Reducing a Southern California HVAC Supplier's Freight Costs 11% Through Pallet Stack Height Optimization

For procurement and operations managers in manufacturing, the most impactful cost savings often come from the intersection of product design and logistics. A seemingly minor packaging change can ripple through the supply chain, affecting freight spend, warehouse efficiency, and even product integrity. This case study details how a Southern California HVAC component supplier partnered with Rox Packaging to achieve an 11% reduction in their outbound freight costs through a targeted redesign of a bulky item's corrugated packaging. The solution was not a complex new material, but a calculated optimization of pallet stack height.

1. The Challenge: Bulky Packaging and Sky-High Freight Bills

The client manufactures high-quality, pleated HVAC filters for commercial and residential systems. Their flagship product was a large, 20" x 25" x 2" filter, which was shipped to distributors and large contractors across California. Each filter was protected by a simple, full-overlap slotted container (FOL) made from 32 ECT, C-flute corrugated.

The Initial Packaging Profile

This configuration presented two critical problems.

First, the pallet height of 82 inches was problematic. While under the typical 96-inch trailer door height, it left minimal clearance for safe forklift handling and placed the load dangerously close to common warehouse racking limits. This often led to carriers charging dimensional weight penalties or requiring special handling, and it increased the risk of top-layer damage during transit.

Second, the inherent bulk of the filter meant each pallet cube was underutilized in terms of unit count. The 160-unit count was a hard ceiling dictated by the 8-layer stack. Every truckload shipped represented a significant volume of "air" being transported, directly inflating the cost per unit shipped.

2. The Engineering Analysis: Finding the Cubic Inch

Our engineering team's first step was to conduct a palletization efficiency audit. The goal was to identify every potential cubic inch that could be converted into a shippable unit. We focused on three key areas: box design, board specification, and pallet stacking physics.

Evaluating the Box Style

The Full-Overlap Slotted Container (FOL) is a workhorse for heavy items, offering excellent top-to-bottom compression strength. However, for a relatively lightweight but bulky item like an HVAC filter, this strength was over-engineering. The overlapping flaps added unnecessary board weight and, more critically, a slight but consistent increase in the assembled box's height at the seam. For a stack of 160 boxes, this millimeter-level variance accumulated.

Analyzing Compression Strength Requirements

Using the McKee formula and standard industry calculations, we determined the required Edge Crush Test (ECT) for the application. The filter itself weighed only 2.5 lbs. The primary stress was not top-to-bottom compression from extreme stacking, but rather side-to-side racking during transit. This allowed us to explore alternative, more space-efficient box styles without sacrificing protection.

KEY INSIGHT: The standard rule of thumb for palletized freight is to maximize trailer cube utilization. For non-fragile, low-weight items, the limiting factor is often stack height stability, not pure compression strength. Redesigning for a lower profile per unit can unlock additional layers per pallet.

3. The Solution: A Redesigned Sleeve and Optimized Stack

The breakthrough came from shifting from a fully enclosed box to a sleeve-and-tray design, coupled with a precise adjustment to the board caliper.

The New Packaging Specification

Why This Worked:

1. E-Flute Adoption: Switching from C-flute (~3.6mm) to E-flute (~1.6mm) significantly reduced the board's thickness. This directly subtracted from the per-unit height, allowing for tighter stacking. The 44 ECT rating of the E-flute board provided more than sufficient sidewall rigidity and top compression for the 9-layer stack.
2. Sleeve-and-Tray Design: The auto-bottom tray provided a stable base, while the separate sleeve slid over the product. This eliminated the height added by overlapping flaps and created a cleaner, more consistent vertical profile. The sleeve also offered excellent graphic presentation for retail-bound SKUs.
3. Tighter Tolerances: We refined the internal dimensions by an eighth of an inch on each side, achieving a snugger fit that prevented product movement and reduced the need for excessive board.

The result was a pallet that was actually 4 inches shorter (78" vs. 82") but contained 20 additional units (180 vs. 160), a 12.5% increase in density.

4. The Operational and Financial Impact

The new packaging design delivered benefits across three areas: transportation, warehousing, and sustainability.

Transportation Cost Reduction

By increasing the units per pallet from 160 to 180, the client immediately required one fewer pallet for every nine pallets shipped. This translated directly into an 11% reduction in the number of pallets needed per order. For a company shipping hundreds of pallets per month across California, this density gain lowered their freight costs proportionally, as they were now paying to ship more product in the same trailer space. The lower overall pallet height also eliminated previous accessorial charges for over-height freight.

Warehouse and Handling Efficiency

• Increased Storage Density: In their own warehouse and at distributor locations, the more compact pallets allowed for better use of vertical racking space.
• Reduced Touch Points: Fewer total pallets to handle meant less forklift movement, fewer scan points, and lower labor overhead per unit shipped.
• Improved Stability: The lower center of gravity and uniform sleeve design created a more stable pallet load, reducing the risk of tip-overs in transit or storage.

SUSTAINABILITY: This project aligns with core sustainable packaging principles: source reduction. By using a thinner, stronger board (E-flute) and eliminating material through design efficiency, we reduced the total fiber consumed per unit. Furthermore, shipping 12.5% more product in the same space lowers the overall carbon footprint per filter delivered. Learn more about our approach to sustainable packaging.

5. Implementation for Your Operation

Pallet stack height optimization is a universal lever for cost control. Here is a simplified decision matrix to assess if your packaging is a candidate for a similar review.

The process begins with data. Before engaging a packaging partner, gather: current box specs, pallet patterns, unit weight, and any freight invoices noting dimensional weight or over-size charges.

6. Partnering for Packaging Efficiency

At Rox Packaging, we approach packaging as a system integrated with your logistics. Our 25 years of expertise serving California manufacturers in CPG, food, beverage, and 3PL is focused on engineering solutions that impact the bottom line. We operate on a pallet-scale, with MOQs starting at 1,000 units, making us a strategic fit for small-to-mid-sized manufacturers looking for wholesale efficiency without wholesale complexity.

For readers with lower volume needs, we mention our sister brand, Build A Box Online, which handles short-run, no-MOQ orders. For the pallet-scale projects that drive significant freight and operational spend, the path forward is a detailed, data-driven RFQ.

The most effective way to start a conversation about optimizing your packaging for freight savings is to submit your specifications through our RFQ form. This allows our engineering team to provide a meaningful analysis and quote based on your specific product dimensions, volumes, and supply chain requirements. You can also reach us at (888) 406-1610. We are located at 4080 N Palm St, Ste 803, Fullerton, CA 92835, manufacturing and shipping corrugated solutions across California.