When Labor Counts, HVAC Suspension Methods Matter

When HVAC contractors compare suspension systems, the price of materials is often the most visible cost — but it may not tell the whole story.

It might not get the attention that other aspects of the HVAC industry receive, but HVAC suspension is vitally important. How ductwork, piping, and equipment are supported affects labor costs, installation speed, and safety, in addition to the long-term system performance. HVAC contractors must ask themselves, what is the actual cost of suspension?

A suitable place to start is with the material price. That is a number most contractors focus on first, which is fine as long as it is not the only item they think about. The starting point should be: the cost of cable, rod, hardware, etc.; quantity required; and shipping/material handling cost.

Step two for contractors is to calculate the installation cost.

“At the end of the day, your labor costs are going to outweigh the price of the material. If someone is looking only at the difference between the price of threaded rod and strut versus cable, they’re missing part of the equation. You have to take that material difference and factor in the labor required to install each system,” Brian Pimental, HVAC Sales Manager for Griplock Systems, said.

The key metric becomes labor dollars per installed suspension point, not just the price of the materials. Cutting and deburring rod, handling nuts and other hardware, and completing the additional installation steps all add labor to the job. There are also smaller job-site expenses that can easily be overlooked, such as replacing extension cords damaged by scissor lifts and other equipment. Because cable suspension requires fewer saws, grinders, and other power tools, contractors may need fewer extension cords on the job site, reducing another hidden cost that isn’t always considered when comparing material prices.

Cable suspension systems help simplify the installation process for contractors.
 “It eliminates the need for tools for cutting and deburring. The cable comes ready to hang in a box, so you are not dealing with pallets or flatbed truckloads of strut,” Larry Dalton, HVAC Sales Manager for Griplock Systems, said. “If you have 10-foot sticks of strut and you need 6-foot lengths, you’ve got to cut every one of them and clean them up before they are ready to use. The same thing applies to rod. Cable is a much simpler and easier way of suspending ductwork.”

Traditional threaded-rod installation can add time to a project because of the number of touch points required on the job site. Installers may need to make multiple trips up and down on a scissor lift to cut the rod and strut, deburr the material, install the nuts, and set the proper elevations. With cable suspension, installers can keep a box of cables on the lift, reducing trips and installation steps while also making it easier to work around other trades on a crowded job site.

Here are the key factors in the equipment and tools that contractors should be aware of:

Cutting equipment — Cutoff saws, band saws, or other tools needed to cut rod to length. 

Grinding/deburring — Cut ends may need to be cleaned up to remove sharp edges or burrs. 

Grinders/cutoff wheels — Consumables have a cost and wear out over the course of a project. 

Nuts and washers — Often numerous small components that add both material and handling costs. 

Strut and fittings — Depending on the suspension design, threaded rod may be paired with strut, clamps, angles, or other hardware. 

Lifts and access equipment — The equipment itself isn’t unique to threaded rod, but the amount of time a crew needs it can be. 

Extension cords and jobsite power — Cutting and grinding equipment can require access to power. 

PPE and safety considerations — Cutting and grinding introduce sparks, sharp edges, and metal debris that may require additional precautions. 

Material staging — Long lengths of threaded rod can require more space for transportation, storage, and staging on the jobsite. 

Material handling — Moving bundles of long, relatively heavy rod through a building can add time that isn’t reflected in the purchase price. 

The final item contractors must consider is the next job. If a crew can complete an installation in less time, they are not just saving money on the current job, they’re potentially freeing up manpower to start the next job sooner.

“By utilizing a cable hanging system, you’re going to be cutting the installation time substantially, which means you’re going to get off the job faster and move your guys to another project. When you are bidding a job, that’s a huge consideration. If you can cut your labor by 50%, that is a significant dollar amount,” Pimental said.

This is especially important with the workforce problem happening in the HVAC industry.

“Contractors bid these jobs with a certain time frame in mind. If you can finish sooner, you have more time available for the next job,” Dalton said.

The bigger the job, the more important installation efficiency becomes. Think about how many trucks have to come onto a large job site carrying threaded rod and strut compared to one pallet of cable. When you’re talking about a massive project, the difference in material handling alone can become significant.

The key takeaway for contractors is when comparing suspension systems, they need to make decisions based on total install cost rather than material price alone.

“They have to try it. Take a single run of ductwork, put two guys on one side with rod and two on the other with cable suspension, and time it. If they’re willing to do that, they’ll see how much sooner they can finish with cable suspension. We’ve seen it over and over. The best way to understand the ease of use, the time savings and the labor savings is to actually put the product in their hands and let them prove it to themselves,” Dalton said.