:

  • Low-Profile Rear Door Header. Modifies the rear door frame for high-capacity specifications to get a 110″ inside the opening.
  • Shallow Front Subframe. Change the front subframe to get 107″ inside.
  • High BTU Unit. Going to thinner insulation will require a greater cooling capacity reefer unit – higher BTUs. You’re reducing your thermal efficiency with thin insulation; the higher BTU unit allows you to haul the deep-frozen.
  • Cross Member Configuration: Downsize from 4″ to 3″ high cross members. Keeps height 13.6″. Space cross members at 8″ instead of 12″ to get the same rating.

5. Reefer Trailer for Heavy Haul

Scenarios of heavy haul applications are bulk loads, anything that loads against the side walls like watermelon or potatoes, or even a backhaul load such as carpet. In these situations, you want to consider heavy haul options and evaluate your need for a tow-motor package.

Heavy Haul Options

Consider adding these heavy haul options sooner rather than later. It will cut down on maintenance costs and increase the life of the trailer.

  • Space Side Posts closer together (12″, 16″, 24″)
  • Space Roof Bows closer together (24″ or 48″)
  • Add a Heavy-Duty Top and Bottom Rail
  • Add a Heavy-Duty Floor
  • Cross Member Spacing:12” is standard. Go to 10″ or 8” for added strength

What type of tow motor will enter your trailer?

Standard duct floors are rated at 20,000 lbs. So, if you’re entering a standard duct floor with a 24,000 lb. tow motor and product, you’re within the maximum allowable capacity of 20,000 lbs., with 80% of the total weight (19,000 lbs.) on the front axle.

Are you hauling heavy? Do you need to consider a tow motor package?

  • How much does your tow motor weigh?
  • How much does your product weigh?
  • Does the tow motor have 7” wheels, or does it have the standard 12” wheels to distribute the weight? If the tow motor has 7” wheels, that can mean serious trouble. The weight will be concentrated and can break the trailer a lot faster. And that’s not covered by a warranty.

A tow-motor package can help prevent damage to the floor of your trailer. 


  • Adds additional I-Core Inserts at the rear of the trailer floor. The most common is 36” deep and can go to 72”.
  • Adds additional diamond plate at the back, welded to the top of the floor at the rear. Adds additional protection from wear and tear.
  • Add additional dock plates for damage protection.
  • Additional sidewall wearband available in 6” increments
  • Buck plate thickness can be upgraded from 3/8” standard to 5/8” HD.
  • Heavier duty door frame. The standard is 12 ga. You can go to 8 ga.

Multi-Temp Reefer Trailers

If you are considering running a multi-temp trailer, read our series blog series on Multi-Temp Trailers to read about:

  1. Temperature Ranges and Zones in Multi-Temp Trailers
  2. Product Safety Features for Multi-Temps
  3. Multi-Temp Trailer Backhaul Restrictions 
  4. Bulkheads and Dividers for Multi-Temp Trailers
  5. Exterior and Interior Lighting Options for Multi-Temp Trailers
  6. Dimensions of a Multi-Temp Trailer
  7. Driver Safety for Multi-Temp Operations
  8. Heat Evaporator Placement and Airflow in Multi-Temp Applications
  9. Remote Control and Shor Power

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