December 2022

Master-Bilt® Refrigeration News & Product Information

Choosing The Best Walk In Panel

Walk-in cooler with two doors.

Edited 4-17-23

Choosing the best walk-in panel generally comes down to a couple of factors: what’s inside the panel and how it’s constructed.

When it comes to walk-in coolers and freezers, probably no factor makes a bigger difference in performance than the panel insulation. There are different types of insulation and they can vary widely in efficiency.

Next to insulation, the panel construction type plays a huge role in walk-in efficiency. How the panels are made and how they fit together determine how well they prevent heat leaks and hold the cold air inside.

What’s inside the panels and how they are constructed determines overall cost of ownership, so it makes sense to go with a manufacturer using the most efficient insulation and construction methods.

This article looks at two of the main insulation types as well as several panel construction methods. While there are advantages and disadvantages of each insulation and construction type, one combination emerges as the clear frontrunner.

Walk-In Panel Insulation Types

Master-Bilt walk-in panels contain polyurethane insulation for highest efficiency.

Polyurethane foamed walk-in panels supply the highest energy efficiency.

The insulation found inside walk-in panels can be made up of several different types of materials. Two of the most common are polystyrene and polyurethane. Polystyrene can be further broken into two types: Expanded polystyrene (EPS) or extruded polystyrene (XPS).

EPS is created by expanding small beads of polystyrene inside a mold. Applied heat and pressure cause the beads to merge to form the panel shape. Individual beads are closed cells but there are sizeable open spaces between the beads. For reference, a common example of EPS is Styrofoam.

XPS is made by injecting liquid polystyrene plastic into an extrusion mold which creates a foam panel. XPS insulation is also a closed-cell type but is denser than EPS. XPS is also typically considered to have a better insulation quality than EPS.

Polyurethane foam is a mixture of two chemicals known as isocyanurates and polyols. These two chemicals are usually injected into a flat fixture or mold. When they meet, the resulting reaction causes a rapid, steady expansion which fills the fixture and forms the panel.

Polyurethane Insulation Pros & Cons

Any discussion of polyurethane or polystyrene must begin with R-value. Stated simply, R-value is the capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating ability.

Polyurethane’s greater heat resistant properties mean a refrigeration system doesn’t have to work as hard to keep inside air cold, which saves energy and, in turn, operating costs. In fact, polyurethane panels typically have an R-value of 32 which meets or surpasses DOE regulations.

Walk-In cooler polyurethane insulation has a higher R-value than polystyrene

Polyurethane insulation provides a higher R-value than polystyrene.

Other advantages include:

  • Polyurethane foam permanently adheres to metal panels adding strength and reliability
  • Superior moisture resistance due to polyurethane’s 97% closed cell content
  • Maximum walk-in storage space because polyurethane foam allows for thinner walls in comparison to other foam choices
  • Polyurethane is a thermoset material which means it won’t melt. Because of its ability to resist fire, polyurethane earns a UL Class 1 rating.

One of the most common disadvantages cited against polyurethane is that it loses R-value over time. Actually, both polystyrene and polyurethane can experience some fall-off over the years. What’s frequently not taken into consideration is that, with polyurethane, this drop is usually due to the panel being exposed to the elements. However, in real world situations, polyurethane foamed panels are mostly encapsulated and not exposed to the elements.

Polystyrene Insulation Pros & Cons

Polystyrene panels may cost less than polyurethane and they are lighter and easier to handle. In addition, they provide good resistance to water and airflow.

However, polystyrene’s lower R-value results in increased operating cost. Wall thickness must increase for polystyrene to match polyurethane’s R-value which reduces available walk-in storage space.

Other polystyrene disadvantages include:

  • Poor ultraviolet radiation resistance
  • Poor resistance to chemicals including organic solvents
  • Polystyrene panels can only use hard nose construction types (more on that later)

Panel Construction Types

Most soft nose walk-in panels have tongue and groove construction to provide a tighter fit.

Most soft nose walk-in panels have tongue and groove construction to provide a tighter fit.

Walk-in panels generally fit into one of two main construction types: soft nose or hard nose, also referred to as hard rail.

Soft nose construction means there is no hard rail or wood along the panel edge. Their edges are made of the same polyurethane foam as the rest of the panel. With these softer, more flexible edges, soft nose panels fit together better than other types.

Hard nose panels have edges made from wood or high density foam rails. These edges are less insulating and don’t seal as thoroughly as soft nose.

Walk-in panel with hard nose design

Hard nose walk-in panel with high density foam rail edge.

Panels also connect to each other using different methods. Some panels are flat and require silicone sealant to form a bond. On the other hand, many soft and hard nose panels have a tongue and groove design to help them fit together better. The protruding tongue of one panel fits into the groove of the adjacent panel with each panel locked together by cam-locks or bolts.

Of all the assembly methods, cam-locks are best because they not only form a dependable seal but also make it easy to assemble and disassemble a walk-in. Should the walk-in need relocation or expansion, panels can be taken apart as easily as they are assembled.

Cam-lock assembly is best because it makes it easy to assemble and disassemble a walk-in as needed.

Cam-lock assembly makes it easy to assemble and disassemble a walk-in as needed.

Standard panel thickness varies but many are around four inches. But keep in mind that even though the thickness may be the same, the insulation type makes a big difference in performance. Some manufacturers offer additional thicknesses of five or even six inches to provide additional insulation efficiency as well as an added support in snow load situations.

Here are some of the most common panel construction and assembly types along with advantages and disadvantages of each:

Soft Nose – Cam-Lock

  • Insulation type: Polyurethane
  • Assembly type: Tongue and groove with cam-lock
  • Creates a more thermally efficient and tighter seal than hard rails
  • High and consistent R-values
  • Cost effective

Wood Frame – Lock/Receiver

  • Insulation type: Polyurethane
  • Assembly type: Lock and receiver with tongue and groove
  • Added structural strength from the wood
  • Decrease in R-value due to hard nose connections
  • Wood decays if not sealed properly

Wood Frame – No Lock/Receiver

  • Insulation type: Polyurethane
  • Assembly type: Flat connection surface with silicone seal
  • Added structural strength from the wood
  • Wood decays if not sealed properly
  • Less thermally efficient seal compared to the wood frame with lock/receiver

Hard Nose – Composite Extruded Connection

  • Insulation type: Polyurethane
  • Assembly type: Tongue and groove with silicone seal
  • Added structural strength from plastic extrusion

Polystyrene – Stick And Glue

  • Insulation type: Polystyrene
  • Assembly type: Wood frame and hard nose construction types, tongue and groove, sheet of polystyrene insulation glued to metal finish
  • Lowest R-value
  • Polystyrene can only be used for hard nose connections
  • Generally lowest panel cost
  • Less thermally efficient, increases heat leakage and operating costs
  • Added labor cost compared to soft nose polyurethane – cam-lock panels


After reviewing insulation types along with construction methods, it’s clear that soft nose polyurethane walk-in panels hold an advantage over other types.

The insulation is more energy efficient and the seal between panels is more airtight. When you add tongue and groove construction and cam-locking assembly, the choice becomes even clearer.

Remember, while you can spend less upfront for a walk-in with cheaper insulation or construction, you pay for it in the end with higher energy bills and possible loss of stored product. So, when planning your next walk-in, make sure you are using the most efficient solution for your business.